Doppler Weather Radar - METNET - India Meteorological Department

Ministry of Earth Sciences
INDIA METEOROLOGICAL DEPARTMENT
Doppler Weather Radar
Palam, New Delhi

STANDARD OPERATING PROCEDURE
FOR
DOPPLER WEATHER RADAR-98D/S
INDIA METEOROLOGICAL DEPARTMENT (IMD)
DOPPLER WEATHER RADAR, PALAM NEW DELHI-61
GOVT. OF INDIA
MINISTRY OF EARTH SCIENCES,
INDIA METEOROLOGICAL DEPARTMENT,
WEATHER RADAR DIVISION
04 AUGUST 2011
Compiled by
Shri Manik Chandra
Shri Rakesh Kumar
Shri B. A. M. Kannan
Dr. Y. K. Reddy
Shri P. S. Sastry
O/o DDGM (UI), Lodi Road, New Delhi – 110 003, India
Telefax: 24611451
Website: http://ddgmui.imd.gov.in
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Preface
Introduction
Definitions
Purpose
Objectives
Scope
Table of Contents
Pages
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ii
iii
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iv
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CHAPTER 1 MONITORING OF DWR SYSTEM 1-25
1.0 Safety of personnel and equipment and first aid and emergency rescue 1
1.0.1 Safety Precautions for all the A/C Plants 1
1.0.2 Safety Precautions for UPS 1
1.0.3 Safety Precautions for Generator 2
1.1 Radar and its equipment switch on procedure 2
1.2 Radar and its equipment switch off procedures 4
1.3 Bringing Radar to “STANDBY” & REVERTING (for few minutes 6
1.4 Monitoring DWR system and checking radar status 6
1.5 Precautions for VPN connectivity 8
1.6 Connection among modem, router and switch box 8
1.6.1 Lighting Status of Modem, Router and Switch Box in Working 8
Condition
1.6.2 Connections of vpn circuit 9
1.6.3 Checking VPN connectivity 10
1.6.3.1 If products not getting updated on IMD website only 10
1.6.3.2 If the products are not getting updated on FTP-server and IMD website 10
1.6.4 Logical flow diagram for checking VPN connectivity 12
1.7 To get back the products received at ftp server 13
1.8 Copying of raw product from a server 14
1.9 Configuring and scheduling of a scan strategy 14
1.9.1 Checking whether new scan strategy is working 17
1.10 Procedure for generation of dwr products 18
1.10.1 Adding, removing scheduled products 22
1.10.2 Editing the product configuration of the schedule products 22
1.10.3 Scheduling and stopping product generation 23
1.11 How to see other radar site archival raw data at your local computer 23
1.12 Uploading products on India Meteorological Department’s Website 23
1.13 Sequence of actions in case of radar breakdown 24
1.14 Standardizing a product 25
Table 1.1 Connection of Switch Box 9
Figure 1.1 Radar operating panels 2
Figure 1.2 Picture of Tx panel showing indicators when radar is in function 4
Figure 1.3 Emergency stop 5
Figure 1.4 Creating real time display on desktop of server 7
Figure 1.5 Modem, router front side and switch box back side view 8
Figure 1.6 Modem, router back side and switch box front side view 9
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Figure 1.7 Logical steps for checking vpn connectivity 12
Figure 1.8 Connecting to MAIN Server 15
Figure 1.9 Clicking pull-down Menus 15
Figure 1.10 Window after connecting with RCP8 15
Figure 1.11 Window of Task configuration 16
Figure 1.12 Scheduling task 16
Figure 1.13 Opening iris and configuring a new product 19
Figure 1.14 Saving new product with a name 19
Figure 1.15 Scheduling the configured product 20
Figure 1.16 Skipping the processing 21
Figure 1.17 Processing all selected tasks 21
Figure 1.18 Generated new product 22
CHAPTER 2 DOPPLER WEATHER RADAR DOCUMENTATION 26-31
2.1 Routine documentation work 26
2.2 List of Documents 27
2.2.1 RADAR STATUS Register 27
2.2.2 Fault log book 27
2.2.3 Complaint Book 28
2.2.4 T-log book 28
2.2.5 A-log book 28
2.2.6 Spare parts inventory 29
2.2.7 Event log book 29
2.2.8 Notam-information to NTC 30
2.2.9 VPN Connectivity Status 30
2.2.10 E-Mail Register 30
2.2.11 Other important works related with DWR operation 31
Table 2.1 Names of tables 26
Table.2.2 Radar status register 27
Table 2.3 Fault log book 28
Table 2.4 Complaint book 28
Table 2.5 Spare parts register 29
Table 2.6 Event log book 29
Table 2.7 Notam register 30
Table 2.8 VPN Connectivity Status 30
Table 2.9 E-mail register 31
CHAPTER 3 ADDITIONAL OPERATIONAL INFORMATION 32-42
3.1 How to send latest products direct to IMD website manually, when 32
VPN fails
3.2 Checking radiation of radar 33
3.3 Checking the current directory 34
3.4 To copy into pen drive 34
3.5 To check whether the given file was copied into pen drive 35
3.6 To delete all files from the directory 35
3.7 To search for a file 35
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3.8 To copy RAW DATA 35
3.9 Procedure for archiving raw data 35
3.10 Procedure for finding the size of a folder 35
3.11 To check availability of raw data 36
3.12 How to find the sweep angles of a given product 36
3.13 Script for sending the .gif images to ftp server 37
3.14 To send a configured product from main to destination 38
3.15 To mount a pen drive 38
3.16 Script for transgif (to send the configured products to destination in ftp 39
server)
3.17 How to copy the products from iris server into pen drive 40
3.18 How to copy the error log files from rcp8 40
3.19 Responsibilities of Station In-Charge 41
3.20 Responsibilities of operator 41
Figure 3.1 Checking radiation of radar 34
CHAPTER 4 DWR MAINTENANCE APPROACH 43-53
4.1 General Information 43
4.2 Maintenance 43
4.2.1 Preventive Maintenance 43
4.2.2 Corrective Maintenance 45
4.2.2.1 Electro-mechanical Assemblies 46
4.2.2.2 Printed Circuit Cards 46
4.2.2.3 Peripheral Communication Devices 46
4.3 Bitex utility 46
4.3.1 Bitex configuration 47
4.3.2 Bitex units and their parameters 47
4.3.3 Bitex data point configuration 52
Screenshot 1 Opening BITEX window 47
Screenshot 2 Cal Control &Results, Op. Control & RF Gen. Status 48
Screenshot 3 DCU AZ & EL Status 49
Screenshot 4 DCU General & Self test Status 49
Screenshot 5 DAU Bytes 0-3 and 4-7 50
Screenshot 6 DAU Bytes 8-11 and 12-13 50
Screenshot 7 DAU Analog Status 51
Screenshot 8 Histogram of Tx RF Avg. Power 51
Figure 4.1 Bitex main panel when fault came 53
APPENDIX A AN OVERVIEW OF DOPPLER WEATHER RADARS 54-59
A.1 Doppler weather radar system overview 54
A.1.1 Future IMD Radar Network plan under Modernization 55
A.2 Brief introduction of WSR-98D/S Doppler Weather Radar 56
A.2.1 Radar Data Acquisition (RDA) Group 56
A.2.2 RVP8 Group 56
A.2.3 RCP8 Group 57
A.2.4 IRIS Group 57
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A.3 Base products received from Doppler weather radars 57
A.3.1 Reflectivity factor (Z) 57
A.3.2 Doppler velocity (V) 58
A.3.3 Spectral Width(W) 59
Figure A.1 Cyclone Detection Radar Network 54
Figure A.2 Strom Detection And Multimet 54
Figure A.3 General Signal Flow Chart of Radar System 55
Figure A.4 Basic Block Diagram of Radar 55
Figure A.5 Reflectivity factor 58
Figure A.6 Doppler velocity 58
Figure A.7 Spectral width 58
APPENDIX B WSR 98D/S DWR SYSTEM CHARACTERISTICS AND 60-72
CAPABILITIES
B.1 WSR 98D/S System characteristics 60
B.1.1 General 60
B.1.2 Transmitter 60
B.1.3 Receiver 60
B.1.4 Antenna system 61
B.1.5 Antenna Scan Details 61
B.1.6 Radome 62
B.1.7 Displays 63
B.1.8 RVP8, the best and latest Radar Signal Processor 63
B.1.9 Calibrations And Health Monitoring 64
B.1.10 Built In Test Equipment (BITE) Processor 64
B.2 Capabilities of Doppler weather radars 65
B.2.1 Modes of Operation 65
B.2.2 Parameters to be measured 65
B.2.3 Observation Range 65
B.2.4 Spatial Resolutions 65
B.2.5 Measurement Accuracy 65
B.2.6 Unambiguous Range 66
B.2.6.1 Ambiguity resolution 66
B.2.7 Product Generation 66
B.2.7.1 Product range 66
B.2.8 Operating Environmental Conditions 66
B.2.9 Modes Of Operation 67
B.3 Product generation control and display capabilities 68
B.3.1 Base Products 68
B.3.2 Primary Products 68
B.3.2.1 Maximum Display 68
B.3.2.2 CAPPI (Constant Altitude Plan Position Indicator) 68
B.3.2.3 PCAPPI (PSEUDO CAPPI) 68
B.3.2.4 VCUT (Vertical Cut) 68
B.3.2.5 EBASE (ECHO BASE) 68
B.3.2.6 ETOP (ECHO TOP) 69
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B.3.3 Velocity Products 69
B.3.4 Hydrological Products 69
B.3.5 Aviation Products 69
B.3.6 Warning And Forecasting Products For Tropical Regions 70
B.3.7 Alphanumeric Products 70
B.4 Workstations and Display capabilities of the system 70
B.4.1 Workstations 70
B.4.2 Display capabilities of the system 71
B.5 Radar data archival capability 71
B.6 Operational limitation 72
APPENDIX C CALLIBRATION PROCEDURES 73-80
C.1 Callibration procedures of panel meters 73
C.2 Callibration procedure for dynamic range 76
C.3 Arc detector test 79
Figure C.1 Tx Control Panel A1, Panel Meters, Location of Controls and 73
Indicators
Figure C.2 Configuration of Dynamic Range Test 76
Figure C.3 An Example of Dynamic Range Test Results 77
Figure C.4 MDDS Test Configuration 77
Figure C.5 Testing Antenna RF Output Power 79
Table C.1 Location and calibration of Panel Meters 74
Table C.2 Location and calibration of Panel Meters contd. 75
APPENDIX D SCAN STRATEGY IN DOPPLER WEATHER RADAR 81-88
D.1 Basics about scanning strategies employed in DWR operation 81
D.2 Scanning strategies 82
D.2.1 Cone of Silence 83
D.2.2 Operation of Doppler Weather Radars in IMD 84
D.2.3 Present IMD DWR Scan strategy (DWR-Palam) 84
D.2.4 Advantages of Present IMD DWR Scan strategy 85
D.2.5 Scan strategies being followed by IMD for Doppler weather radars 88
Figure D.1 Azimuth Angle 81
Figure D.2 Distance to the Target 81
Figure D.3 Elevation Angle 81
Figure D.4 Plan Position Indicator 82
Figure D.5 Range Height Indicator 82
Figure D.6 Cone of Silence 83
Figure D.7 Present Scan strategy in operation at (DWR-Palam) DWR 84
Figure D.8 Cone of Silence 50.0 km around the radar center 85
Figure D.9 Scan implemented in most of the IMD DWRs 85
Figure D.10 Cone of Silence in Palam-Radar 86
Figure D.11. Cone of silence - Palam Radar Enlarged view 86
Table D.1. PPI and RHI Scanning types 82
Table D.2. Present Scan Strategy at Palam Radar 87
Table D.3. Volume Scan IMD_C 88
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Table D.3. Volume Scan IMD_B 88
APPENDIX E SAFETY AND PRECAUTION SUMMARY 89-94
E.1. General Safety Requirements 89
E.2. Specific Safety Requirements 92
E.3. Antenna /Pedestal Safety 94
95
ANNEXURE 1
Acknowledgements
References
95
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PREFACE
India Meteorological Department is national weather service provider and is mandated
with taking several of meteorological observations, providing forecast and current
meteorological information for optimum operation of weather-sensitive activities. To accomplish
the above activity, department has a vast array of meteorological equipments for observing
meteorological parameters, their analysis and issuing forecast and warnings. Radar network of
IMD is one of the components of observing system which consists of about 40 radars of various
types and vintage. To keep pace with the emerging technologies, department upgrades the
network with instruments of latest technology. IMD has recently procured 12 sophisticated
digital Doppler Weather Radars from M/s Metstar Radar Co. Ltd. China, the first was installed at
DWR Palam, and consequently five more have already been installed at Hyderabad, Agartala,
Nagpur, Mohanbari and Patna and remaining radars are in the process of installation at other
locations.
The Doppler Weather Radars provide information not only on location, intensity
(reflectivity) and movement of the routine and hazardous weather systems, but also on wind
velocity and turbulence associated with them. This information play very important role in
detecting, tracking and monitoring the severe weather phenomenon and issue forecasts and
warning which help the administration in taking timely remedial action.
In Chapter 1, procedure for operation of Doppler Weather Radar, checking of health of
system, configuring and scheduling of scan strategies, generating of various products, checking
various connectivity for data / product, reception and transmission of data / products to central
server and FTP server etc. are described in detail. The maintenance of inventory of spares, log
registers related to fault and action for their rectification and status register are of great help for
maintenance of Doppler Weather Radars in future. The detailed procedure for maintaining these
details in a systematic way has been described in Chapter 2.
Chapter 3 describes miscellaneous activities like sending latest data / products to FTP
server manually in the event of failure of automatic mode of transmission, copying of data /
products on a storage device, searching files, checking of availability of a particular data file and
various other software commands, which are very often required to be performed at the station.
Also the responsibilities of station in-charge and radar operators are given in Chapter 3.
Servicing related to corrective maintenance of the system with the help of Bitex facility is
described in Chapter 4.
To make the document more informative, various figures and tables have been included in
appendices along with the text. Appendices on Overview of Doppler Weather Radar, System
Characteristics of DWR 98 D/S, Calibration procedures, scan strategies in Doppler Weather
Radars and Safety and Precaution Summary have been included for giving a basic idea of the
system for benefit of the readers.
The document has been prepared as maiden attempt in this direction and may require
further up-gradation / modifications as and when suggestions of operating personnel and other
readers are received to make the SOP document more exhaustive and useful.
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INTRODUCTION
The India Meteorological Department (IMD) is catering Meteorological Services and
supporting Research in weather related activities, therefore IMD has the responsibility to
maintain its meteorological instrument network to provide fast and best quality of weather data.
To maintain best quality of meteorological data, a Standard Operating Procedure (SOP) for
operation of each and every meteorological instrument is required. As an attempt in this
direction, this SOP has been prepared for the operation of Doppler Weather Radar WSR 98 D/S
network of India Meteorological Department. SOPs provide consistency in the guidance and so
uniformity in the operations. A number of new radars being installed at various locations in India
by IMD under modernization plan necessitate the formulation of a uniform standard rules and
procedures for operation of DWRs.
This document provides standards and procedures to facilitate the whole process from
switch-ON the Doppler Weather Radar system to generation and transmission of the Doppler
Weather Radar products up to various stake holders. This document was prepared and published
under the auspices of the Office of the DDGM (UI) New Delhi-110003. The purpose of this SOP
is to standardize, as far as practical, the operation of the Weather Surveillance Radar-1998,
Doppler (WSR-98D/S) systems. Some flexibility, under certain meteorological, radar sites, or
mission circumstances is permitted to enhance the quality and utility of some WSR-98D/S
products. The revision process is dependent on the evolution of WSR-98D/S. There are four
numbers of chapters in the document that describe monitoring and documentation of DWR,
additional operational information and maintenance approach of DWR
To supplement this manual five Appendices are also added containing DWR Operational
Information, an overview of Radar, WSR 98D/S characteristics and its capabilities, Calibration
Procedures, scan strategy in Doppler weather radar, safety and precaution summary. The latest
form of this document will also be published in electronic format, and made available on the
website of the office of DDGM (UI), IMD New Delhi-110003, namely,
http://ddgmui.imd.gov.in/ . The SOP will be reviewed and updated periodically based on inputs
from the user and other readers’ group.
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DEFINITION
An important aspect of a quality system is to work according to unambiguous Standard
Operating Procedures s. In fact the whole process from switch on the Weather Radar system to
generation, transmission of the Doppler Weather Radar products up to various stake holders,
monitoring of the system and maintain proper documentation are described in this document.
“This Standard Operating Procedure is the document which describes the regularly
recurring operations relevant to the quality of DWR products and further requirement of
improvements and investigation. The purpose of an SOP is to carry out the operations correctly
and always in the same manner. The SOP must be available at the place where the work is being
done”
The Standard Operating Procedure (SOP) is a valuable tool and worth the preparation
time. An SOP is a guideline that clearly spells out what is expected and required of radar
operators during radar operations or other day-to-day maintenance activities. SOP contains basic
procedural description about methods and also provides details about the appropriate precautions
and safety for operation of radars. The SOPs force a person to think through a procedure step by
step and to standardize the methods. It is also a good training tool and reminder to the staff of the
correct procedure. In some manner SOPs may be required for compliance with regulations.
PURPOSE
The purpose of SOP is to carry out the operations correctly and always in the same
manner. The original SOP should be kept with Deputy Director General of Meteorology (Upper
Air Instruments), New Delhi at a secured place while working copies should be authenticated
with stamps and signature of authorized person must be available at the each Radar Station. SOP
document is a set of compulsory instructions; The competent authority for seeking approval of
any deviations from the given set of instructions or new procedures is Deputy Director General
of Meteorology (Upper Air Instruments), India Meteorological Department, Lodi Road New
Delhi-110 003.
The Doppler Meteorological Radar is a standalone system which detects processes,
distributes, and displays radar weather data. The Doppler Weather Radar uses technology to
acquire particle velocity data in addition to range, direction, and reflectivity data. The Doppler
Weather Radar is a software-driven system. Software processing is used to control the radar
operation according to its characteristics, to produce the optimum radar volume coverage
patterns and to optimize the radar returns. The resulting base weather data is then processed
through the application of meteorological algorithms to generate base and derived weather Radar
products. These products are further processed using graphics algorithms to produce immediate
interpretable weather data displays on color monitors. The Doppler Weather Radar is giving
information on the location, intensity and movement of both routine and hazardous weather
phenomena.
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OBJECTIVES
This document provides a ready reference source for determining the purpose,
physical and functional characteristics, operational capabilities, operating procedures and
limitations of the Doppler Weather Radar equipment. The objectives of this SOP are as follows:
1. To carry out the operations correctly for entire Radar Network of India Meteorological
Department.
2. To set the standards that operators and users will perform under.
3. To provide a good training tool for a new radar operator.
4. To build up a well disciplined environment for a radar operator to work.
SCOPE
What areas of work are to be covered by the procedure?
The areas of the work to be covered by this SOP are operation and maintenance of WSR 98D/S
DW R network of India Meteorological Department. This SOP applies to all radar personnel
throughout India working in WSR 98D/S Doppler Weather Radar network of IMD.
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MONITORING OF DWR SYSTEM
CHAPTER 1
In the process of operation of Doppler Weather Radar, the operator must be familiar with both
hardware and software functions. These two functions could not be exclusively presented
separately in two separate chapters. But, most of the functions regarding hardware are presented
in chapter 1 and software in chapter 3. Initially, safety of personnel and equipment is discussed
in this chapter.
1.0 Safety of personnel, equipment, first aid and emergency rescue
While going to Radome:
Antenna Servo Power and TX Radiation Power are to be put OFF through IRIS MENU
As a safety precaution, the MCB (QF9) & HV in Tx Cabinet is to be switched OFF.
While going to Terrace:
RF Radiation is to be switched OFF through IRIS MENU
1.0.1 Safety Precautions for all the A/C Plants
1. While Switching OFF AC plants trip all associated components of radar which needs
to be operated under optimum temperature.
2. Switch OFF the AC plants/devices.
3. Switch OFF the cooling fan units if not an integrated system with AC compressor.
4. While switching ON the AC plants, the cooling fans will immediately start, wait till the
timer sequence completes in bringing on the Compressor. This indicates the proper
powering ON of AC.
5. Only when Radar room temperature is maintained at optimum values (Around 20 deg
C) radar sub-systems are to be switched ON.
1.0.2 Safety precautions for UPS
1. Ensure Battery voltage is full.
2. Check for battery conditions and sufficient airflow.
3. Have a check on the cabinet and room temperature.
4. During Servicing/ Maintenance of UPS-shut down all loads and gradually increase the
load during startup.
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1.0.3 Safety Precautions for Generator
1. Ensure Fuel Level and pressure for optimum values.
2. Check cooling systems (Water / Air).
3. Always see the startup battery is kept charged and available to start the Generator.
4. Trip down the entire load before bringing up the generator.
5. After optimum speed achieved by the Generator gradually, go on adding the loads. The
thresholds and other settings to above shall be referred to the manufacturer
instructions/ brochure.
1.1. Radar and its equipment switch on procedure
Figure 1.1 Radar Operating Panels
Switching “ON” the radar from cold state for remote operation
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Before controlling radar operations on remote mode using RCP8, radar is to be initially switched
on physically, by the procedural steps in the sequence given below. After performing these steps,
control can be taken by RCP8 with the help of LOCAL/REMOTE button on control panel of Tx
cabinet, to avoid any minor / major breakdown of the system. Power Distribution, RDA and
Transmitter Cabinets can be seen in the above Figure 1.1.
RDA Group Startup Procedure
Keep the "AIR COMPRESSOR" (QF10), the "AIRCRAFT WARNING LIGHT"(QF3)
and RADOME LIGHT (QF2) power on at all times.
Power on the equipment according to the following sequence:
1. Power cabinet: "MAIN POWER SWITCH" (QF1) ON.
2. Power cabinet: Push "Green Button" ON.
3. Power cabinet: “Receiver” (QF7) ON.
4. Power cabinet: "TRANSMITTER" (QF8) ON.
5. Power cabinet: "RDA CABINET" (QF 6) ON.
6. RDA status and control cabinet: "UPS" (A26) ON.
7. RDA Status and Control Cabinet: RVP8 computer ON.
8. RDA Status and Control Cabinet: RCP8 computer ON.
9. RDA status and control cabinet: "DAU POWER" (A2S4) ON.
10. RDA status and control cabinet: "PEDESTAL ELECTRONICS POWER" ON.
11. Transmitter cabinet: "AUXILIARY POWER" and "CABINET LIGHTS POWER"
ON.
12. Monitor the transmitter. After about 13 minutes of pre-heat the "PRE-HEAT" light
will go off and the "airflow" fault lights will illuminate.
13. Transmitter cabinet: “HV POWER” ON.
14. Transmitter cabinet: Push both "MANUAL RESET" and "FAULT DISPLAY
RESET" buttons, observe that the transmitter "AVAILABLE" light is on and the
"Fault" light is off.
15. Power cabinet: “SERVO POWER AMPLIFIER (QF9) ON.
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16. Power cabinet: "RADOME VENTILATION" (QF 5) ON.
17. Run the IRIS/Radar program or IRIS Utilities programs.
Transmitter Cabinet – STATUS LEDs
Figure 1.2 Picture of TX panel showing indicators when radar is in function
NOW the radar is ‘ON’ for operations. All these steps take roughly twenty minutes. Remote
control/operation of radar if required from other servers can be customized to get connected to
RCP8 a job to be performed by network administrator using IRIS / LINUX utilities. As a
general practice it is advised that such provisions shall be avoided unless and otherwise an
absolute necessity. Details can be found in the supplied manuals and is not described here.
1.2. Radar and its equipment switch off procedures
RDA Group Shutdown Procedures
A. Switching “OFF” the radar
1. Run iris in terminal.
MENUSTSC MONITOR Then select task IMD-B, then Select STOP
RIGHT NOW
Select task IMD-C and right click then select STOP RIGHT NOW
MENUSRADAR STATUSnext select appropriate buttons viz.,
(A) RADIATE –OFF (B) T/R POWER-OFF (C) SERVO POWER-
OFF
2. Transmitter Cabinet: "AUXILIARY POWER" OFF.
3. Transmitter Cabinet: "CABINET LIGHTS POWER" OFF.
4. Power Cabinet: "RECEIVER" (QF7) OFF.
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5. Power Cabinet: “SERVO POWER AMPLIFIER” (QF9) OFF
6. RDA Status and Control Cabinet:
RCP8 and RVP8 computers: Exit the operating system and then turn off the power.
7. RDA Status and Control Cabinet: "UPS" (A26) OFF.
8. RDA Status and Control Cabinet: "PEDESTAL ELECTRONICS POWER" OFF.
9. RDA Status and Control Cabinet: "DAU POWER" (A2S4) OFF.
10. Power Cabinet: "RDA CABINET" (QF6) OFF.
11. Transmitter Cabinet: After the transmitter has cooled off (the focus coil is no longer
hot to the touch), Transmitter "HV POWER" OFF.
12. Power Cabinet: "TRANSMITTER" (QF8) OFF.
13. Power Cabinet: Push "Red Button" OFF.
Note:Keep the "AIR COMPRESSOR" (QF10), the "AIRCRAFT WARNING LIGHT"
(QF3) and RADOME LIGHT (QF2) power on at all times.
B. Switching “OFF” the radar during an Emergency
Emergency stop is a mandatory safety measure, for radar operation. This is a switch to stop the
radar suddenly as a life saving measure during sudden accident associated with the radar system
or in case of FIRE. Emergency stop switch is placed in an easily accessible location. Hence, in
case of emergency, such as smoke or visible fire, turn power cabinet “Main power switch” (QF1)
OFF. IF QF1 is unapproachable, the Emergency switch (Diagram shown below Figure 1.3),
fixed in Radar Room at closer approach, shall be depressed in TRIPPING OFF the entire radar
operation
Figure 1.3 Emergency Stop
1.3. Bringing radar to “standby” & reverting (for few minutes)
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STEP I : For stopping the radar up to thirty minutes, HV need not be switched off from the
Tx cabinet, the radar can be taken into local control by pressing the
LOCAL/REMOTE button available in the Tx control panel. Ensure the green LED
at “LOCAL” should glow. Login to RCP8 system, open iris window and connect to
RCP8. Observe the portion of RCP8 read yellow colored highlight after getting
connected.
STEP II : To switch OFF Tasks running:
Run iris in terminal. Select MENUS in iris window.
MENUSTSC MONITOR Then select task IMD-B, then Select STOP RIGHT
NOW
Select task IMD-C and right click then select STOP RIGHT NOW
MENUSRADAR STATUSnext select appropriate buttons viz.,
RADIATE –OFF (B) T/R POWER-OFF (C) SERVO POWER-OFF
1.4. Monitoring DWR system and checking radar status
Ensure the following functionalities.
1. Both of the tasks IMD-C and IMD-B are running properly, clouds and winds are
being shown in real time windows.
2. Check Latest-image folder in operator’s home of IRIS Internet Server whether it is
containing latest images.
3. Ensure power available to the modem and serial router with local lead (line 1) of
MTNL glowing in green color.
4. Products on FTP-server at H.Q and IMD Web-Server (www.imd.gov.in) are getting
updated in time.
5. Check all the A.Cs are functioning o.k. and then alternately switch on the A.Cs which
were shutdown. Also, shutdown the A.Cs which have been functioning till then. By
this way the load will be equally distributed on each A.C.
6. Check whether there are any fault lights glowing on the A1 Panel of UD3 Transmitter
(display panel) and also on the 5A6 Digital Control Unit.
7. Check whether radome light-LEDs are glowing in the Power Control Equipment
cabinet UD98 or not. Also, check whether any abnormal sounds in the Tx system or
antenna assembly.
8. Check UPS system and it’s respective A.Cs.
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9. Checking real time displays:-There are three Icons on Iris Remote Server, “RTD Z”,
“RTD V”, RTD W” double click the icons and their respective windows will open.
If the windows are not opening with double clicking the icons then open ‘terminal’
and type
a.$/usr/sigmet/bin/rtdisp –file RTD_Z&
b.$/usr/sigmet/bin/rtdisp –file RTD_V&
c.$/usr/sigmet/bin/rtdisp –file RTD_W&, (put the window in RHI mode)
Check on RCP-8 in TSC-monitor and ensured both the tasks are running properly.
If the latest images are not available in IRIS Internet Server at
/home/operator/latestimages (or the one which has been configured for such activity),
Go to main server run iris menus product output device product type Headers
onlyselect the productright click under sendselect Station Name in the opened
window. The same procedure should be followed for any product which is not updated in
the latest images.
Whenever any changes are done in the main server, same changes are to be applied in the
standby server.
Example with Screenshot : An example of the above mentioned procedure along with
screenshot is described here. The first window in Figure 1.4 is the real time display of radar
antenna at DWR PALAM with a range of 150 Kms. This range can be selected as 50 kms, 150
kms, 250 kms and 500 kms. This display also gives the information about the name of radar
station, date and time in hours minutes and seconds with two decimal places, elevation and
bearing of the antenna at that particular instant and reflectivity in dBz according to the given
color scale. Color Scale can be selected among the configured color scales. Railroad Overlay is
selected among available overlays for display in real time. The second window in the screenshot
shows practically how to create real time display in the desktop of any server (as given above).
1.5. Precautions for VPN connectivity
Figure 1.4 Creating real time display on desktop of server
7

1. Modem, converter and router are to be kept switched on (24X7) all days. UPS or
generator supply must be connected to power these units.
2. Glowing green LED at the modem (line) indicates VPN line is ‘OK”; at any time
either this green blinking or PMA indicator glows ‘red’, then appropriate action
should be taken with VPN service provider to activate the VPN line at the earliest.
3. During data transmission through VPN, if there is any problem in the VPN line l, call
the principal service provider i.e. M/s Trimax/DataCraft Engineer for earliest
rectification of the fault.
4. For uninterrupted data transmission time to time following observations should be
made, round the clock every now and then
(i) VPN Modem power and line indicator must glow green.
(ii) Network serial router, switch, computer server (Transmission), must be kept
ensured to be working OK.
1.6. Connection among modem ,router and switch box
All these three untis are interconnected as follows: (Indicative in nature varies with make and
type).
1.6.1. L.E.D. illumination status of Modem, Router and Switch box in working condition
Note:
Figure 1.5 Modem, router front side and switch box back side view
1. When VPN connection is o.k, the connected link LEDs i.e No 1 to 7 in the above
picture must always be blinking green. These blinking LEDs are shown in green
background for the sake of clarity, and continuous glowing orange LEDs are show in
orange background.
8

2. In Modem, PMA always shows off when VPN is working in condition. If PMA glows
red, an indication of link problem, power OFF & ON the modem to rule out the
misbehavior of the unit. If problem still persists lodge a complaint with the service
provider and follow up till rectification is done. On case of delay contact to IMD
Telecom section and DDGM(UI) giving the docket number and status for further
action.
1.6.2. Connections of VPN circuit (Example)
Figure 1.6 Modem, Router back Side and switch box front side view
1.6.3. Checking vpn connectivity
Whenever products are not updated in the IMD website, there are two intermediate cases. In the
first case, the products reach up to FTP server, but not up to IMD website.
1.6.3.1. If the products are not getting updated on IMD website only
Case (A): Product Imageries available on ftp server:
make phone call to the Duty officer of DGM Telecom at 011-24693186 or to the one notified.
Meanwhile send the required latest imageries from internet web server to IMD web site,
I.P 125.21.185.11 (or to the one notified) through local scripts (CLI) and continue sending hourly
till VPN is restored.
Case (B): product is not reaching the FTP server
At the Radar main server perform the following
Run iris connect to mainmenus product output window device TRANS_GIF product
type product to be sentselect headers onlyright click under request columnselect Station
name in the opened window and exit. Same to be repeated in standby server also.
Connect it with main, open product output window from the menu and select “headers only”
check which product is not tagged DLH under request column and tag that product as DLH by
9

ight clicking and selecting the Station name with a wild card (Viz for Delhi DLH*, then EXIT,
then FILE and save as DEFAULT. If the RAW data is not being transmitted to the central server
then, go to main server,
Run iris connect to mainmenusopen product output windowselect device as“to
central “select product type as RAWselect product as IMD-Bselect headers onlyright
click under request columnselect DLH in the opened window and exit. Same is to be repeated
for IMD-C, if IMD-C data is not being transmitted.
1.6.3.2. If the products are not getting updated on FTP-server and IMD website
Check whether VPN is OK or NOT physically as mentioned above, VPN connectivity can also
be check with the servers connected with the system through the computer commands i.e.
$traceroute and telnet command. This procedure is given below.
(a)$traceroute xxx.xxx.x.xx (for central server)
(b)$traceroute xxx.xxx.x.xx (for FTP server)
This command can give 30 hops but we have only 6 hops. By checking this command we will
able to know in which junction problem is existing. If VPN is OK, the six hops come as follows:
1. xxx.xxx.xxx.x I.P Address of LAN Gateway (time statistics will be displayed)
2. xxx.xxx.xx.xx I,P Address of Router (time statistics will be displayed)
3. xxx.xx.xx.xxx I.P Address of Radar side VPN MTNL server(time statistics will be
displayed)
4. xxx.xx.xx.xxx I.P Addess of Central server Side VPN MTNL Server (time statistics will
be displayed)
5. xxx.xx.xx.xxx I.P Address of LAN Gateway of Central Server (time statistics will be
displayed)
6. xxx.xxx.x.xx I.P Address of Central server or (time statistics will be displayed ftp server
IPs)
If * * is coming for any I.P. then check each individual IP link with ping command to find
out at what junction the problem is existing.
Note:
Case 1 : if the problem is existing at LAN Gateway, then * * will come after first hop, it means
then there is disconnection at switch. Check all leads of the switch and if there is any loose
contact, it should be fixed properly and the fault may be rectified.
Case 2 : if the problem is existing with ROUTER, then * * will come after ROUTER I.P
Address, then there is discontinuity at router. Check all leads of the router. We can check router
as follows.
10

This can be done by “telnet” command. This command will take us into the root of VPN Circuit
of TRIMAX who is principal service provider of VPN. The company has provided us the id and
password to check the router at our end by User Access Verification procedure as follows. This
is done by giving the command
$telnet xxx.xxx.xxx.x (enter I.P Address of LAN)
When prompted for a password, enter the one associated. Then enable modification by entering
command ‘en’. Again it will be prompted for enable password: enter the root/enable password.
Now it will be in root folder. Issue the command “sh ip int brief” (for seeing the IP protocol
information in brief).
The following exercise is given on the basis of actual commands or information and the
operators are required to verify the status of the router. If Fast Ethernet 0/0 down then check
MODEM lead or If serial router 0/1/0 is down then check all leads of the router also.
EXAMPLE No. 1
operator@DELHI-INTERNET ~]$ telnet router-ip [example: 192.168.50.1]
Trying router ip...
Connected to router-ip.
Escape character is '^]'.
User Access Verification
Password: passwd
IMD_Radar_NDLS>en
Password: enable-passwd
IMD_Radar_NDLS>sh ip int brief
Interface IP-Address OK? Method Status Protocol
FastEthernet 0/0 router- ip YES NVRAM up up
FastEthernet 0/1 unassigned YES NVRAM administratively down down
Serial 0/0/0 WAN-ip YES NVRAM up up
Case 3 : If the problem is existing at WAN then * * will come after WAN-ip (MTNL Server at the
end of radar side) then book the case with 1506 (Local MTNL/Service provider).
Case 4 : If the problem existing on Other side of the WAN (MTNL server at the end of H.Q then
** will be displayed after HQ-WAN-ip in such a case book the complaint with Mumbai Trimax
(022-4068). Provide them the I P address of central server or ftp server (which is not pinging due
to VPN connectivity problem) and the station contact phone number. Mumbai VPN office
(phone No’s: 022-040680001,022-406813339) shall also be approached obtain the complaint no.
from them and record the complaint No., Date and time in complaint –book.
1.6.4. Logical flow diagram for cheking vpn connectivity
11

CHECKING VPN CONNECTIVITY
YES
Ping 192.168.2.75
and 192.168.2.76
NO
DATA
LOSS
>20%
YES
Call
MTNL/TRIMAX
exchange to check
MLDN ID of VPN
( DWR PALAM VPN-9081)
PINGING
Ping local
LAN and
router IPs
NOT PINGING
PMA light will be
“RED”
Traceroute
192.168.2.75/76
Serial status is
“down”
Check with
“telnet”
Fast ETHERNET
status is
“down”
NO
VPN
‘OK’
MLDN Of
VPN is
“OK”
NO
CALL “HQ” TO
CHECK THEIR
SIDE
YES
Route is
clear upto
172.50.16.174
“HQ” side is “ok”
Check all cables of
MODEM and
OFF/ON power
switch
Book the
complaint at
TRIMAX
/MTNL(1918) by
giving the circuit
no. 027177) and
take the Com.No.
Check all cables of
ROUTER and
OFF/ON power
switch
PMA
red light gone
NO
YES
Figure 1.7 Logical steps for checking VPN connectivity
EXAMPLE No. 2 : This example is to check whether products are transmitting to ftp
server at DGM (TELECOM) or not ?
[operator@DELHI-REMOTE ~]$ ftp 192.168.2.75 (remote-ip)
Connected to 192.168.2.75 (192.168.2.75).
220 (vsFTPd 1.2.0)
Name (192.168.2.75:operator): username [Refer to the username supplied to the station]
331 Please specify the password.
Password:password [Refer to the password supplied to the station]
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp>bin
ftp> ls
227 Entering Passive Mode (remote-ip)
150 Here comes the directory listing.
-rw-r--r-- 1 0 0 84091 Jul 12 02:33 caz_dlh.gif
drwxrwxrwx 14 530 508 258048 Jul 01 05:02 chn
12

drwxr-xr-x 3 501 500 4096 Aug 10 02:39 del
drwxrwxrwx 4 529 529 90112 Jul 01 05:02 kol
drwxrwxrwx 4 500 530 380928 Jun 27 2009 mpt
-rw-r--r-- 1 501 500 110259 Aug 13 13:13 pac_dlh.gif
drwxrwxrwx 12 502 505 4096 Feb 16 03:45 srk
drwxrwxrwx 4 531 531 4096 Jun 23 04:17 vsk
226 Directory send OK.
ftp> cd del
250 Directory successfully changed.
ftp> ls
227 Entering Passive Mode (remote-ip)
150 Here comes the directory listing.
-rw-r--r-- 1 501 500 73052 Aug 14 17:59 caz_dlh.gif
-rw-r--r-- 1 501 500 109532 Aug 14 02:39 pac_dlh.gif
-rw-r--r-- 1 501 500 141523 Aug 14 18:00 ppv_dlh.gif
-rw-r--r-- 1 501 500 140087 Aug 14 17:53 ppz_dlh.gif
drwxr-xr-x 2 0 0 4096 Jul 02 02:40 previous
-rw-r--r-- 1 501 500 110685 Aug 14 18:01 sri_dlh.gif
-rw-r--r-- 1 501 500 111973 Aug 14 18:01 vil_dlh.gif
-rw-r--r-- 1 501 500 11629 Aug 14 18:01 vp2_dlh.gif
226 Directory send OK.
1.7. To get back the products which are received at ftp server
After getting connected to ftp server, proceed as given below with the following commands.
ftp> mget *.*
mget caz_dlh.gif? y
227 Entering Passive Mode (remote-ip)
150 Opening BINARY mode data connection for caz_dlh.gif (73052 bytes).
226 File send OK.
73052 bytes received in 2.46 secs (29 Kbytes/sec)
mget pac_dlh.gif? y
227 Entering Passive Mode (remote-ip)
150 Opening BINARY mode data connection for pac_dlh.gif (109532 bytes).
y226 File send OK.
109532 bytes received in 3.77 secs (28 Kbytes/sec)
mget ppv_dlh.gif? y
227 Entering Passive Mode (remote-ip)
150 Opening BINARY mode data connection for ppv_dlh.gif (141523 bytes).
226 File send OK.
141523 bytes received in 4.69 secs (29 Kbytes/sec)
mget ppz_dlh.gif? y
227 Entering Passive Mode (remote-ip)
150 Opening BINARY mode data connection for ppz_dlh.gif (140159 bytes).
226 File send OK.
140159 bytes received in 4.66 secs (29 Kbytes/sec)
mget sri_dlh.gif? y
13

227 Entering Passive Mode (remote-ip)
150 Opening BINARY mode data connection for sri_dlh.gif (110685 bytes).
226 File send OK.
110685 bytes received in 3.93 secs (28 Kbytes/sec)
mget vil_dlh.gif? y
227 Entering Passive Mode (remote-ip)
150 Opening BINARY mode data connection for vil_dlh.gif (111973 bytes).
226 File send OK.
111973 bytes received in 3.75 secs (29 Kbytes/sec)
mget vp2_dlh.gif? y
227 Entering Passive Mode (remote-ip)
150 Opening BINARY mode data connection for vp2_dlh.gif (11629 bytes).
226 File send OK.
11629 bytes received in 0.575 secs (20 Kbytes/sec)
ftp> bye
1.8. Copying raw data from a server to any workstation of any date
[operator@DELHI-REMOTE~]$scp -r main:/usr/iris_data/product_raw/XXX(i.e
DLH)YYMMDD*.* workstation-name:/usr/iris_data/any-folder
1.9. Configuring and scheduling of a scan strategy
A radar task is the scan configuring procedure, by giving appropriate specifications of PW, PRF,
Phase coding, etc as well as signal qualifiers, clutter filters etc. IRIS radar license is a must
before configuring a radar task. Normally Analysis system (Main & Standby) has most of the
licenses incorporated. As per the orders of Radar Lab, DDGM(UI), at present, two common
tasks are performed by all IMD radars, viz., IMD-B and IMD-C. IMD-C is a surveillance scan
with two elevation angles 0.5degree and 1.0degree with a lower PRF (300Hz) with a scan range
of 500 km. The basic moments are restricted to Reflectivity as multiple folding may occur in
other moment fields. IMD-B is the volume data scan with ten elevation sweeps, operated at Dual
PRF mode of 600/450Hz. The following steps enables one to create an initial scan strategy/Task.
STEP 1 : Invoke “iris” though terminal to get the IRIS window
14

Figure 1.8 Connecting to MAIN server
STEP 2 : Select rcp8 [to connect to the RADAR system]
Figure 1.9 Clicking pull-down Menus
Figure 1.10 Window after connecting with RCP8
15

STEP 3 : Click Task configuration in Menus
Figure 1.11 Window of task configuration
STEP 4 : After completion of the task configuration, select Task monitor, schedule the
appropriate repeat time and conFigure the time to start this task. Then one can select it
to be scheduled for continuous running (As shown below). During the process at any
time if doubt exists, the Help option in the window, can be accessed, which opens the
appropriate related PDF documents.
Figure 1.12 Scheduling task
16

Thus now the tasks are configured and scheduled. Any time a scheduled task can be
stopped by right clicking over command area and selecting Stop. Actual scan
strategies followed at DWR PALAM can be seen in D.2.4.5 of APPENDIX D.
1.9.1. Checking whether new scan strategy is working
The newly scheduled scan strategy can be checked by a simple command “productx product
name”. This command when applied to a raw/basic/derived product, it will show all details of
that product, e.g., the server from which it is derived, from which task it is generated, what is
THE PRF,FREQ., and wavelength, at that time, melting level height, power, band width, and
noise of the transmitter, Rx bandwidth, Scan type, Scan speed, Height of radar a.m.s.l: F.,
Processing Mode FFT, Thresholds of different parameters, no. of sweeps, each having 360 rays
and no. of bins and Angle list.
Example for new scan strategy :
[operator@DELHI-STANDBY ~]$ productx DLH100819073440.RAWPRTY
------------- Product Summary for DLH100819073440.RAWPRTY -------------
Ingest site name : 'DWRDELHI(PALAM)', Version: 8.12
Ingest hardware name: 'DWRDELHI(PALAM)'
Product site name : 'DLH-STBY-PLM', Version: 8.12
File size: 3735552 bytes (Disk space: 3735552 bytes)
Product type is: Raw Data
PCO name: IMD-B, TCO name: IMD-B
PRF: 600/450Hz, Wavelength: 10.62cm, Nyquist: 47.79m/s(V), 15.93m/s(W)
XMT Polarization: Horizontal, Wind:???
Constant:67.42 dB, I0:-113.20 dBm, Cal Noise:-81.99 dBm, Bandwidth:0 kHz.
ZFlags: SP_T, block_zc, attn_zc, target_zc, dpatten_zc, dpatten_z
VFlags: SP_V, 3lag_w, ship_v, unfold_vc, fall_vc, storm_vc
Heights: Radar: 235m, Ground: 216m, Melting: 5400m MSL
Maximum range: 249.8 km
Ingest time: 07:34:40 19 AUG 2010 UTC (0 minutes west) DST:0/0
Volume scan time: 07:34:40 19 AUG 2010 UTC (LT: IST -330 minutes)
Oldest Ing time: 07:34:40 19 AUG 2010 UTC
Product Gen time: 07:41:35 19 AUG 2010 UTC
Input count: 1
Product is not composted.
Full volume scan, Force 8-bit, Selected data recorded
Information from INGEST Header
------------------------------
17

Site name: 'DWRDELHI(PALAM)', Task name: 'IMD-B'
Scan: PPI, Speed: 12.00 deg/sec, Resolution:1.00 deg
Description: 'Copy of IMD_B scan performed on Gematronik radars'
Location: 28 33.6'N 77 4.3'E, Altitude: 235 meters, Melting height:5400 meters
Dpolapp config:
Volume Time: 07:34:40.754 19 AUG 2010 UTC (0 min. west) (LT: IST -330 min.)
ZFlags: SP_T, block_zc, attn_zc, target_zc, dpatten_zc, dpatten_z
VFlags: SP_V, 3lag_w, ship_v, unfold_vc, fall_vc, storm_vc
PRF: 600/450Hz, PulseWidth: 1.00 usec (0)
BeamWidth: 0.93/0.93 deg.
Radar constant: 67.42/67.42 dB, Receiver bandwidth 0 kHz.
Calibration I0: -113.20/-111.45 dBm, with noise -81.99/-75.34 dBm.
LOG-Noise: 0.2158, Lin-Noise: 0.2158, I-Off: 0.0000, Q-Off: 0.0000
SOPRM Flags: 0x04a7, LOG Slope: 0.480, Z-Cal: -45.81dBZ, H/V: 0.00 dB
Filters: Dop:6, Log:0; PntClt: 2, Thresh: 6.0 dB; Samples: 70
Processing Mode: FFT, Xmt Phase: Random
Zdr Threshold: LOG
GDR = 0.00 dB, XDR = 0.00 dB
T Threshold: LOG LOG = 2.0 dB
Z Threshold: SQI & LOG & CSR SIG = 5.0 dB
V Threshold: SQI & CSR CSR = 20.0 dB
W Threshold: SIG & SQI & LOG SQI = 0.35
Available moments are: dBZ V W
Original moments were: dBT dBZ V W Vc
Starting range 2.000 km, range bin spacing 250 meters
There are 12 sweeps, each having 360 rays and 992 bins
Angle list: 0.5 1.4 2.3 3.3 4.2 5.5 7.0 9.5 12.5 17.5 24.5 35.0
1.10. Procedure for generation of DWR products
Configuring IRIS products
Configuration of IRIS Meteorological Products using the product configuration menu: IRIS lets
create products for a wide variety of applications, e.g., base and derived products, aviation
products, rainfall products (hydrological products), warning products, etc. This product provides
information that can be used by weather forecaster for weather now-Casting and forecasting.
Most product configuration menus have the same general format, though some of them are
different. Generally Product Configuration procedure can be divided into Four Parts as follows:
18

STEP 1 : Invoke “iris” though terminal to get the IRIS window.
Figure 1.13 Opening iris and configuring a new product
STEP 2 : Select Main/Standby. Go in Menus for Product configuration as shown above.
STEP 3 : Product configuration : In this window as shown above, there are many products that
can be generated in the button Type, select the appropriate product under Type and do the
configuration settings. Help option in the window can be accessed which opens appropriate
related PDF documents enabling configuring a product of your choice. Give the parameters of
your choice and save that product with a name which can be recalled when product scheduler is
opened later, as given below. If this saving is done with a name that can enable in identifying by
its use or by settings, it is helpful in recalling. This entire procedure is shown in a flow diagram
on next page.
Figure 1.14 Saving new product with a name
19

irisConnectmenusProduct Configurationselect parameterssave the file
STEP 4 : Product Scheduler Menu : Once a product is configured , the appropriate product file
is to be scheduled for generating outputs. Hence, the product scheduler menu is opened, and as
it contains a list of several saved products available on the system, the required product to be
scheduled is to be selected from the list of the pop-up window that appears by right-clicking on
the product header line below ‘site’. As we add products (already configured in Product
configuration and saved) to the Scheduler, they are placed under the appropriate header
according to the type of product. Hence, they can be recalled from the same header (line).
Hence, the window with the header file Max products is selected initially as shown in the above
diagram. Then, the particular product, V_250KM (in our case) is to be selected. Later, select the
date and time from which the product is to be scheduled.
Figure 1.15 Scheduling the configured product
STEP 5 : Time Scheduling operates under the concept NEXT-DATA-TIME : NEXT
corresponds to the time in hours, minutes, date, month and year from which our generated
product should start collecting data. To set the time, position the mouse cursor over the Next-
Data-Time field and right click to get pop up time menu. Use the plus and minus buttons to
increase and decrease the hours, minutes, day, month or year as per the requirement, than press
OK to exit from the window. The time we specify here is the time from which the product is to
be generated. This time is recorded in the field as given in the Figure above.
20

STEP 6 : Skip time : This is the time for which the task should skip processing the data. This
skip time is used only particular type of products like pac, which collects accumulated rainfall
for only a particular period. For all other products, the default value of the Skip field is “00:00”
indicating no TASKs should be skipped as shown below.
Figure 1.16 Skipping the processing
Next is Request FieldAll, all associated TASK data collected after the next data time are
processed.
21

Figure 1.17 Processing all selected tasks
This procedure is shown in the flow diagram below.
irisConnectmenusProduct SchedulerNext-Data-TimeSkip TimeSelect All
starts running Wait
Figure 1.18 Generated new product
The product is generated on an on-going basis Whenever the TASK collects data, subject to the
skip time. The status field shows the current status of each product. The Running shows
product is being generated. After product has completed, the status changes from Running to
Wait. Now, scheduling is completed.
1.10.1. Adding, removing scheduled products
Irisconnectmenusproduct schedulerRight click headerselect newly configured
product addfilesave as
To add /Remove a product to the Schedule:
1. Select the header for the type of product you want enter or any product of that type.
2. Position the mouse cursor over the product field and choose Add/Remove from the
pop – up menu. IRIS then displays a list of Product of that type. (already configured
in Product configuration and saved). Select a product, and it is added to the schedule.
If you do not want to add any of the products in the list click on the cancel button.
1.10.2. Editing the product configuration of the schedule products
1. Select the product you want to edit.
2. Position the mouse cursor over the product field and choose edit from the pop-up
menu. IRIS opens the product configuration menu with the selected product loaded
into it.
22

3. Edit the Product as needed , then Choose File Save as to Save changes.
4. Exit from the product configuration menu. IRIS returns you to the product Scheduler
menu. Your changes (changed file name) should be reflected in the product schedule
fields.
5. Add edited product in scheduler.
Irisconnectmenusproduct scheduler select scheduled producteditfilesave
as
1.10.3. Scheduling and stopping PRODUCT GENERATION
1. Select the product that you want to schedule for generation
2. Set the Next-Data-Time and Skip Fields. These Two fields determine when TASK
begins and how frequently the product is generated.
3. Position the mouse cursor over the request field and choose “All” from the pop-up
menu.
4. We can generate products from either future or past TASKS by adjusting the Next-
Data-Time.
Operator ] $ iris ->Connect->menus->Product Schedulerselect edited productNext-
Data-TimeSkip TimeSelect All starts runningWait
1.11. How to see other radar site archival raw data at your local computer
Copy other Radar site Raw data to local computer /usr/iris_data/product_raw use productx
command to open the raw data, get the site name information setup General “List of
Radar Site Names and Site Codes” add a new site name use the name you get from raw data
give the Code save &exit ; (If not do up configure, default will use XXX as site Code)
qiris siris Product Outputfind the raw data reingest Product ConfigSelect product
type and task name to configure your product Save Product Scheduler Display Add
for Right Click the product type header add your configure product name Right Click the
new come line(your configure product) on the “Next-Data-Time” column Select the before
time Right Click the “Rqst” column select All To Quick Look window you can select
your product to see/confirmation.
1.12. Uploading of products on India Met. Department’s website
The Doppler Weather Radar products in image form (gif format) are uploaded to IMD website,
the original product image files are re-named as follows before uploading to IMD website.
Plan Position Indicator – Reflectivity (PPZ)
Plan Position Indicator – Velocity (PPV)
as ppz_stn.gif
as ppv_stn.gif
23

Plan Position Indicator – Close range (PPI)
Plan Position Indicator – Surface Rainfall Intensity (SRI)
Plan Position Indicator – 24 Hr Preci. Accumulation
Maximum Reflectivity (MaxZ)
Vertical Wind Profile (VVP2)
Stn = station name (ex : dlh for NEW DELHI)
as ppi_stn.gif
as sri_stn.gif
as pac_stn.gif
as caz_stn.gif
as vp2_stn.gif
1. The renamed images are uploaded to FTP server at DGM (TELECOM), New Delhi
I.P 192.168.2.75, working on latest and faster Virtual Private Network (VPN).
2. The same images are THEN uploaded from FTP server to IMD website server with
I.P 125.21.185.11 at DGM (TELECOM) RTH New Delhi, using a local network
connection.
3. The uploading is done automatically every 10 minutes using VPN and FTP script
files.
1.13. Sequence of actions in case of radar breakdown
Action to be taken by duty asstt. before radar being stopped for maintenance or whenever radar
breakdown occours, or whenever Radar is to be stopped TEMPORARILY.
IMPORTANT :
(A). After Shutting down the Radar following Procedure has to followed
(i)
Request to Issue “NOTAM” from concerned ATC Duty Officer.
(ii) Put the appropriate Radar Stop message on the ftp server (IMD-HQ) which will display this
message in place of Radar products on IMD website.
(iii) Regarding the shutting down of radar with TIME, DATE and CAUSE for shutting down the
Radar, Immediately, E-mail should be issued to the following concerned authorities/officials.
(i) DDGM(UI)
(ii) SC. (E) In-Charge Radar Lab, DDGM (UI)
(iii) DWR In-Charge
(iv) M/s SGS Weather, if necessary
(v) Put a note in T- Log regarding the shutting down of radar by mentioning TIME,
DATE and expected time of restarting.
(B). After starting the radar following Procedure has to be followed
(i)
Request to cancel the “ NOTAM” from concerned ATC Duty Officer
(ii) Regarding the starting of radar with TIME and DATE immediate E-mail should be issued to
the following concerned authorities/officials.
(i) DDGM(UI)
24

(ii) SC. (E) In-Charge Radar Lab, DDGM (UI)
(iii) DWR In-Charge or any other concerned In-Charge of Doppler Radar Station
(v) M/s SGS Weather, if necessary
(vi) Put a note in T- Log regarding the starting of radar by Mentioning time and date.
1.14. Standardizing a product
Archiving old data corresponding to a past special weather event and generating new
products for validating the radar products.
Suppose we need to get raw data of the period 03-07-2010 to 08-07-2010.The raw data product
generates a compressed product file containing all of the signal processor data parameters
collected during the selected task. As the raw product cannot be displayed, but it can be archived
to tape or sent to another IRIS analysis system in network. Once these raw products
corresponding to the above period is selected and reingested, ingest files are created, so that
products images can be generated in the other server for analysis or testing for standardization.
Procedure:
Irisconnectlocal host (remote or internet server)menusdeviceldasite type raw
give wild timegive date month and yearfiles wildmountcommandretrivewatch files
being retrivedcommandreingestsee files being reingested
Configure the required product, say, TS-100, for the same period, i.e., 03-07-2010 to 08-07-
2010, and schedule it. The TS-100 products can now be seen in quick look window. Now, if the
TS-100 is not reflecting the warning time correctly, change one or three parameters of TS-100
and generate again with another name till it represents the thunderstorm time and intensity
perfectly. Then the product TS-100 is said to be validated with the new name.
25

DOPPLER WEATHER RADAR DOCUMENTATION
2.1. Routine documentation work
CHAPTER 2
IMPORTANCE: For smooth operation and maintenance of Doppler Weather Radar at the site,
it is necessary to maintain proper detailed documentation encompassing all aspects, such as
procedures to be followed for diagnosis of faults, step-wise procedures for rectification, details
of significant weather events to be recorded from nearby surface observatory and actual realised
features in the products. This also accounts for continuous performance of the system. The
documentation will provide the history of a particular problem being repeatedly encountered, and
indicate the best possible solution to solve the problem. Following detailed documentation are to
be maintained at each radar site as part of operational practices.
(i) Working status of DWR systems as a whole: This should be checked daily in the early
morning at (0830 IST) and the status is to be updated online in the designated web pages. If any
problem is reported, the action taken by the duty assistant of the DWR Station should also be
indicated in the status report. This information should be delivered to the Office of DDGM (UI),
New Delhi, which is the Technical and Operational Coordinator for the observational RADAR
network of IMD. If problem persists, appropriate action to be taken by the officer In-Charge of
the station with the consent of DDGM (UI), New Delhi.
(ii) Mission summaries for future course of action : The In-charge of Radar Lab, DDGM (UI),
NEW DELHI along with In-Charge of respective Radar Station, who is the Coordinator and
responsible for smooth functioning of IMD Radar Network all over the country, will prepare a
consolidated report / summary and approved by DGM, for further course of action. This may be
done fortnightly/monthly on the basis of daily status reports. Radar scientists/experts must
contribute their valuable suggestions to help or to solve the problems for smooth function of
IMD Weather Radar network. There are ten Registers/Logs to be maintained by each and every
Radar station. The list and period of updation of each register is given in the following Table 2.1.
S. No. Name of the Document Period of updation
01 Radar status register To be updated hourly
02 Fault log book To be check daily and updated accordingly
03 Communication
Complaint Book
To be checked daily and if any complaint is there, follow up
action is to be taken till rectification of problem.
04 T-log book To be checked daily and logs to be written
05 A-log book To be checked daily and logs to be written
06 Spare parts register To be filled if any spare of Radar is replaced/consumed.
07 Event log book To be filled in case of significant weather exists
08 Notam-information to To be filled whenever radar is stopped and restarted.
the designated office
09 VPN Connectivity To be filled whenever VPN complaint is booked
Status
10 E-Mail Register To be filled whenever any mail is sent by the respective radar
26

Station and print-out (except Daily Status Report) to be taken
and put it in E-mail printout Register
2.2. Lists of the documents
2.2.1. Radar status register
All entries in this register are to be updated hourly. Real time display of DBZ, V, W, Antenna
Sweep,AZ, and EL to be monitored for any abnormalities. Appropriate entries in the respective
columns of the Logbook to be made. Clouds and wind observed in the DWR products also are to
be reported hourly in this register. If ground clutter is not observed, suitable entries in column
no.9 of table 2.2 to be made. The latest products available in the ftp server should also check.
The time of the products observed in the ftp server and the time in IST at which these latest
products are checked should mentioned in the 8 th column.
Table 2.2. Radar status register
Date /
Time
(UTC)
DBZ
V
W
Clouds
Wind
Ant.
Sweep
and EL
updated images time in
website/Latest time
of generated products
in QLW in UTC
Ground
Clutter
Checked
VPN
Connectivity
Contacted
DGM (Tel.)
If ftp is not
Connected
Products
Sent thro.
CLI mode
(if VPN
Failed )
Remarks
Sign
of
D.O
Sign.
of
I/C
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
If ftp server is not connecting, Duty Officer, DGM (telecom) to be contacted over phone (phone
NO.24693186) for intimating about ftp server not connecting / pinging. Check the VPN
Connection through trace route command for concerned server I.P Address, (172.xxx.xxx.xxx).
If data is being transmitted in 3 hops, i.e., modem I.P, Router I.P, and MTNL I.P., it can be
concluded that connectivity exists from DWR PALAM side for VPN (kindly REFER 1.6.3
of CHAPTER 1). The result is to be entered in column no.10. Also, enquire whether there is any
problem associated with ftp server or the VPN Connectivity i.e. from DGM (TELECOM) side of
VPN circuit. Entry may be made in column no.11 and all seven products are to be copied into a
pen drive and pasted in C: drive of INTERNET PC (in workstation room) from
/home/operator/latest images of INTERNET SERVER (WEB-SERVER). These seven pictures
are to be sent to IMD website (125.21.185.11) through internet connection using CLI mode, as
given in 3.1 of CHAPTER 3 and entry should be made in column no.12.
27

2.2.2. Fault log book
In this logbook, entries are to be made as per Table 2.3 whenever the radar is stopped due to any
fault in the Radar. The time of stopping and the reason for stopping is to be mentioned.
Whenever radar operation is restored, the time of restoration and period of stoppage. The
information about the NOTAM issued or not, is to be recorded in the column no.8. Software
problems need not to be reported in this book unless the radar is stopped.
Table 2.3 Fault log book
S.
No.
Date
Nature of
Fault
Indication in
the system
Reported
at (UTC)
Informed
to SGS at
(UTC)
Fault
rectified
at (UTC)
Fault period
If NOTAM
issued
Spare
Used
Sign.
of SGS
official
Sign.
of
D.A
Sign. Of
A.M.
DWR
Sign.
of
Dir. DWR
Remarks
2.2.3. Communication complaint book
In this register, the respective Duty Asstt. should make entries of the complaints regarding the
communication problem associated with MTNL local line and Internet problems. They have to
specify the time and date of lodging of the complaint along with other details as per following
Table 2.4.
Table 2.4 Complaint book
S.NO. DATE COMPLAINT No. PROBLEM IN DETAIL SIGN OF D.A. SIGN OF AM
2.2.4. T-log book
This T-logbook is to be maintained for Technical information. It has details of every technical
problem encountered, with the purpose of recording the history of each hardware and software
problems. This can be used as a source for guidance during fault identification/rectification and
also for preparation of statistics of specific problems which are encountered repeatedly. Entries
in detail should be made in T-LOG BOOK, whenever any software or hardware servicing is
done. This logbook must contain the full details i.e. the name of the panels in which servicing
was carried out, the PCBs that were checked by the service engineer, either by resetting or
replacing by new PCBs from stores, the test and measuring instruments that were used, the
measurements that were taken with its magnitude and units of the parameter, the adjustments that
were carried out either in the panel meters, or in any PCBs, the faults that were traced out and the
line of action taken by the service engineer for rectification of the problem. The date and time
while servicing was done is also to be mentioned. As a whole, this report must comprehensive &
self sufficient to explain the technical changes that were undertaken during the duty time. It is
mentioned here that after rectification of problem all the outputs of radar should be checked, if
any discrepancy found, it is to be recorded with further course of action.
28

2.2.5. A-log book
Details of all administrative problems / information regarding leave, duty arrangement or any
instruction issued over phone by higher officials which are to be communicated to all concerned
officials, for smooth functioning of administration.
2.2.6. Spare parts inventory
Whenever any spare part of Radar is replaced/ consumed from the existing stock by M/s SGS or
M/s METSTAR Service Engineers or any other official, information should be recorded in this
register as shown in Table 2.5 along with proper receipt of U/S item which should be taken from
concerned engineer, mentioning the name of the item, Serial. No., Part No. etc. Spares are to be
replenished with new spare by them within 15 Days of replacement time and to be recorded in
the Logbook with all relevant information. An official letter must be issued to concerned party/
firm/ supplier. This register must be checked once in a month i.e. on the first day of every month.
Table 2.5. Spare parts register
S.
No.
Date
Spare
used
With
S.no.
Defective
spare
Received with
S.no.
Replacement received
from SGS with
S.no. and
Date
Opening stock
Balance
Current
Stock
Position
Sign
of
A.M
Sign.
of Dir. DWR
Remarks
2.2.7. Event log book
Whenever any significant event occurred around the station like SQ, DS, TS/TSRA, Hail etc, the
time of commencement, cessation and the period of persistence should be recorded in the
following Table 2.6. Details can also be taken from concerned forecasting office or from
Departmental Website.
Table 2.6 Event log book
S.
No.
Date
Time
From-To
(UTC)
Type of
Weather
event
Period
(In
hrs:min)
Folder of events for all types
Of product pictures and
details if any
Sign. Of
D.A
Sign. Of
A.M DWR
Sign. of Dir.
DWR
Remarks
(1). Various related products generated for the above event, time period, date and time of the
event are to be collected and kept in a folder with proper identification. This is to be brought to
the notice of all operators and In charge.
(2). Suppose, the event is TSRA. The concerned product is a WARN product named TS-250 or
TS-150 or TS-100 or THUNDERSTORM or MICROBURST and the raw data used in the
product generation, the product files for these warnings should be archived with backup. The
operator should varify the date and time of the warning and assess the reflectivity values vis a vis
intensity of thunderstorm occurred at the station.
29

(3). Also, if any of the above warn products do not correctly represent the occurred
phenomenon, a new WARN product is to be configured with variation of parameters to
correctly represent the event and see that the newly configured product is representing all
features of the event.
(4). In spite of configuring and generating the new product, if the occurred event was not fully
represented by it, explanation is to be given in detail as to what features are matching in that
product, and what features are not matching along with the reason for not matching.
(5). Suggestions may be given to modify the parameters of the respective product to fully
reflect the features of the weather event with full discussion of the earlier and new product
with variation of parameters and the acceptability of the resulting product.
(6). Another product i.e. WIND / MAX Z / SRI / PPV may also be taken for validation for the
same event while following the above five steps, and final report of each event-study should be
submitted to the in-charge of the station.
(7). Every month, a consolidated report of all Significant Weather Event Study-Report is to be
prepared for record, future reference and for DWR product evolution also.
2.2.8. Notam-Information to NTC : The massage of “Radar under maintenance” in the JPG
format of to be transmitted on ftp server for display on IMD Website immediately and intimate
to DDGM (UI) and DGM (TELECOM) through e-mail as well as telephonically. Permission is
to be taken from the Director I/C before issuing the NOTAM (Please refer 1.12 of Chapter 1) for
all occassions when radar was stopped for a period of more than 1 hour, due to any reason i.e.
technical breakdown/ other reasons like civil or electrical related work. Information to issue the
Notam must be given to NTC (to Batch in-charge at ATC) and all respective entries should be
made in the Table 2.7 of NOTAM REGISTER.
Table 2.7 Notam register
S.
No.
Time of
DWR
Breakdown
Specific
Tech.
Reason
DWR Time of DWR
stopped except became ok
technical
resons
NOTAM
Issued for
the period
From To
Name of Batch
Incharge at
NTC
Name
of
D.A
Sign.
of
D.A
Sign.
of A.M
DWR
Sign. of Dir.
2.2.9. VPN connectivity status
This Logbook in the following tabulated format is to be maintained whenever VPN complaint is
booked. The details of VPN connectivity problem must be mentioned in VPN connectivity
status report & VPN Connectivity Status Table 2.8 given below mentioning the cause of
problem also. VPN status can be checked by the procedure mentioned in the Logical flow
diagram. Please Ref. 1.6.3.2 of chapter 1.
30

Table 2.8 VPN connectivity status
S.
No.
Dated
Time of VPN
Connectivity
failure(UTC)
Time of VPN
Connectivity
Restored(UTC)
reason for
failure
Complaint
No.
Name of
TRIMAX
Personnel
Action for
early
restoration of
Sign.
of
D.A
Sign of
AM
Radar
2.2.10. E-Mail register
This is to be maintained whenever mail is sent through DWR Palam e-mail ID
palam.radar@yahoo.co.in or dwrpalam@gmail.com, and print-out (except Daily Status Report)
is to be taken and kept in E-mail folder after recording the details in the following E-mail
Register Table 2.9.
Table 2.9 E-mail register
S. Date Subject Sent to Received from Action Remarks
No.
2.2.11. Other important works related with DWR operation
Radar Status Report is to be sent on routine basis, every day in the morning, by Duty
Assistant at 0900hrs IST, through emails radarstatus@gmail.com to In-charge of Radar Lab,
DDGM (UI) New Delhi and to respective In-charge of DWR station and other concerned
officials. This should be updated on DDGM (UI) websites (http://ddgmui.imd.gov.in) also. For
display of maintenance of radar and servicing information over website, “shell program”
designed in the Iris Main Server is to be double clicked. Whenever Radar is to be stopped for
servicing or otherwise for duration more than one hour, AM (Radar) and Director I/C of the
Station. are to be informed along with concerned duty officer of the respective Meteorological
Office, to issue the NOTAM.
31

ADDITIONAL OPERATIONAL INFORMATION
CHAPTER 3
3.1. Procedure to send latest products direct to IMD website manually, whenever VPN
connectivity fails
The procedure to be followed whenever VPN is totally or partially down with packet loss more
than 50%.
1 Copy the seven products from/home/operator/latestimages folder
2 Paste them in C: drive of windows XP computer connected with internet facility.
3 Send them to I.P address 192.168.2.75 through command line by giving proper IP address
of IMD website.
Step-I. Copy the seven products from IRIS INTERNET WEBSERVER
Products which are regularly getting updated are:
2. caz_dlh.gif,
3. pac_dlh.gif,
4. ppz_dlh.gif,
5. ppi_dlh.gif,
6. ppv_dlh.gif,
7. sri_dlh.gif,
8. vp2_dlh.gif,
Procedure to copy these images on to a pen drive from the latest images folder of operator's
home of INTERNET SERVER are as follows:
(1) Login as super user by giving command: su - and password as xxxxxxxx
(2) Insert the pen drive and give command fdisk -l and then the vacant mount point will be
shown as /dev/sdb1 or /dev/sdb2 or dev/sdb3.
(3) The given mount point is to be selected and the pen drive is to be mounted with the
command: mount /dev/sdb1 /media
(4) Later, the required seven image files are to be copied with the following command:
cp -rf /home/operator/latestimages/*.gif /media
(5) After copying the latest gif images into the pen drive unmount it by issuing the command:
umount /media
32

Step-II.
connected
Copy image files from pen drive into C: drive of windows XP computer
with internet facility.
(1) Pen drive is to be inserted in the above windows computer and the seven gif images
which were copied in pen drive are to be copied/pasted into C: drive directly.
(2) It is to be verified whether the above images have gif extension or not. If they do have gif
extension no furhter action is required else each of the above six files are to be renamed
with file extension changed as gif.
Step-III. Transfering files to ftp server (i.p. address 125.21.185.11) via internet.
(1) Click on START to open start menu and click on “run” command. A new window will be
opened. Now type the command : ftp xxx.xxx.xxx.xxx (xxx.xxx.xxx.xxx is the IP address
of IMD website).
(2) On prompting for user name enter dopler as user id and for password enter dopler2005 as
password.
(3) Change to binary mode by command bin .
1 To transfer multiple files enter command: mput c:\*.gif
2 System will prompt with question whether file
caz_dlh.gif to be sent? y
pac_dlh.gif to be sent? y
ppz_dlh.gif to be sent? y
ppi_dlh.gif to be sent? y
ppv_dlh.gif to be sent? y
sri_dlh.gif to be sent? y
vp2_dlh.gif to be sent? y
On confirming by command y the seven gif images will be transferred. To end the file transfers
enter the command :bye
3.2.Checking radiation of radar
To ascertain that the radar is radiating following procedure needs to be adopted.
At the command prompt issue the following command to view the status, log in as the operator
in the RCP8 computer and issue the command.
scp –rf /usr/iris_data/log/IRIS_ERROR.LOG
internet:/home/operator/Desktop
33

If this IRIS_ERROR.LOG file does not contain any burst pulse missing error message, it can be
concluded that the radar is radiating. By examining the vvp product also it can be concluded
whether the radar is actually radiating. This is an indirect method as it is practically observed that
if radiation is switched off the vvp product will not be showing the velocity barbs. Hence it can
be safely concluded that radar is radiating if barbs are observed in a vvp product.
There is another method, as explained in the Figure 7 to confirm about the presence of
transmitter’s radiation. The “bitex” command is given in a new window of RCP8 after iris is
started and connected to RCP8. A window opens when bitex command is given as shown in the
following photograph. The button on the extreme right is to be clicked to get the details of
transmitter's average RF power output.
Figure 3.1 Checking radiation of radar
Some important software commands used in dwr operation:
3.3. Checking the current directory
[root@DELHI-REMOTE ~]# pwd
3.4. To copy into pen drive
[root@DELHI-REMOTE ~]# cp -rf /home/operator/Desktop/Event /media
3.5. To check weather the given file was copied into pendrive
[root@DELHI-REMOTE ~]# cd /media
[root@DELHI-REMOTE media]# ls
3.6. To delete all files from the directory
[root@DELHI-REMOTE ~]# rm –rf *.*
34

3.7. To search for a file
[operator@DELHI-INTERNET ~]$ su –
(enter the root password)
[root@DELHI-INTERNET ~]# find / -
3.8. Copy of raw data
RAW data is available in the Main & Standby servers in their /usr/iris_data/
product_ raw folder and lda (archive data) folders. This data can be copied to any local server
(or in any other folder which has ample space to store the data) for use with the following
procedures:
Enter the following commands;
[operator@DELHI-INTERNET ~]$ scp –r main:/usr/iris_data/product_raw/DLH
YYMMDD*.* localserver:/usr/iris_data/weekly folder/(or any folder)
Whenever any raw data is missing in main server then it may be available in the standby
server. If missing data is available then it can also be copied from the standby server. The folder
containing the raw data is to be zipped and saved, as the raw data is voluminous.
3.9. Procedure for archiving raw data
It is mandatory that each DWR Station should copy the raw data weekly whenever the
accumulated data reached the size of 4.7 GB. The data is to be compressed by zipping and then
save it in one DVD of 4.7G.B at a time, as the DVD drive provided does not allow multi session.
Normally, one week’s raw data occupies 8 to 9 GB and after compressing to tar.bz2 format, it
occupies around 4GB. Also, monthly data is to be separately zipped and archived in hard disk at
the end of each month for archival of DWR data for future use. 5 years data occupies in 1 TB
hard disk. Detailed information is provided in B.5 of APPENDIX B.
3.10. Procedure for finding the size of a folder
[operator@DELHI-INTERNET ~]$ df -h /usr/iris_data/product_raw/
Filesystem
/dev/sda3
Size Used Avail Use% Mounted on
211G 97G 103G 49% /usr/iris_data
[operator@DELHI-INTERNET ~]$ df -h /home/operator/
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 6.7G 2.8G 3.6G 44% /
[operator@DELHI-INTERNET ~]$ df -h /home/operator/LatestImages/
Filesystem
Size Used Avail Use% Mounted on
35

dev/sda1 6.7G 2.8G 3.6G 44% /
[operator@DELHI-INTERNET ~]$ cd /media
[operator@DELHI-INTERNET media]$ ls
DLH100429202024.RAW71AE KINGSTON
[operator@DELHI-INTERNET media]$ df -h /media
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 6.7G 2.8G 3.6G 44% /
3.11. To check availability of raw data
First, go to the required folder, i.e., LDA or product_raw. Then give the following
commands to know the details of availability and the number of raw data available in the server.
[operator@DELHI-REMOTE]$ cd /usr/iris_data/
[operator@DELHI-REMOTE]$ ls
List of raw data available is displayed. The raw data corresponding to the particular year,
month, date, and time in hours and seconds can be checked. This command can be used to check
the amount of raw data that is being accumulating in the folder.
[operator@DELHI-REMOTE]$ ls -l DLH100101*.* | wc –l
576
The displayed number example 576, indicates the number of raw data files available with
DLH100101. This way the availability of raw data in the folder can be checked.
3.12. How to find out the sweep angles of a given product
The utility productx used to display the details of the product file with the following example:
[operator@DELHI-STANDBY ~]$ productx DLH100819073440.RAWPRTY
------------- Product Summary for DLH100819073440.RAWPRTY -------------
Ingest site name : 'DWRDELHI(PALAM)', Version: 8.12
Ingest hardware name: 'DWRDELHI(PALAM)'
Product site name : 'DLH-STBY-PLM', Version: 8.12
File size: 3735552 bytes (Disk space: 3735552 bytes)
Product type is: Raw Data
36

PCO name: IMD-B, TCO name: IMD-B
PRF: 600/450Hz, Wavelength: 10.62cm, Nyquist: 47.79m/s(V), 15.93m/s(W)
XMT Polarization: Horizontal, Wind:???
Constant:67.42 dB, I0:-113.20 dBm, Cal Noise:-81.99 dBm, Bandwidth:0 kHz.
ZFlags: SP_T, block_zc, attn_zc, target_zc, dpatten_zc, dpatten_z
VFlags: SP_V, 3lag_w, ship_v, unfold_vc, fall_vc, storm_vc
Heights: Radar: 235m, Ground: 216m, Melting: 5400m MSL
Maximum range: 249.8 km
Ingest time: 07:34:40 19 AUG 2010 UTC (0 minutes west) DST:0/0
Volume scan time: 07:34:40 19 AUG 2010 UTC (LT: IST -330 minutes)
Oldest Ing time: 07:34:40 19 AUG 2010 UTC
Product Gen time: 07:41:35 19 AUG 2010 UTC
Input count: 1
Product is not composites.
Full volume scan, Force 8-bit, Selected data recorded
3.13. Script for sending the .gif images to ftp server
#!/bin/sh
# Filename: transmet_gif
# Sends files via ftp, syntax:
# sig_ftp SourcePath DestPath DestHost User Password
trap "" HUP
SourcePath=$1
SourceDir=${SourcePath%/*}
SourceFile=${SourcePath##*/}
DestPath=$2
DestDir=${DestPath%/*}
DestFile=${DestPath##*/}
DestHost=$3
# For security purposes you can always hard code the user name and/or
# password here.
User=$4
Password=$5
# Error checking: Make sure each string has a value.
if [ "${SourceDir}" = "" ]; then exit 1; fi
if [ "${SourceFile}" = "" ]; then exit 1; fi
if [ "${DestDir}" = "" ]; then exit 1; fi
if [ "${DestFile}" = "" ]; then exit 1; fi
if [ "${DestHost}" = "" ]; then exit 1; fi
if [ "${User}" = "" ]; then exit 1; fi
if [ "${Password}" = "" ]; then exit 1; fi
cd $SourceDir
INTYPE=`echo $DestFile|cut -c1-3`
INPPITYPE=`echo $DestFile|cut -c1-5`
37

INHOUR=`echo $DestFile|cut -c24-25`
OUTTYPE=${INTYPE}
if [ "${INPPITYPE}" = "PPI_Z" ]; then OUTTYPE="ppz"; fi
if [ "${INPPITYPE}" = "PPI_V" ]; then OUTTYPE="ppv"; fi
if [ "${INTYPE}" = "MAX" ]; then OUTTYPE="caz"; fi
if [ "${INTYPE}" = "VVP" ]; then OUTTYPE="vp2"; fi
if [ "${INTYPE}" = "SRI" ]; then OUTTYPE="sri"; fi
if [ "${INTYPE}" = "RNN" ]; then OUTTYPE="pac"; fi
if [ "${INTYPE}" = "SHE" ]; then OUTTYPE="3Dshear"; fi
if [ "${INTYPE}" = "VIL" ]; then OUTTYPE="vil"; fi
if [ "${INTYPE}" = "WRN" ]; then OUTTYPE="duststormwarning";
if [ "${INTYPE}" = "RNN" -a "${INHOUR}" != "03" ]; then exit $?;
OUTNAME=${OUTTYPE}"_dlh.gif"
scp $SourceFile "internet:/home/operator/LatestImages/"$OUTNAME
# For debugging, consider adding the -v option, and running
# manually from a shell.
ftp -n -g -v

# Filename: transmet_gif
# Sends files via ftp, syntax:
# sig_ftp SourcePath DestPath DestHost User Password
trap "" HUP
SourcePath=$1
SourceDir=${SourcePath%/*}
SourceFile=${SourcePath##*/}
DestPath=$2
DestDir=${DestPath%/*}
DestFile=${DestPath##*/}
DestHost=$3
# For security, you can always hard code in the username and/or
# password here.
User=$4
Password=$5
# Error checking: Make sure each string has a value.
if [ "${SourceDir}" = "" ]; then exit 1; fi
if [ "${SourceFile}" = "" ]; then exit 1; fi
if [ "${DestDir}" = "" ]; then exit 1; fi
if [ "${DestFile}" = "" ]; then exit 1; fi
if [ "${DestHost}" = "" ]; then exit 1; fi
if [ "${User}" = "" ]; then exit 1; fi
if [ "${Password}" = "" ]; then exit 1; fi
cd $SourceDir
INTYPE=`echo $DestFile|cut -c1-3`
INPPITYPE=`echo $DestFile|cut -c1-5`
INHOUR=`echo $DestFile|cut -c24-25`
OUTTYPE=${INTYPE}
if [ "${INPPITYPE}" = "PPI_Z" ]; then OUTTYPE="ppz"; fi
if [ "${INPPITYPE}" = "PPI_V" ]; then OUTTYPE="ppv"; fi
if [ "${INTYPE}" = "MAX" ]; then OUTTYPE="caz"; fi
if [ "${INTYPE}" = "VVP" ]; then OUTTYPE="vp2"; fi
if [ "${INTYPE}" = "SRI" ]; then OUTTYPE="sri"; fi
if [ "${INTYPE}" = "RNN" ]; then OUTTYPE="pac"; fi
if [ "${INTYPE}" = "SHE" ]; then OUTTYPE="3Dshear"; fi
if [ "${INTYPE}" = "VIL" ]; then OUTTYPE="vil"; fi
if [ "${INTYPE}" = "WRN" ]; then OUTTYPE="duststormwarning";
if [ "${INTYPE}" = "RNN" -a "${INHOUR}" != "03" ]; then exit $?;
OUTNAME=${OUTTYPE}"_dlh.gif"
scp $SourceFile "internet:/home/operator/LatestImages/"$OUTNAME
# For debugging, consider adding the -v option, and running
# manually from a shell.
ftp -n -g -v

3.17. How to copy the products from iris server into pen-drive
Mount the pen drive as per the procedure indicared in 3.1 followed by command:
[root@DELHI-WS ~]# cp -rf /home/operator/Desktop/
3.18. How to copy the error log files from rcp8
After getting connected to RCP8 using ssh command, use the following commands.
[operator@DELHI-RCP8]$ cd /usr/iris_data/log
[operator@DELHI-RCP8]$ ls
Listing of log files is displayed. the following copy command is to be given for getting secured
copy of ERROR files into the Desktop folder of the internet computer.
[operator@DELHI-RCP8]$ scp–r /usr/iris_data/log/IRIS_ERROR.LOG internet:
/home/operator/Desktop
3.19. Responsibilities of station in-charge
1 Overall supervision of DWR station.
2 To ensure discipline, punctuality and performance at station. To optimize output from
staff, efficiently manage the available staff in view of severe shortage of staff faced by the
office. He may devise new schemes, rosters, methodologies, and adaptive roles to be
played by officers of various cadres to manage efficiently the operation and maintenance
of radar. He should ensure that proper log books are maintained at the station.
3 To repair minor problems of radar within 2 hours and to report to radar lab in O/o
DDGM(UI) or any other nodal office assigned by them to be responsible for providing
technical support for WSR-98D/S radars.
4 If the Time Of Restoration (TOR), hereafter called as TOR, is expected to be beyond 2
hours, message is to be displayed in the IMD website that radar is under maintenance.
5 To seek the help of other DWR Stations and H.Q in case of difficulty in radar maintenance
due to severity of the problem or non-availability of spares.
6. To prepare various flow charts at block-diagram level for various signal paths like servo
control, Video Generation, various interlocks, etc., using technical manuals and personal
observation of wiring during maintenance. This greatly enhances the speed of servicing
and also helps a newly posted staff members at the station.
7. To liaise with various forecasting offices to increase the utility of DWR Products.
8. To conduct seminars/workshops in order to enhance the working knowledge of staff at the
station and to impart training to forecasters in understanding DWR Products.
40

9. To liaise with other DWR stations to share the knowledge in radar maintenance and
spares.
10. To find the alternate long-term solutions for recurring technical problems.
3.20. Responsibilities of operator
1. He should know the overall functioning of DWR at block diagram level. He must be able
to explain the role of each and every sub-unit in radar operation.
2. He should make proper and timely entries in the log books.
2. He should be thorough with the procedures to switch ON and switch OFF radar with full
confidence and ease.
3. He should be thorough with the operation of UPS and different connectivity switches like
INPUT/ OUTPUT/ BYPASS/BATTERY INPUTS/ STATUS DISPLAYS etc.
1. He should know the various controls and settings of AC units at the station. He must have
an understating of the principles of the AC in operation at the station and their
maintenance schedules/techniques.
5. Minimum knowledge of standby generator operation, it’s functioning.
6. Thorough knowledge of safety features of RADAR.
7. Thorough knowledge of various communication networks inside and outside radar like
VPN, Broadband, Radar internal communication networks etc.
8. He should have complete information on user names and passwords for the operation and
restoring various radar sub-units, computer systems communications etc.
9. He must be thorough with various products generation in real time and off-line from
achieved data to be supplied to various users in short notice.
10. General supervision of subordinate staff like Chowkidar, Met. Attendants, Safaiwala,
Generator operator s AC operators etc.
11. Generation and dissemination of RADAR products regularly for routine transmission.
12. Briefing visitors on radar technology and products.
13. Generating a brief for use by forecasters based on various radar products during bad
weather, depressions, cyclones, storms etc.
14. To assist senior officers in now-casting by giving inputs as and when required.
41

CHAPTER 4
4.1 General information
DWR MAINTENANCE APPROACH
This chapter provides a brief on system-level orientation to WSR-98D/S maintenance
functions and procedures. For details kindly refer “Maintenance Instructions Radar Data
Acquisition (RDA) (MEHB 10-510): PART-1 and PART-2”. The WSR-98D/S Maintenance
approach entails centrally monitoring systems performance at the RCP8 and IRIS level to
localize the failures through the use of software and hardware maintenance features and to
replace the failed line replaceable unit (LRU) from on-site or depot spares. Diagnostic software
and maintenance features are designed to rapidly detect and isolate malfunctions so that
LRU(Line Replaceable Unit) fault isolation, removal, and replacement can all take place within
one half hour of failure detection with subsystem maximum downtime of less than one hour (2
hours for the RDA). An LRU is defined as a self-contained unit/module/assembly to which a
fault can be isolated and does not require disassembly of the Next Higher Assembly (NHA) other
than disconnecting cables.
4.2 Maintenance
The WSR-98D/S maintenance is based on minimizing system down time in support of the
operational requirement for the radar system. The maintenance approach makes, maximum use
of Built-In-Test Equipment (BITE), on-line status and performance monitoring and off-line
diagnostic programs. Basically in broad way we can divide the maintenance into two types.
1. Preventive Maintenance
2. Corrective Maintenance
The first one is most important and should be followed strictly to avoid any major breakdown of
the radar. It may be noted here, if any minor fault/ problem occurred related with smooth
operation of the system, it should be attended immediately and avoid to linger on it, otherwise
major fault/problem will occur and may cause damages of various part/components or even
modules of the whole system. Both the above types of maintenance are being discussed here in
brief.
4.2.1 Preventive maintenance
Introduction
Preventive maintenance (PM) for the WSR-98D/S consists of scheduled inspections,
replacements and servicing procedures designed to ensure continuous operational availability of
the WSR-98D/S Unit. The inspection and servicing procedures are performed to accomplish one
or more of the following objectives:
42

• Detection of deterioration caused by exposure to the elements (corrosion, sand, dust,
moisture, fungus, salt, etc.)
• Detection of excessive wear of mechanical parts
• Cleaning or replacement of filters and general housekeeping tasks
• Cleaning, replacement or topping-off of essential fluids and greases
• Performing operational checks under test and inspection conditions.
These procedures are contained in the other WSR-98D/S Manuals. The equipment maintenance
manuals also provide specific reference to selected commercial manuals for additional PM
procedures.
Why we need for Preventive maintenance?
- Prevention is better than cure - Needed for system reliability
- Help to correct grey faults - Build familiarity & confidence
The following Table showing periodic preventive maintenance is required for various subsystems
of Radar
Month
Sub-System
Antenna
Servo
Nature of
Préventive
maintenance
& Monthly
Visual Check
Sound Check
3-monthly
Lubricant Check
Slip ring Cleaning
6-monthly
Lubricant Quantity
Leakage Check
Angle setting and
error check
Yearly
Grease Supply
Lubricant Change
Friction Torque
Check Slip ring, Brushes
Check
Limit Switch
Function Check
Servo Voltage,
Frequency Check
1 2 3 4 5 6 7 8 9 10 11 1 2
o o o o o o o o o o o o
o
o o o o
o
o
43

Month
Sub-System
Transmitter
Receiver
\
Nature of
Préventive
maintenance 1 2 3 4 5 6 7 8 9 10 11 1 2
Monthly
Visual Check
Meter Readings
Air Filter Cleaning
6-monthly
Klystron Rotation
Performance Check
Transmitter calibration
Yearly
HV Circuit Cleaning
Interlock Function Check
Voltage
Power
measurements
HV components
visual check
Monthly
Visual Check
6-monthly
Zauto / SP
calibration
Yearly
Gain Check
STALO, COHO
Level Check
Linearity Validation
Dynamic range
check
Noise
Figure
measurement
o o o o o o o o o o o o
o
o
o o o o o o o o o o o o
o
o
o
o
4.2.2 Corrective maintenance
Component Replacement and Setup Procedures
This section provides an overview of the replacement of those WSR-98D/S Line
Replaceable Units (LRUs) which required special handling or set-up procedures. The procedures
are contained in Maintenance Instructions Radar Data Acquisition (RDA) (MEHB 10-510):
PART-1 and PART-2. The great majority of WSR-98D/S LRUs are either standalone, plug-in, or
44

ack-mounted modules which do not require special replacement instructions. Visual inspection
and reference to cabinet layout/interconnection drawings to determine access requirements, cable
connections and fastening hardware suffice for most LRUs. There are three types of LRUs,
however, for which special procedures are required. These include certain electromechanical
assemblies, printed circuit cards, and peripheral communication devices. Each of these types is
defined in the following paragraphs.
4.2.2.1 Electro-mechanical Assemblies: The major electro-mechanical assemblies in the WSR-
98D/S equipment which require special handling instructions are located in the Transmitter
(UD3), and the Antenna Pedestal (UD2). Other LRUs in this category are radome, tower, or
shelter-mounted devices.
4.2.2.2 Printed Circuit Cards: Some of the printed circuit cards in the WSR-98D/S require
removal or installation of jumpers (straps) before they are installed into the WSR-98D/S
equipment. Some cards require the proper setting of miniature built-in switches before they are
installed. These switches are usually Dual-In-line Package (DIP) style switches. The reason for
this requirement is that some of the cards can function in several different modes or
configurations. They must be configured for their specific WSR-98D/S application at the time of
installation. The equipment group maintenance manuals provide Tables for determining the
proper strap/switch setting for each unique card location and include card layout Figures for
positive identification of all straps/switches which require technician action.
4.2.2.3 Peripheral Communication Devices: Most of the communication devices used in the
WSR-98D/S equipment are universal RS-232 and Ethernet devices capable of operating in a
wide variety of applications. Instructions to accomplish the correct setup for the WSR-98D/S
applications are referenced in the applicable setup procedure.
4.3 Bitex utility
Introduction: The bitex utility provides a maintenance facility at the primary level through
graphical user interface for the display of status information of associated sub-systems reported
by Built-In Test Equipment (BITE) integrated into the radar. Hence, at the primary level,
servicing can be started through software commands and the problem can be explicitly
understood as to its location and this awareness creates a confidence that the problem can be
solved in such and such period of time depending on the availability of spares.
Bitex also allows for operator’s initiated commands to be sent to these BITE units (through
the RCP8). These features are very useful in that through the graphical user interface of bitex, an
operator can cause physical functions to take place at the remote radar (i.e. reset faults, start
equipment, switch power systems, etc). Also, electronic button pushes can be decoded by the
RCP8 into control variables which can be further utilized by the RCP8 in logic equations to
make complex functions to take place.
4.3.1 BITEX configuration
Bitex can handle as many as 256 pieces of data from up to 16 separate BITE units. For
example, the antenna sub-assembly many be one BITE unit, the transmitter a 2 nd , the radar
45

controller a 3 rd etc. But, our RCP8 is customized to display 13 BITE units, which can be seen in
the screen shot1.
Screenshot 1 : Opening BITEX window
All BITE units are connected electrically to the Radar Control Processor (RCP) via
interfaces such as contact closures, analog voltages, or serial communications. For maintenance
purposes time variations of these units can be customized for display in graphical user interface.
The RCP8 integrates all of this information and sends it via multicast networking to IRIS for
ultimate display in the bitex utility. These packets are mingled with the RCP8 antenna controller
commands on the same network port.
Invoking Bitex: Bitex is invoked graphically either from irisnet, utils or from the Radar Status
Menu. However, bitex can also be invoked from the command line with the following command:
$bitex&
4.3.2 BITEX Units and their parameters
All the BITE units are shown in 13 sub-panels and parameters contained by each unit are
given below in detail for clarity. Each parameter is an active button.
(1) Calibration Control: This control contains the status of 4-Position switches of Klystron,
Tx RF, continuous wave, noise source and status of COHO modulation and receiver protector.
All these units from 1 to 4 can be seen in the four panels of screenshot 2.
46

Screenshot 2 : Calibration Control & Results, Operator Control & RF Gen. status
(2) Calibration Results: This unit contains the parameters: zcal, zcal delta, dynamic range,
pulse width, noise Figure, velocity measured and velocity delta, results of the calibration done on
any earlier date.
(3) Operator Controls: Controls setup earlier in the case of antenna waveguide command
and audible alarm can be seen in this display. This unit contains the parameters: status of audible
alarm enable, audible alarm1 and 2, antenna waveguide command and doublet.
(4) RF Generator Status: This unit contains the parameters: Status of receiver protector and
four fail signals.
(5) DCU AZ Status : This unit contains the parameters: Status of all units of AZ Servo, AZ
encoder LED, gearbox oil level, bull gear oil level, AZ hand wheel engage, AZ motor over
temperature, Az STOW pin engage, AZ Servo amplifier power supply are seen in the display.
These units from 5 and 6 can be seen in the panels of Screenshot 3.
47

Screenshot 3 : DCU AZ & EL Status
(6) DCU EL Status : This unit contains the parameters: Status of EL dead limit, EL +/- limit,
El encoder light, EL gearbox oil level, EL servo AMP inhibit, short and over temperature, El
motor over temperature. Whether EL stow pin and hand wheel are engaged, EL servo power
supply is, on or not, can be seen in the display.
(7) DCU General Status: This unit contains the parameters: 150V over voltage, 150V under
voltage, Pedestal interlock. The units 7 and 8 can be seen in the sub-panels of Screenshot 4.
(8) DCU Self Test Status: El and AZ Commands, corresponding BITS, El and AZ Servo
speeds (These were not configured)
Screenshot 4: DCU General & Self test Status
(9) DAU Bytes 0-3 : This unit contains the parameters: Filament Power Supply, Klystron
Preheat, Transmit not avail, Waveguide/PFN Interlock, System Control Mode, Maintenance
Work Status, PFN Pulse Length, Spect Filter Low Pressure, Waveguide Arc, VSWR Fault,
48

Antenna Waveguide Switch, Circulator Temperature, Cabinet Interlock, Cabinet Air
Temperature, Cabinet Air Flow, Tx +/-15VDC, Tx 5VDC, Tx 28VDC, Tx 45VDC, Filament
Power Supply Voltage, Vacuum Pump Power Supply Voltage, Focus Coil Power Supply
Voltage, Mod overload, Mod Inver current, Mod Switch Failure, Main Power High Voltage,
Flyback Charge, Inverse Diode, Trigger Amp. These units 9 to 10 can be seen in the sub-panels
of Screenshot 5.
Screenshot 5 : DAU Bytes 0-3 and 4-7
(10) DAU Bytes 4-7 : This unit contains the parameters: Tx Over Voltage, Tx Over Current,
Focus Coil Current, Focus Coil Air Flow, Tx Oil Temperature, PRF Limit Summary, Tx Oil
Level, Tx Summary, ‘one’ test bits 0-7, Klystron Over Current, Klystron Over Current,
Klystron Filament Current, Klystron Vacuum Current, Klystron Air Temperature, Klystron
Air Flow, Mod Switch Maintenance, Post Charge Regulator Maintenance, Waveguide
Pressure/Humidity.
(11) DAU Bytes 8-11: This unit contains the parameters: HV on/off, DAU UART, DAU
Communication. These units 11 and 12 are shown in sub-panel of Screenshot 6.
Screenshot 6: DAU Bytes 8-11 and 12-13
(12) DAU Bytes 12-13: This unit contains the parameter: Radom Access Hatch open/closed.
49

(13) DAU Analog Status: This unit contains the parameters: Shelter Temperature, Tx Exhaust
Temperature, Radome Temperature, Tx RF Avg. Power, Antenna Avg. Power, DAU Test0,
DAU Test1, DAU Test2, Pedestal 15V PS, Pedestal 5V PS, Pedestal -15V PS, DAU 15V PS,
DAU 5V PS, DAU 28V PS, DAU -15V PS. This unit can be seen in Screenshot 7.
Screenshot 7: DAU Analog Status
Screenshot 8: Histogram of Tx RF Avg Power
All the BITE units and corresponding parameters are active buttons. On right-clicking any
of these buttons in the sub-panels, its corresponding histogram (as shown in the above
screenshot 8) is displayed, as a time series for ten minutes duration till that particular minute, in a
new window. The graphical display can be a valuable tool when assessing the frequency and
endurance of faults. The time scale for viewing the histogram is adjustable from 10 minutes to 96
hours using the Time Span slider. The y-axis scale for analog output is also adjustable with the
Vertical Span slider. Each circle represents the time a status packet was received. The graphical
display may be printed to a printer or file. A new log file is generated each day at midnight and
saved in a file. An IRIS setup question allows the operator to choose how many days of antenna
log files to retain at any given time. Keeping old log files preserved is helpful for post analysis of
problems.
50

4.3.3 Bitex data point configuration
Bitex supports 3 types of data points (or unit). There are status data points (information
received from the RCP), status QBITE point (from the RCP), and control data points
(information sent to the RCP). Graphically, the status data point looks like the following:
Graphically, the control data point looks like the following:
Graphically, the status QBITE data point looks like the following:
Status points are passive (accept no user input). They graphically display status
information as reported by the RCP control data points are active. They provide the operator with
a button that can be pressed or toggled. The status of the button is sent to the RCP. The RCP
decodes this and uses this state to affect electrical outputs.
Control data point (here control fault generation) can be set to either “None,” “Low,” or
“High.” “None” means not to generate a fault based on this bit; otherwise the warning flag
indicates the level considered a fault. If a fault is possible, the fault can be further conditioned
with the Disable Warning field. If the warning flag is set (value other than none), then if the data
point is in the unfaulted state, it the LED indicator will be displayed as green. If the data point is
in the faulted state, the data point will be displayed as either yellow (non–critical), or red
(critical) depending on the state of the Critical button (next to the Warning Flag selection).
For example, in a practical case, radar breakdown occurred due to a cable cut in the path
from receiver protector driver module to receiver protector. When bitex was opened, rf status,
DAU 0-3, DCU general are displaying red and DAU 4-7 is displaying yellow, as shown in the
following photo.
51

Figure 4.1. Bitex main panel when fault came
At the time when servicing started, the reason why these were displaying red and yellow
were not known. So, the trouble–shooting was done in a systematic way as follows:
(1) Zauto was opened and checked autocal. The calibration was ok.
(2) Antenna and ascope were opened.
(3) DCU general is displaying red and so, on right-clicking it, RF generator status is displayed
with fault at receiver protect.
(4) Then all the orange cable wiring and cable to receiver protector (J4) was checked. It was
found ok.
(5) Later, connected to rvp8 by ssh command and rebooted the rvp8.
(6) As DAU bytes 0-3 was red, it was opened, and it was showing fault in Klystron preheat.
Hence, it was concluded that preheat was not available due to receiver protect signal not
available. So, it was concluded that the cables connecting to receiver protector should be
checked physically.
(7) Hence, all cables connected to receiver protector were checked with CRO and also
physically. It was finally found that one cable no.4 connecting to receiver protector was
found cut and it was soldered. Radar was turned on and then preheat became available.
(8) Then HV was switched on and then radar started working ok.
52

APPENDIX A
AN OVERVIEW OF DOPPLER WEATHER RADARS
A.1. DOPPLER WEATHER RADAR SYSTEM OVERVIEW
Doppler Weather Radars are used to detect, process, distribute and display meteorological data
OVER a large area. Doppler technology opened new trends in the field of the radar meteorology
and increased the performance of weather radars significantly. Doppler weather radars are
capable of acquiring particle velocity data in addition to echo range, direction, and reflectivity
data. Software processing is used to control the radar operating characteristics to produce the
optimum radar volume coverage patterns and to optimize the radar returns. The base weather
data is then processed through the application of meteorological algorithms to generate base and
derived weather products. These products are further processed using graphics algorithms to
produce interpretable weather data displays on color monitors in the form of images. After
receipt of the reflected echo from target, the signal passes from processing stages for product
generation. These stages include many complex processes and algorithms carried out by various
weather radar software. This SOP is prepared to operate Weather Radar network of India
Meteorological Department with the uniform operations for better understanding and to create
mosaic-ing for whole DWRs network, under IMD Radar Network around the country. The
existing Cyclone Detection Radar Network in IMD shown in following Fig. A.1 and Storm
Detection & Multi-met Radar network is shown in Fig. A.2
Figure A.1 Cyclone Detection Radar Network
Network
Figure A.2 Strom Detection and Multimet Radar
Doppler Weather Radars employs high dynamic-range linear receiver and DSPs (digital signal
processors) to extract information from the received echo power. Linear receiver output in
intermediate frequency (IF) and analog form is converted to digital form in the analog-to-digital
53

converter and fed to digital filters to split the power into two channels i.e., for (i) in-phase (I) and
(ii) quadrature phase(Q) components. Digital Signal Processor (DSP) chips process the raw I and
Q data and perform phase and amplitude correction, clutter filtering, covariance computation and
produce normalized results. These normalized results are tagged with angle information, headers
and given out as a data set. Covariance computation is based on pulse pair processing. Intensity
estimation consists simply of integrating the power in the linear channel (I* 2 + Q* 2 ) over range
and azimuth. The resulting power estimate is corrected for system noise, atmospheric attenuation
and transmitter power variations. The signal processing of the linear channel ends with the
estimation of reflectivity, mean radial velocity and velocity spectrum width.
Figure A.3. General signal flow chart of radar system
Figure A.4. Basic block diagram of radar
54

A.1.1. Future IMD Radar Network plan under modernization
Under IMD modernization, in Phase-I, IMD has procured 12 numbers of S-Band Doppler
Weather Radars (WSR-98D/S) from M/s Metstar Beijing CHINA. Out of these 12 DWRs
presently three DWRs have already been installed and functioning at IGI Airport Palam, New
Delhi, M. C. Hyderabad and M. C. Nagpur and installation for remaining nine DWRs at M. C.
Agartala, Mohanbari, M. C. Patna, M. C. Lucknow, M. O. Patiala, M. C. Bhopal, CDR
Paradeep,, CDR Karaikal, R. M. C. Mumbai, CDR Goa and at CDR Bhuj, besides the above
mentioned DWRs installation IMD is going to Installed two more C-band imported DWRs at M.
C. Jaipur and IMD HQ Mausam Bhawan New Delhi in near future and installation and
commissioning of two indigenous S-band DWRs are also in progress. Further under
modernization phase-II, IMD will be installed 34 or 35 more S-band and C-band radars to
enhance weather radar network for better coverage of all the areas of the country and to improve
weather now-casting and forecasting. .
A.2.A. brief introduction of WSR-98D/S Doppler Weather Radar
The basic WSR-98D/S system mainly consisting following four equipment groups, which are
interconnected to provide the WSR-98D/S operational requirements.
► RDA Group
► RVP8 Group
► RCP8 Group
► IRIS Group
A.2.1. Radar Data Acquisition (RDA) Group. The RDA comprises the Doppler radar and
provides base weather data. The RDA is the Doppler radar subsystem which generates and
radiates RF pulses, then acquires and processes reflected RF signals to obtain base data. The base
data consists of measurements of reflectivity, mean radial velocity, and velocity spectrum width.
Base data is available in digital format for archiving and for onward transmission to the RPG
Group i.e., RVP8 Group. The RDA is a self-contained unit designed for continuous, unattended
operation. The RDA includes the Radar Transmitter, Antenna/Pedestal, Radar Receiver, and
Data Processor Cabinet.
A.2.2. RVP8 Group. The RVP8 Group consists of the RVP8 Digital receiver/signal processor,
which is implemented using an open hardware and software architecture on standard PC
hardware under the Linux operating system as compared to previous processors those were
mainly built on proprietary DSP chips basis, the most innovative aspect of the RVP8 is that it is
implemented on standard PC hardware and software that can be purchased from a wide variety
of sources. The Intel Pentium/PCI approach promises continued improvement in processor
speed, bus bandwidth and the availability of low-cost compatible hardware and peripherals. The
performance of an entry level RVP8 (currently dual 2.4 GHz Pentium processors) is 6 times
faster than the earlier one RVP7 ever produced (with two RVP7/AUX boards).
Besides the open hardware approach, the RVP8 has an open software approach also. The RVP8
runs in the context of the Linux operating system. The code is structured and public API’s are
55

provided so that research customers can modify/replace existing SIGMET algorithms, or write
their own software from scratch using the RVP8 software structure as a foundation on which to
build.
The advantage of the open hardware and software PCI approach is reduced cost and the ability
for customers to maintain, upgrade and expand the processor in the future by purchasing
standard, low cost PC components from local sources.
A.2.3. RCP8 Group. The RCP8 Group provides position and velocity servo control for both the
AZ and the EL axes of the antenna, the status monitoring of the Transmitter /Receiver/Antenna
servo systems and the control functions such as Radiate On/Off and Servo On/Off. An Ethernet
interface can be connected virtually to any workstation or PC and is fully compatible with
SIGMET’s RVP8 signal processor and IRIS software system.
A.2.4. IRIS Group. The IRIS Group is a set of advanced software products for use with either
Doppler or non-Doppler weather radar applications. IRIS was developed by SIGMET, Inc., to
provide virtually all of the features required for the operation of a radar network and distribution
of radar products, including:
• Local and remote radar control.
• Real time display for the local or networked workstations.
• PPI, RHI and interactive, manual scanning.
• Advanced radar signal processing and control features for data acquisition.
• Advanced radar product generation — CAPPI, PPI, RHI, vertically integrated, liquid, echo
tops, cross section, maximum reflectivity, wind shear, and rainfall accumulation with
full interpolation in polar coordinates.
• Generation of automatic warnings for sever weather events like Dust Storm, Thunder
Storm, Hail and Microburst etc.
• Forecaster features like loop, geographic cursor, storm tracking and forecasting, and
interactive cross section modes.
• Archiving and playback of products and raw data.
• Comprehensive alignment and calibration.
• Comprehensive diagnostic and system monitoring.
• Product generation from both real time and archived data.
IRIS Group has main three following configurations of the IRIS system are used in the WSR-
98D
IRIS/Radar Installed at the radar site on the RCP8 computer, the IRIS/Radar system runs the
radar and signal processing hardware and generates ingest files (input data) and raw data for
other IRIS sites. It can support either the basic or the full product set.
IRIS/Analysis Installed at a central office, the IRIS/Analysis system receives raw data products
from the radar site over the network or from an archive device, such as a tape or disk. It supports
the full product set. Remote control and monitoring are also supported.
56

IRIS/Display Installed at remote workstations, the IRIS/Display system receives processed
product files or raw data over the network or from an archive, and uses them for display
purposes. It supports the basic product set. Remote control and monitoring are also supported.
A.3. Base Products received from Doppler Weather Radars
A.3.1. Reflectivity factor (Z)
This is the integral over the backscatter cross-section of the particles in a pulse volume. As per
the empirical relation, the reflectivity for the particles those are small as compared to the
wavelength the scatter cross-section will be D6, where D is the diameter of the particle. Radars
are calibrated in the way to give directly (assuming the dielectric constant of water) the
reflectivity factor from the received backscattered energy. The units for the reflectivity factor are
mm6 m-3 or in the logarithmic value it is denoted in dBZ, as indicated in the color scale in
following Figure A.5
Figure A.5. Reflectivity factor (Z)
A.3.2. Doppler velocity (V)
Doppler velocity is reflectivity-weighted average velocity of targets in the pulse volume and
determined by phase measurements from a large number of successive pulses. This is also called
radial velocity and gives only the radial component of the velocity vector. It is generally assumed
that raindrops and other particles are advected with the wind and have no own motion except
their falling velocity. A PPI picture of radial velocity is shown below in Figure A.6.
57

Figure A.6. Doppler velocity (V)
Figure A.7. Spectral width
A.3.3. Spectral width (W)
Spectral measure is a measure of the dispersion of velocities within the pulse volume and
standard deviation of the velocity spectrum. Spectral width depends among others from the
turbulence within the pulse volume. As shown in Figure A.7.
58

APPENDIX B
WSR 98D/S DWR SYSTEM CHARACTERISTICS AND CAPABILITIES
B.1. WSR 98D/S SYSTEM CHARACTERISTICS
B.1.1. General
a. Frequency range - 2700-2900 MHz.
b. Peak power- Higher than 500 KW at the antenna feed.
c. Pulse width
Low PRF mode- 2 µ sec.
Velocity mode- 1 µ sec.
d. Primary Power requirement.- 230V/25 Amp. in each phase & phase to phase 440 V, 3
Phases, 50 Hz.
B.1.2. Transmitter
a. Power device- Klystron.
b. Tunability - Manually tunable over the range of 2700-2900 MHz.
c. Spectral purity- RMS phase error, pulse jitter consistent with desired accuracy.
d. Pulse Repetition- 250 to 1200 PPS, variable, computer controlled Pulse Repetition
Frequency (PRF) consistent with requirements.
e. T.R. Switching- Ferrite duplexer with 5 µ sec or less recovery time; total isolation of 60
dBm minimum.
f. Sector blanking- Transmission should be automatically switched off between any two
selectable angle intervals in Azimuth & Elevation respectively.
B.1.3. Receiver
a. Frequency range- 2700-2900 MHz.
b. System noise Figure Better than 2 dB and consistent with the measurement accuracy
requirements.
c. Type of Receiver- -Fully coherent digital receive Linear channel shall have dynamic range
of 95 dB or better and dynamic range sufficient to ensure required sensitivity and prevent
saturation for all the meteorological phenomena within operating range.
59

B.1.4. Antenna system
a. Type - Feed Horn mounted on parabolic solid surface reflector.
b. Diameter - 8.6 meters i.e., 28 feet (nominal).
c. Beam Width- 0.95 degree pencil beam at 2800 MHz measured at 3 dB points.
d. Polarization- Linear Horizontal.
e. Side lobes 28 dB or better down from the main lobe to 12 degrees, 30 dB or lower
thereafter.
f. VSWR (Voltage Standing Wave Ratio) 1.15 : 1 maximum (with radome).
g. Safety Switch provided on antenna pedestal and at servo amplifier assembly.
h. Wave guide - Material – Aluminum.
The entire R. F plumbing shall be capable of operating satisfactorily at the prevailing
environmental conditions.
i. Type of pedestal -Elevation over azimuth.
B.1.5. Antenna scan details
B.1.5.1. Azimuth movements
a. Automatic mode 360 degrees continuous.
b. Manual mode -- Manually settable to any azimuth angle.
c. Azimuth rate Variable from 0 to 6 RPM.
d. Azimuth Accuracy 0.2 degrees or better.
e. Azimuth Resolution 0.1 degrees.
B.1.5.2. Elevation movement
a. Automatic mode - 1 degree to + 70 degrees.
b. Manual mode - 1 degree to +92 degrees.
c. Elevation speed in automatic mode Variable up to 5 scans per minute.
d. Elevation Speed in Manual mode Variable from 1 to 6 degrees per second.
60

e. Elevation limits -- Upper and lower limit-switches for elevation limit protection with hard
stops.
f. Elevation Accuracy - 0.2 degrees or better.
g. Elevation resolution - 0.1 degrees.
1.5.3. Scan Modes
1.5.3.1. PPI Mode
a. Continuous : Continuous azimuth rotation at any Selectable elevation angle.
b. Sector : Sector scan with selectable width and centre angle.
c. Volume : Volume scan at selected elevation steps.
1.5.3.2. RHI Mode
a. Automatic : Automatic RHI Scanning at selected azimuth angle.
b. Manual : Manual control of any azimuth and elevation angle at selected elevation PPI
Scan and at selected azimuth RHI Scan.
B.1.6 Radome
a. Type Foam sandwich rigid spherical curved panel.
b. Color White
c. Size Compatible with the dish supplied. Shall have adequate space for
maintenance personnel to enter and work conveniently.
d. Wind load Average 200 km /hr and gusty 300 km/hr
e. Transmission loss less than 0.15 dB (one way)
f. Lightening Protection Lightning rod with dual ground wires
g. Obstruction lights Twin Light System with solar powered auto switch
h. Entry one door and entry from bottom
i. Ventilation Three ventilators protected from entry of rain water, Insects and
rodents.
j. Ladder Approachable to Obstruction lights.
61

B.1.7. Displays
All displays are flicker free, memory backed, fast refresh type for viewing in normal ambient
light and
having the following features:
(i)
(ii)
(iii)
Provision of electronic cursor synchronizing with antenna position for PPI/RHI
presentation in real time display monitor.
Provision of soft overlay in GIS format with 1 km resolution with user selectable colors
for coastline, State/ district boundary, rivers, town/ city names and latitude/ longitude grids
in all displays.
Provision of markers for range and height with user selectable values.
1.7.1. General features
a. Size 29” - 1 No
36’ × 24’ Plasma - 1 No
53cm (21’’) or larger - 5 Nos.
b. Type super VGA LCD color monitor
c. Display resolution 1600 × 1280 or better
d. Color levels selectable from palettes of minimum 256 colors
B.1.8. RVP8, the best and latest Radar Signal Processor
a. Processor type: based on pulse pair algorithm.
b. Averaging: compatible with accuracy and scan rate requirements and optionally selectable
from 4 to 256 pulses as per operational requirement.
c. Clutter rejection : compatible with clutter rejection requirements of the system as per
accuracy limits, standard IIR (Infinite Impulse Response) filtering (minimum 5 poles)
with 30 dB and 50 dB (nominal values) rejection and selectable width with facilities
for site optimization.
d. Output: 12 bit.
e. Design: Provision shall exist for user programming with easy to use assembly language
and standard C & C++ language.
f. Data quality: The processor to have thresholds values on clutter and signal quality index
etc to discard questionable data.
62

B.1.9. Calibrations and health monitoring
1.9.1. Internal calibration
The system shall perform automatic internal calibration at least once every volume scan cycle
and display the current values.
Parameters are being calibrated -Linear receiver calibration
-phase calibration
-transmitter peak power
-system noise Figure
1.9.2. External Calibration
Provision is also been made for absolute external calibration using standard coherent source.
1.9.3. Sun Calibration and Pseudo tracking of Sun is provided
1.9.4. Management / Monitoring Utilities.
The system is having at least the following management / monitoring utilities:
1. Power up device for quick GO/ NO GO decision
2. Full- fledged diagnostics for radar signal processor.
3. Utility for system installation and configuration
4. Utilities to assist in overlay generation
5. Trigger timing calibration utility.
6. Utility for alignment of color displays.
B.1.10. Built In Test Equipment (BITE) Processor
1.10.1. A modern system making use of latest technology for continuous monitoring of the
operational status of functions and utilities of the radar system are incorporated in the said
system.
1.10.2. BITE Processor is measure and process a number of real time analog and digital
parameters in the radar system and accordingly generate and display an error message whenever
their value falls up/down then specified permissible range. BITE processor is continuously
monitoring input and output signals of every module/PCB for any deviation from the standard
value. Whenever any error message is generated, BITE Processor will also indicate failure of the
equipment, at the level of PCB and sub-module level. The BITE information will be available
online on any workstation as well as on radar system monitoring unit.
63

1.10.3. BITE Processor will cause the malfunctioning units to be switched off automatically. An
acoustical alarm will also be generated for warning the operator.
B.2. Capabilities of Doppler weather radars
The Duty Asstt. /Radar Operator (the one who is) operating the Doppler Weather Radar must
have the knowledge of following general information about capabilities of Doppler Weather
Radar systems. The state of art WSR-98D/S, S-band Pulsed Doppler Weather Radar systems
have the following capabilities:
B.2.1. Modes of operation
The system has capabilities of operation in computer controlled mode for round the clock
observations and archive of raw data and radar images in GIF format:
B.2.2. Parameters to be measured
a. Reflectivity
b. Radial velocity (radial velocity).
c. Spectrum Width
B.2.3. Observation range
a. Reflectivity- 500 km
b. Velocity- 250 km
B.2.4. Spatial resolutions
a. Reflectivity- 300m or better
b. Velocity- 150m or better
B.2.5. Measurement accuracy
a. Reflectivity - Minimum 2 dB absolute accuracy at 250 km for rainfall equivalent to 23
dBZ (1 mm/hr) at antenna rotation of 2 revolutions per minute (RPM)
b. Velocity - Minimum 1 m/sec at 250 km for rainfall equivalent to 23 dBZ reflectivity at
antenna rotation of 2 RPM.
c. Spectrum Width - Minimum 1 m/sec at 250 km for rainfall equivalent to 23 dBZ
reflectivity at antenna rotation of 2 RPM.
64

B.2.6. Unambiguous range
a. Reflectivity mode - 500 km or better.
b. Doppler mode - 125 km (subject to Para 2.6.1 b)
B.2.6.1. Ambiguity resolution
a. In the Doppler mode, the System has facility for unfolding velocities four times the
nyquist velocity to overcome the restriction imposed by range-velocity dilemma (Doppler
dilemma). The algorithm proposed and used is having capability of unfolding velocities in
cases of non-overlaid echoes as well as for overlaid echoes.
b. Ambiguity resolution techniques for automatic generation of unambiguous velocity at least
up to ±60 m/sec at 250 km range and 2 RPM scan rate is provided.
B.2.7. Product generation
The DWR system is capable of generating the following types of products:
a. Base products
b. Primary products
c. Derived products
The System has provision for display and archival of the products also.
B.2.7.1. Product range:
i. Reflectivity - 0 - 500 km or better
ii.
iii.
Velocity - 0 - 250 km or better
Spectrum Width - 0 - 250 km or better
B.2.8. Operating environmental conditions
For optimum operation of Doppler weather radars, the following Environmental conditions
should be maintained for 24 × 7 operational.
The system must have the capabilities of operation in a tropical coastal environment under
following environmental conditions specified below:
1. For DWR Antenna, Pedestal and Radome:
a. Temperature 0 to 55° C
65

. Relative Humidity up to 100%
2. For DWR Transmitter, Receiver and Servo unit :
a. Temperature 0 to 50° C
b. Relative humidity up to 90%
3. For all Computer systems:
a. Temperature 25 C ± 10° C
b. Relative humidity up to 90%
B.2.9. MODES OF OPERATION
The system has the following operational capabilities:
1. In Auto Mode Operation:
a. Fully computer controlled operation with selectable scan strategies by user defined and
other variable parameters settable by operator through standard user interfaces of Main
workstation.
b. Operator console interaction for control of radar parameters and display parameters and
selection of products.
c. Provision for Scheduling and Command Sequence Execution.
2. Manual Mode/Maintenance Modes
The System has the following capabilities:
a. Manual operation using the maintenance workstation, independent of the Main workstation
and moving antenna at a single scan level for PPI and at a selectable azimuth for RHI.
b. Antenna position, reflectivity and velocity data shall be displayed on an independent color
monitor in a format stimulating conventional PPI / RHI.
B.3. Product generation control and display capabilities
Product Generation Capabilities
66

The System is capable of generating the following products from the initial raw data output of
the radar processor.
B.3.1. Base Products
B.3.1.1. The system is capable of generating PPI, RHI of base data obtained from the radar
processed after applying different corrections to the data (e.g. beam blockage, incomplete beam
filling, attenuation effects, earth curvature, range normalized etc.)
B.3.1.2. Products are generated online based on PDF parameters of the products already selected
and stored in workstation against the various scan schedule programmed.
B.3.1.3. Provision is also there to generate products offline using the archived raw data.
B.3.2. Primary Products
B.3.2.1. Maximum Display
The System computes maximum values of base data elements (Z, V, σ) in horizontal (East west)
and vertical columns (North South) between user defined heights and displays the partial images
in a single frame.
B.3.2.2. CAPPI (Constant Altitude Plan Position Indicator)
The System is interpolate each primary data from the volume scan data set for a horizontal plane
at user vertical height and display same for user selectable data form Z, V and σ.
B.3.2.3. PCAPPI (PSEUDO CAPPI)
The system is incorporating data form the highest elevation scan near the radar and from lowest
elevation scan for areas at far away from the radar for which radar beams are not intersected by
user defined plane for CAPPI and display same pertaining to data selected by user.
B.3.2.4. VCUT (Vertical Cut)
The system is interpolating all the basic parameters (Z, V, σ) in any vertical plane passing
through user defined two points and display the same for the user selectable parameters.
B.3.2.5. EBASE (ECHO BASE)
From the volume scan data, the system is identifying the minimum height up to which the user
defined threshold value for each base data exists and displays them for user selectable data.
B.3.2.6. ETOP (ECHO TOP)
From the volume scan data, the system shall identify the maximum height up to which the user
defined threshold value for each base data exists and display them for user selectable data.
67

B.3.3. Velocity products
The system generates and display following velocity products:
i. Radial velocity versus the azimuth for a fixed elevation and a fixed slant range (VAD).
ii.
iii.
iv.
Radial velocity at a fixed user defined range on height and azimuth angles (Radial velocity
display for fixed range, azimuth angles for various height and azimuth.
Horizontal wind velocity and wind direction using barbs in a vertical column above the
radar site for different heights including divergence & convergence product.
Horizontal wind vectors (UWT) using barbs at user defined layer height with or without
underlay of reflectivity or velocity in PPI / CAPPI format.
B.3.4. Hydrological products
The DWR system generates and display following hydrological products:
i. Rainfall intensity using Z-R relationship in a user selectable surface layer with constant
height above ground Instantaneous estimation of Vertically Integrated Liquid water
content (VIL) residing in a user defined atmosphere layer in the atmosphere to be
displayed in PPI type of display.
ii.
iii.
iv.
Rainfall intensity histogram at selectable locations within radar coverage during a user
defined time period (this facility is not configured in the M/s Metstar DWRs).
Precipitation accumulation (PAC) in a user definable time period.
Rainfall amount in user defined basins for user defined time span (this facility is not
configured in the M/s Metstar DWRs).
v. Rainfall amount for any user defined period in the past (past number of hours) prior to
product generation.
B.3.5. Aviation products
i. The system has evaluate derivatives of wind velocity in radial, azimuth, elevation, North
South, East West directions and derive horizontal, vertical and three dimensional shears.
ii.
iii.
The system is also able to generate warning product on microburst.
The system is evaluate maximum turbulence within user defined atmospheric layer and
display in top view.
B.3.6. Warning and forecasting products for tropical regions
68

1. System generates hail, thunderstorm and dust storm warning symbols at the places likely to
get affected by hailstorm, thunderstorm, and dust storm using reliable warning
algorithms.
2. System is having capabilities of evaluating speed and direction of movement of weather
systems (track forecasting products).
3. System is also having capabilities of warning, if any, of the conditions defined by the user
are reached or fulfilled on reflectivity, velocity, VIL and wind shear.
4. System is having ability to detect tornado and gust fronts associated with storms and issue
visual and text warning message.
5. The system is able to generate a storm relative velocity product e.g. PPI, PCAPPI removing
the bias of storm motion velocity.
6. The system is capable of providing interactive method for locating storm centre,
superimposing 5°, 10° or 15° soft spiral overlay as per operator’s choice over the
reflectivity image containing spiral bands of the storm. The system is also able to measure
the radius of maximum wind within user defined grid of 5 – 60 km around the storm centre.
B.3.7. Alphanumeric products
The system is also be able to provide data on Reflectivity (Z), Radial velocity (V) and Horizontal
wind velocity, Rain rate in terms of latitude and longitude and heights at user defined height grid
point up to 200 km from radar site in tabular form for ingesting these data into numerical models
for weather predictions, however this facility does not configured in the M/s Metstar DWRs.
B.4. Workstations and display capabilities of the system
B.4.1. Workstations
The WSR98-D/S system is having seven nos. of workstations, as detailed giving below to
perform various tasks of data acquisition, product generation, archival, display and house
keeping. Workstation is based on same hardware platform.
i. Two workstations with identical features having 21″ LCD color monitor (one main and the
other as hot standby) for control and operations involved in data acquisition, product
generation, product display and archival.
ii.
iii.
iv.
One workstation with 21″ LCD color monitor for maintenance, calibration and house
keeping tasks.
One workstation with 29″ LCD color monitor for simultaneous real time display of Z, V, σ
and BITE parameters
One workstation with 21″ LCD color monitor for collecting products, networking and
dissemination of products over internet.
69

v. One workstation with 21″ LCD color monitor for remote display and monitoring of
system performance.
vi.
One workstation with 36″ × 24″ plasma monitor for display and demonstration of various
products with provision of user selectable six display windows at a time .
B.4.2. Display capabilities of the system
2.1. The system is able to display for full radar field up to the maximum range or short ranges
as selected by the operator.
2.2. The system is also provided with facilities for sector display and freedom to locate the
origin of display field corresponding to the radar location at any point on the active part of
the display.
2.3. The system is capable of displaying in real time all or any of the three parameters (Z, V, σ)
in synchronized mode.
2.4. The system is also capable of displaying products generated from archived data in the play
back mode.
2.5. Suitable controls for freeze and animation using time lapse display are also provided.
2.6. System is having facilities for color coding of reflectivity, velocity, and spectrum width
fields up to 32 users selectable levels with user selectable color Tables are provided.
Preset default options of 2, 4,8,16 and 32 levels are available.
B.5. Radar data archival capability
1. Data storage capacity
RADAR DATA ARCHIVAL
1.1. The base data (output of radar processor) is being stored automatically on hard disk in
compressed form 120 GB data or more shall be available on the disc at a time.
1.2. Selective transfer of compressed data from on-line storage (hard disc) to off-line storage
(cartridge / optical disc juke box / magnetic tape) and vice versa is provided. The transfer
will not require more than 10 minute for 1 GB data.
1.3. Plain paper high-resolution color laser printer and color inkjet printer (size A4) for taking
hard copies of images and products shall be provided. The hard copy will generate with in
one minute.
1.4. Laser black and white printer (size A4) for system and data management is provided.
70

1.5. There is provision of DVD Writer in all workstations.
2. Data format
2.1. System is capable of archiving and transferring I and Q data in any universal binary and
ASCII format.
2.2. System is capable of archiving and transferring raw data (base data i.e. reflectivity,
velocity and spectrum width) in universal format like HDF5 / NETCDF / ASCII and
LEVEL-II format.
2.3. System is capable of generating Doppler Weather Radar products in BUFR format.
2.4. Platform and software independent software utility for converting binary and universal
formatted raw data in readable ASCII format is provided.
Note: Regarding procedure of archiving data, please see 3.8, at page No.29.
B.6. Operational limitation
Elevation Limit
OPERATIONAL LIMITATION
There are two pre-limit switches and two final limit switches on the elevation housing. When the
limit switch cam presses on one of the pre-limit switch’s plunger tip, the pre-limit switch sends a
logic signal to the DCU. The DCU prevents the motor from turning forward, but does not
prevent it from turning in the opposite direction. Once the limit switch cam presses on one of the
final limit switch’s plunger tip, the final limit switch sends a logic signal to the DCU, which
inhibits the elevation drive power amplifier output, to further stop the motor. Once the antenna
elevation exceeds the up or down final limit, the two mechanical shock absorbing stops, mounted
on the two sides of the elevation housing, gradually absorb the antenna motion kinetic energy to
ensure the safety of the pedestal system.
Elevation Limit Angles
The elevation limit settings and tolerances (in degrees) are factory set and are as follows:
Pre-limit (+): 90.2º±0.2º Pre-limit (-): -1.2º±0.2º
Final limit (+): 94.0º±0.2º Final limit (-): -2.0º±0.2º
Mechanical stop (+): 95.0º Mechanical stop (-): -3.0º
71

APPENDIX C
C.1. Calibration procedures of panel meters
Control panel meters are to be calibrated. Meter A1P1 indicates filament current. Similar meter
is used for focus coil current. Meter P3 is for indication of Ion pump current.P5 indicates the
charging voltage. Meter P4 is used for series of 15 parameters by means of a selection switch.
The following procedure is to be followed to calibrate the above meters as given in C.1 below.
Figure C.1. Tx Control Panel A1, Panel Meters, Location of Controls and Indicators
1. Set the H.V.Power Circuit breaker Q1, Auxiliary circuit breaker Q2, and cabinet light
power circuit breaker Q3 off.
2. Open the cabinet doors.
3. Remove the charging switch module, A10 from TX bay.
4. Close the right-bay inner door. Set the cabinet light power circuit breaker Q3 and Auxiliary
circuit breaker Q2, and Auxiliary circuit breaker Q2 on and place the Tx in maintenance
mode.
5. Calibrate the +5VDC, +15VDC, -15VDC, +28VDC, and 40 VDC AND Ion pump voltage
according to meter calibration procedures No.5 to No.9 as described in 6.3 of MEHB 10-
511.
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6. Wait for ten minutes. Calibrate the Filament Power Supply Inverse Voltage and meter
voltage according to meter calibration procedures No.11 No.12 as described in 6.3 of
MEHB 10-511.
Table C.1. Location and Calibration of panel meters
No. Position Parameter
1 A1P1 Filament
Current
Calibration method
Adjust PS1A1RP10 to make the reading of A1P1 equal to the filament
current value on the nameplate of klystron V1. Then, use a multi-meter
to measure TP2 of A1A2 and obtain a value X. The values Y, Z and M
are obtained from the formulas Y=(25X)/27.8, Z=32X/27.8 and
M=50X/27.8. Adjust potentiometer A1A2R8 while monitoring pin 5 of
A1A2U8 with the multi-meter and set the voltage equal to Y. Adjust
potentiometer A1A2R20 while monitoring pin 9 of A1A2U8 with the
multi-meter and set the voltage equal to Z. Adjust potentiometer
A1A2R5 while monitoring pin
13 of A1A2U8 with the multi-meter and set the voltage equal to M. With
these steps, the calibration of the Filament current protection is
completed. The over-current value of the Filament is typically 32A and
the under-current value is typically 25A.
2 A1P2 Focus Coil
Current
3 A1P3 Ion Pump
Current
4 A1P4 Charge
Voltage
Adjust PS2A1RP7 to make the reading of A1P2 equal to the focus coil
current value on the nameplate of klystron V1. Then, measure TP3 and
obtain a value X. similar to the calibration method for Filament Current
protection. Y and Z can be obtained according to the formulas Y= (20X)
/22 and Z= 24X /22. Adjust potentiometer A1A2R6 while monitoring
pin 5 of A1A2U6 with the multi-meter and set the voltage equal to Y.
Then, adjust potentiometer A1A2R7 while monitoring pin 2 of A1A2U6
with the multi-meter and set the voltage equal to Z. With these steps, the
protection circuits for Focus Coil Current are now calibrated. The overcurrent
value of Focus Coil Current is typically 24A and the undercurrent
value is typically 20A.
No calibration is necessary.
Measure the PFN Charge voltage at A12XS6 using an oscilloscope and
read the value. Adjust A1A2R3 to make the reading of A1P4 equal to
the value.
5 A1P5/
SA9-1
6 A1P5/
SA9-2
+5 VDC Adjust A1A2R27 to make the reading of A1P5 equal to 5 volts at
position 1 of A1SA9.
+15 VDC Adjust A1A2R28 to make the reading of A1P5 equal to 15 volts at
position 2 of A1SA9.
7 A1P5/ -15 VDC Adjust A1A2R29 to make the reading of A1P5 equal to 15 volts at
73

SA9-3
position 3 of A1SA9.
No. Position Parameter
8 A1P5/
SA9-4
Table C.2. Location and Calibration of panel meters
Calibration method
+28 VDC Adjust A1A2R30 to make the reading of A1P5 equal to 28 volts at
position 4 of A1SA9.
9 A1P5/
SA9-5
10 A1P5/
SA9-6
+40 VDC Adjust A1A2R31 to make the reading of A1P5 equal to 40 volts at
position 5 of A1SA9.
+510 VDC Adjust A1A2R23 to make the reading of A1P5 equal to 510 volts at
position 6 of A1SA9.
11 A1P5/
SA9-7
12 A1P5/
SA9-8
13 A1P5/
SA9-9
14 A1P5/
SA9-10
15 A1P5/
SA9-11
16 A1P5/
SA9-12
Filament
Power
Supply
Inverse
Voltage
Filament
Voltage
Focus Coil
Voltage
Ion Pump
Voltage
Beam
Current
Electron-
Beam
voltage
Measure the peak-to-peak voltage between terminals 1 and 2 of the
terminal board A7A1XT1 using an oscilloscope and read the value.
Adjust A1A2R24 to make the reading of A1P5 equal to the value at
position 7 of A1SA9
Adjust A1A2R32 to make the reading of A1P5 equal to the nameplate
filament voltage value of klystron V1 at position 8 of A1SA9.
Measure the voltage value between terminals 1 and 2 of the terminal
board L1XT1 using a multi-meter. Adjust A1A2R25 to make the
reading of A1P5 equal to the value at position 9 of A1SA9
Adjust A1A2R26 to make the reading of A1P5 equal to 3KV at position
10 of A1SA9.
Adjust A1A2R19 to make the reading of the A1P5 equal to 24
milliamperes at position 11 of A1SA9 with the PRF 322Hz and narrow
pulse.
Adjust A1A2R16 and A1A2R16B to make the reading of A1P5 equal to
60KV at position 12 of A1SA9.
17 A1P5/
SA9-13
Inverse Peak Adjust A1A2R18 to make the reading of the A1P5 equal to 11
Current milliamperes at position 13 of A1SA9 with the PRF 322Hz and narrow
pulse.
18 A1P5/
SA9-14
Charge
Current
Adjust A1A2R17 to make the reading of A1P5 equal to 0.65 amperes at
position 14 of A1SA9 with the PRF 322Hz and narrow pulse.
19 A1P5/ Regulating Adjust A1A2R11 to make the reading of A1P5 equal to 5 milliamperes
74

SA9-15 Current at position 15 of A1SA9 with the PRF 322Hz and narrow pulse.
C.2 Calibration procedure for dynamic range
ZAUTO
This is a command used in the RCP8 to find the dynamic range value. In this method, we first
measure the total noise level of the Signal processor by measuring the equivalent dBZ input with
no test Signal inserted. We will then insert the internal CW test Signal into the input of the
Receiver Protector. The test Signal amplitude will be sequentially adjusted in 1 dB steps over
the full 103 dB Range of the test attenuator. The received equivalent dBZ level for each
attenuator step is recorded to hard disk. The dynamic Range from 1 dB above the noise level to
1 dB above the 1 dB compression level is then calculated automatically and the Dynamic Range
value is displayed on the screen.
Configuration for measuring dynamic range is shown below. The internal RF Generator along
with the 7 Bit Attenuator will generate a set of 104 Signal level steps at 1dB per step. This
stepped Signal is input to the directional coupler on the Receiver Protector, passes through the
normal receive channel and is measured by the RVP8 Signal Processor.
4.3. Test procedure
(1) Type the “zauto” command
Figure C.2. Configuration of Dynamic Range test
(2) Select Pulse Width 2.0 as shown below in Figure 3.
(3) Click the “AutoCal” button to start calibration automatically from the Zauto menu.
The zauto utility steps through a series of signal values and plots the points. Finally the
Dynamic Range is shown in the Results area of the zauto display. Enter the result on the
data sheet and include a screenshot as Attachment 7, Figure 9.
75

MDDS and Noise Figure Test
Figure C.3. An Example Dynamic Range Test Results
To verify the MDDS (Minimum Digital DetecTable Signal) over the Complete Receiver
Chain, the receiver noise level power will be tested first. After that, an external signal will be
injected to the LNA. The receiver output noise level (actually, in this case, test signal plus noise)
will be measured using Zauto while the input signal level is increased. When the receiver output
signal plus noise level is 3 dB higher than the noise only level, the input signal power from the
external signal generator is equal to the MDDS.
Configuration
Connect an external signal generator to the input of the LNA. Set the frequency of the
generator to the site operating frequency. Use a cable with a calibrated loss at the site operating
frequency and account for this cable loss in calculating the input power to the LNA. The signal
will go through the normal Receiver Channel including the RVP8 Digital IF and RVP8 down
conversion process. The Zauto utility will be used to measure the power in the I and Q received
digital samples (see Figure C.4).
Ratio of Reverse and Forward Power (dB)
External signal Generator
Low Noise
Amplifier
Receiver Output on
Zauto
Receiver Channel
Figure C.4. MDDS Test Configuration
76

Test procedure
(1) Type the “zauto” command
(2) Select Pulse Width 2.0 as shown above in Figure 3.
(3) Turn off the external generator output. Click the “Noise” button to take a measurement of
the noise level without signal present. The value is displayed in the “Noise dBm” readout.
Enter the result in the data sheet and include a screen shot as Attachment 7 Figure 4.
(4) Calculate the target output by adding 3 dB to the value measured in step 3 and enter this in
the data sheet.
(5) Set the external generator so the input to the LNA is -117 dBm. Click the “Noise” button
to make a measurement of signal plus noise. Increase the external generator level and
make another measurement of signal plus noise using the “Noise” button. Repeat this until
the “Noise dBm” reading is equal to the Noise plus 3 dB target, 0.03 dB. Enter the
LNA input power at this point in the data sheet and attach a screenshot as Attachment 7,
Figure 5. This is the MDDS.
(6) Calculate the system noise Figure from the equation:
NF = MDDS(dBm) + 114 - 10*Log(.526)
Where :
MDDS = The value measured in step 5.
“.526” = The measured noise bandwidth of the digital matched filter.
Enter the result on the data sheet.
Antenna peak power test procedure
The zcal utility is an alternative to the zauto utility for entering and displaying the The zcal
utility is an alternative to the zauto utility for entering and displaying the LOG receiver
calibration numbers in the calibration file. Zcal can be useful when first setting up a system,
before final calibration. It is also the only way to reset reference calibration information.
Reference information is applicable only on systems that automatically run calibration. (See
chapter 12 on zauto) If a new calibration deviates too much from the reference, it is not used.
This prevents loss of data if the signal generator fails. Zcal requires no graphics interface. You
enter the calibration numbers which have been determined in some other manner. For an RVP6,
these numbers consist of a slope and an intercept in the linear mapping between averaged A/D
converter values and dBZ. For the RVP7 and later, just the intercept is required. There are
separate calibrations for each pulse width and polarization as applicable. A thorough discussion
of the LOG receiver channel calculations is covered in the Signal Processor User’s Manual.
77

2. Summary of the test method
The antenna peak power will be observed at the forward power 30 dB coupler on the top of
the pedestal, which feeds the Antenna. A test cable with calibrated loss will be used along with a
calibrated Power Meter. A special test program will be used in the RCP8 computer to create
constant Transmitter Triggers. The Peak power out will be measured.
3. Test procedure
Antenna Peak Power
(1) Start the system and run the system in the normal operating state.
Elevation
Rotary Joint
Directional
Coupler
Fixed Attenuator
(30dB)
RF
Power Meter
Figure C.5
(2) Run the signal processor testing program, Set pulse width and PRF.
(3) Press the “High voltage On” button to switch on high voltage.
(4) Connect the RF power meter, Agilent N1921A, through a 30dB fixed attenuator to the
forward power connector of the directional coupler as shown in the above Figure 17.
(5) Measure the Peak RF Power.
(6) Press the “High voltage Off” button to switch off high voltage.
4. Test result
PRF and peak power are to be measured for both long pulse and short pulse and recorded.
C.3. ARC Detector Test
This test is conducted to check the detector circuitry functionality.
1. Perform RDA power-down procedures given in 6.52 of manual 510 (given below)
2. Press the LOCAL/REMOTE CTRL switch on the Tx Control panel so that the local
control indicator lights..
3. Press the ARC TEST switch on the TX control panel.
78

4. Observe that the PFN voltage goes to zero, focus coil current goes to zero and high
voltage goes off.
5. Observe that the waveguide arc indicator is illuminated at the fault display panel.
6. Observe that the FAULT and MANUAL RESET indicators at the cabinet top are
illuminated.
7. Press MANUAL RESET switch and FAULT DISPLAY RESET switch.
8. Observe that the three indicators listed in step No.5 goes off.
9. Press the LOCAL/REMOTE CTRL switch on the Tx Control panel so that the remote
control indicator lights up. Restore the system to normal operation by performing the RDA
power-on procedures given in 6.5.3 of manual 510.
79

SCAN STRATEGY IN DOPPLER WEATHER RADAR
APPENDIX D
D.1. BASICS ABOUT SCANNING STRATEGIES EMPLOYED IN DWR OPERATION
With the using of radar to find a target of interest (e.g., a cloud), three pieces of information are
needed:
(1) Azimuth angle (direction relative to north)
(2) Distance to the target of interest
(3) Elevation angle (angle above the ground)
Figure D.1. Azimuth Angle
Figure D.2. Distance to the Target
Figure D.3. Elevation Angle
80

Table D.1. PPI and RHI scanning types
NOTE: Generally in meteorology, radars usually employ one of two or both following scanning
techniques:
Figure D.4. Plan Position Indicator
Figure D.5. Range Height Indicator
Radar Scanning in two orientations
Plan Position Indicator (PPI): The radar holds it elevation angle constant but varies its
azimuth angle. If the radar rotates through 360 degrees, the scan is called a “surveillance scan”.
If the radar rotates through less than 360 degrees, the scan is called a “sector scan”. It’s good
surveillance scan in operational setting. Plan Position Indicator scanning is shown in Figure.D.4
Range Height Indicator (RHI): The radar holds its azimuth angle constant, but varies its
elevation angle. The elevation normally is rotated from near the horizon to near the zenith (the
point in the sky directly overhead). It’s good for determining the vertical structure of the storm.
Range Height Indicator scanning is shown in Figure.D.5
D.2. Scanning Strategies
Doppler Weather Radar, being new generation radar incorporating digital, modular
sophisticated technology, is capable of working in full automatic and continuous mode, 24 hours
for 365 days. It probes the atmosphere according to the schedules/parameters defined to it. The
parameters for scan are defined in its controlling workstation and are loaded in to the onboard
computer of radar. The radar runs the same schedules and scans until it is stopped or modified.
The DWRs network data in IMD is being used by forecasters to issue more accurate and
effective weather forecast especially in Nowcasting.
DWR scans are designed so as to suit the prevailing weather situations and data
requirements. The scans done by radars should satisfy following needs in general:
1. No important event/phenomena/happening in the atmosphere is missed
81

2. Range and Velocity ambiguities do no occur
3. Clutters are minimal if not totally eliminated.
4. High Data Resolution in Range/Velocity/Reflectivity values
5. Minimal noise
6. Scan to scan interval should be such that even the shortest lived phenomena like
Tornado/Thunderstorm are not missed by radar scans.
Ideally, very close-temporal spaced scans (even closer than 5 minutes) enable continuity of
data especially for better rainfall accumulation estimations, volume scans with closely spaced
elevation angles provide better data sets. But both result in high/voluminous data sets causing
data handling/storage problems.
When no weather is expected, far-temporal spaced scans will be enough to monitor the
changes in the atmosphere and to provide nearby clear-air-return based velocity data. Scan
strategy should therefore be different to suit different situations/locations of radar/seasons etc.
The scan schedule for weather seasons like Pre-monsoon season, Monsoon season and Post
monsoon season generally designed as follows:
1. A long range single elevation scan, generally up to 500 km range, with lowest elevation
angle possible is done to have general observation of the atmosphere around the radar site.
2. A medium range (upto 250 km) multiple elevations scan, called a volume scan is done for
detailed probing of atmosphere.
3. RHI scan is set in WSR-98D/S as a real-time display continually or occasionally as
required. This scan is generally done to probe the vertical extent of severe/tall clouds
which is usually seen is Thunderstorms/Cyclones/Norwesters.
D.2.1. Cone of silence
Close to the radar, data are not available due to the radar’s maximum tilt elevation. This
area is commonly referred to as the radar’s "Cone of Silence".
Figure D.6. Cone of Silence
D.2.2. Operation of Doppler Weather Radars in IMD
1. Scientific objectives
82

According to the need of IMD, purpose of Installation and operation of DWR network is to
investigate severe weather, heavy precipitation events with special emphasis on thunderstorm,
squall, microburst, tornado etc. and to generate Nowcasting to the stack holders.
2. Location details of Doppler Weather Radar Palam:
DWR PALAM Location : COORDINATES : 28° 33′ 34″ N, 77 o 04′ 33″ E,
ELEVATION : 226.83m AMSL
The DWR operations and products transmission to the IMD-Central server and FTP server
installed in Mausam Bhawan,Lodi Road, New Delhi are fixed.
The DWR Palam obtains a volume scan consisting 360 degree azimuth sweeps with the
antenna speed 6 rpm. Basically there are two main scan strategy employed for operation of IMD
DWRs, named as IMD-B and IMC C. IMD-B consisting a set of 10 nos of elevation angles
(0.5,1.0,2.0,3.0,4.5,6.0,9.0,12.0, 16.0,21.0) while IMD-C consisting a set of 3 nos of elevation
angles(0.5,1.0,2.0). The scan time for IMD-B is 6.0 min. while for IMD-C is 2.0 min. and total
time for IMD-B & IMD-C, means set of one observation (for both tasks) is 10.0 min. including
2.0 min sleeping time.
D.2.3. Present IMD DWR Scan strategy (DWR-Palam)
Figure D.7. Present Scan strategy in operation at (DWR-Palam) DWR
83

D.2.4. Advantages of Present IMD DWR Scan strategy
1. Overlapping at the lower elevation scan to give a better derived product of Rainfall and
low level wind shear.
2. Closer to VCP21 of NexRad Network, used to detect shallow precipitation It has ten
elevation cuts enabling to perform scan within ten minutes.
3. Cone of silence minimized and less sparse to that of VCP21.
4. High temporal & spatial cover at lower levels – tracing widespread system better.
5. Suitable for generating a mosaic product (especially precipitation) if another radar is
present within 200 – 400 km.
Figure D.8. Cone of Silence 50.0 km around the radar center
Figure D.9. Scan implemented in most of the IMD DWRs
84

Chennai@8min,
Machilipatnam, Vishakapatnam@8min,
Kolkata@13min
Exceptions: DWR Delhi-Palam and DWR Hyderabad@10min
Figure D.10. Cone of Silence in Palam-Radar
Figure D.11. Cone of silence - Palam Radar Enlarged view
85

1. Bins till 2km (configurable) from radar not processed
– Transient time /near field /Receiver sensitivity
2. Data truncated at 20km (configurable) height
– Data volume minimizing/ faster processing
3. Cone of silence below the beam
- increase in lower elevation of beam blockage /Ground returns from side lobe 40%
of crucial/volume of interest not scanned by the radar
Table D.2. Present Scan Strategy at Palam Radar
Parameter
Present
No of scans 10
Number of overlapping 1
Time for one complete volume scan 6
Minimum elevation
Maximum elevation
0.5 deg
21.0 deg
Elevation angles 0.5, 1.0, 2.0, 3.0, 4.5, 6.0, 9.0, 12.0, 16.0, 21.0
PRF
Scan rate
PW
300-600 Hz
12 deg per sec.
1 and 2 micro sec
Increased radar strain ---
Cone of silence ---
Derived product needs
fair
86

D.2.5. Scan strategies being followed by IMD for Doppler weather radars
Table D.3. Volume Scan: IMD_C
Scan Angle
(Elev angle)
(°)
AZ Rate
(°/sec)
(Antenna
Speed)
Period
(sec)
(Auto)
Pulse
Width
Micro Sec
PRF-high
Hz
PRF-low
Hz
No of
Pulses
(Auto)
Max
Range
km
Range Step
km
Vmax
Mps
(Auto)
0.2 18 20 2 300 - 16 500 0.5 7.8
1.0 18 20 2 300 - 16 500 0.5 7.8
Table D.3. Volume Scan: IMD_B
Scan Angle
(Elev Angle)
(°)
AZ Rate
(°/sec)
(Antenna
Speed)
Period
(sec)
(Auto)
Pulse
Width
Micro Sec
PRF-high
Hz
PRF-low
Hz
No of Pulses
(Auto)
Max Range
km
Range Step
km
Vmax
Mps
(Auto)
0.2 8.5 42.35 1 600 450 70 250 0.5 46.9
1.0 8.5 42.35 1 600 450 70 250 0.5 46.9
2.0 8.5 42.35 1 600 450 70 250 0.5 46.9
3.0 8.5 42.35 1 600 450 70 250 0.5 46.9
4.5 8.5 42.35 1 600 450 70 250 0.5 46.9
6.0 8.5 42.35 1 600 450 70 250 0.5 46.9
9.0 8.5 42.35 1 600 450 70 250 0.5 46.9
12.0 8.5 42.35 1 600 450 70 250 0.5 46.9
16.0 8.5 42.35 1 600 450 70 250 0.5 46.9
21.0 8.5 42.35 1 600 450 70 250 0.5 46.9
87

APPENDIX E
E.1. General Safety Requirements
SAFETY AND PRECAUTION SUMMARY
The following are general safety precautions that are not related to any specific
procedures and therefore do not appear elsewhere in this publication. These are
recommended precautions that personnel must understand and apply during many phases of
operation and maintenance.
Keep away from live circuits
Maintenance personnel must at all times observe all safety regulations. Do not replace
components or make adjustments inside the equipment with the high voltage supply turned on.
Under certain conditions, dangerous potentials may exist when the power control is in the off
position due to charges retained by capacitors. To avoid casualties, always remove power and
discharge and ground the circuit before touching it.
Do not service or adjust alone
Under no circumstances should any person reach into or enter an enclosure for the purpose of
servicing or adjusting the equipment except in the presence of someone who is capable of
rendering aid.
Resuscitation
Personnel working with or near high voltage should be familiar with modern methods of CPR.
Such information may be obtained from the local Medical Aid Association. This knowledge may
save a life.
Do not wear jewelry
Personnel performing maintenance on equipment are not to wear watches, rings,
necklaces, bracelets or other jewelry at any time. Electrical arcing can occur when metallic
objects are in the proximity of voltage potentials. Jewelry can become entangled or otherwise
restrict movement causing severe personal injury.
Electrical/Electronic (General)
Voltages used in this equipment can cause arcing and may result in severe burns. Avoid contact
and remove rings, watches, and other jewelry, which may cause personal injury from electrical
shock.
88

High Voltage (Power On)
Avoid contact with high voltage in the equipment, and do not remove safety guards, panels, or
covers in the high voltage area. Severe injury or DEATH may occur upon contact with or in the
proximity of high voltages due to electrical shock.
High Voltage (Power Off)
Avoid contact with the high voltage circuit area. Properly discharge all high voltage capacitors
with the grounding rod. Dangerous high voltages exist when power is turned off and will remain
until discharged. Severe injury or DEATH may occur upon contact with or in the proximity of
high voltages due to electrical shock.
Rotating Equipment
Stay clear of the antenna dish during rotation. Severe injury or DEATH may occur from being
crushed by the antenna dish.
Elevated Work Platform
Use all handrails, safety chains, safety harnesses, safety rails, and ladders properly while
servicing the antenna pedestal and tower. Install all safety equipment and ladders prior to
maintenance tasks. Severe injury or DEATH may occur from impacting the surface below.
Hot Surfaces
Avoid contact with the diesel engine and exhaust pipes during and after engine operation.
Contact with hot surfaces can cause skin burns and other injuries relating to hot surfaces.
Explosive Gas (Fuel)
Clean and remove all fuel spills during engine servicing with absorbent materials or cloths.
Ventilate the area of fuel spills and cleanup. Avoid sparks and open flames in the area. Fumes
may accumulate and explode causing severe burns or DEATH.
Explosive Gas (Batteries)
Always service batteries only in a well-ventilated area. Hydrogen and Oxygen gases may
accumulate during the charging process. Avoid sparks or open flames near batteries. Severe
burns or DEATH may occur due to explosion.
Sulfuric Acid
Wear protective clothing, face shields, gloves, and aprons when servicing batteries. Severe skin
and eye injury may occur upon contact with battery acid. Flush skin and eyes with water
immediately and get medical attention.
89

Cleaning Solvents (General)
Wear protective clothing, safety goggles, and gloves when using toxic cleaning solvents.
Repeated and prolonged contact may cause skin and eye irritation. Flush skin and eyes with
water. Remove clothing saturated with cleaning solvent.
Cleaning Solvents (Inhalation)
Use cleaning solvents only in a well-ventilated area. Avoid inhalation of cleaning solvents.
Asphyxiation or DEATH may occur from prolonged exposure to fumes.
Refrigerant (General)
Wear protective clothing and gloves when servicing the refrigerant of air conditioning
equipment. Contact with refrigerant-filled pipes and fittings may cause severe skin burn.
Refrigerant (Inhalation)
Avoid inhalation of refrigerant. Breathing refrigerant is hazardous to personnel.
Hearing Loss
Wear ear protection near the diesel generator set while in operation. Hearing loss can occur from
prolonged exposure to high noise.
Perform Work Efficiently
When working in areas designated as hazardous, perform work using the proper safety
procedures. Be thoroughly familiar with the procedures required for the task before entering the
area.
Microwave Radiation Precautions
The WSR-98D/S generates and detects electromagnetic energy at a transmitted frequency
between 2.7 GHz and 3.0 GHz. This non-ionizing radiation is concentrated in the antenna beam.
The potential hazard of this radiation to personnel is biological heating. Intense microwave
radiation (power densities greater than 300 mW/cm2) can result in biological damage such as the
formation of cataracts or other opacities in the eyes.
Service personnel must comply with the guidelines given in American Standards Institute
C.95.1-1982 which states that for unrestrictive exposure to microwave radiation the body energy
deposition averaged over the entire body mass for any 0.1 hour period must be kept to less than
144 joules per kilogram (J/kg). This is equivalent to a specific absorption rate (SAR) of 0.4 watts
per kilogram. For the WSR-98D/S frequency band, this corresponds to a power density of 5
mW/cm2.
90

Average power densities less than 5 mW/cm 2 are regarded as safe for indefinite exposure. Power
densities greater than 5 mW/cm 2 should be regarded as potentially hazardous.
Direct Antenna Into Open Area When Transmitting
When it is necessary to perform maintenance with power radiating from the antenna, take the
necessary steps to keep the antenna directed into an open area whenever possible.
Secure All Material When Not In Use
Secure all tools, chassis, and covers before operating equipment.
Restore All Interlocks
Restore all interlock switches to normal operating condition immediately upon completion of
work on the unit involved.
Do Not Use Metal Tools near Exposed Parts
Do not use brushes, brooms, or other tools that have exposed metal parts within 1.2 meter of any
electrical equipment having exposed current-carrying parts.
Do Not Use Ferrous Tools Or Instruments Near Klystrons
Do not use steel or iron tools near klystrons. Such tools may be pulled from the technicians
grasp and may cause damage to the tube.
E.2. Specific Safety Requirements
Tower Safety
To prevent death or severe injury in falling from the tower, the following procedures must be
followed:
• Use hand rails and rest platforms when using the stairs for access to/from Antenna area.
• Ensure that the Antenna floor hatch is closed and secured at all times when not in use.
Electrical Shock Hazards
Prime power voltages and high voltages within cabinets can cause death or severe injury. These
voltages are contained in the generator area, the Radar Data Acquisition (RDA) area and the
Antenna area. Warning signs and labels are located on the guards and barriers to alert personnel
of the potential hazard. DO NOT DISREGARD THESE WARNINGS. Ensure that safety
interlocks, barriers and guards are not bypassed.
In the RDA, the CRT has extremely high voltages present that can cause death or severe injury.
The transmitter high voltage can also cause death or severe injury. Warning labels and interlocks
are present to prevent electrical shock.
91

Radiation Hazard
DO NOT BYPASS INTERLOCKS
Microwave (electromagnetic) radiation exists during the operation of the WSR-98D/S. During all
operational modes, the antenna is scanned continuously. Consequently, the ANSI-designated
power density safety level of 5 mW/cm2 is not exceeded anywhere. However, if the scanning is
stopped for any reason with the transmitter energized, this level may be exceeded within a
cylindrical volume 12.2 meters in diameter and 183 meters long in front of the antenna
reflector, as indicated by the illustration at the end of this safety summary. Maintenance
personnel must not enter this zone when this condition exists, nor should the antenna be pointed
in a direction where there are any people within this zone. Refer to Figure SS-1.
Major Equipment Damage
Mismatching electrical connectors on the RDA can cause major equipment damage. Therefore,
ensure that the connector keys/color coding is followed when reconnecting connectors during
maintenance.
Loss of oil (lubricant) or glycol (coolant) from the generator engine could result in equipment
damage. When performing maintenance, inspect for leaks and tighten fittings as needed. An
automatic over temperature shut-off switch is used to prevent damage.
Removal of Tools
Remove all tools and dropped hardware such as locknuts, washers, screws, etc., from equipment
prior to restoring power to any WSR-98D/S equipment.
Hoist Safety
Before operating the hoist, the operator must be familiar with all operating controls of the hoist,
and must be instructed as to warnings on the hoist and the safe hoisting practices listed in the
operator's portion of the manual provided by the hoist manufacturer.
92

E.3. Antenna/Pedestal Safety
WARNING
Do not attempt to climb or service the pedestal assembly while the antenna is rotating and/or
while the antenna servos are operating. Severe injury from moving elements may result
unless all maintenance instructions and safety procedures are followed.
The antenna/pedestal is provided with safety features and procedures to protect
maintenance personnel from hazards associated with moving masses, dangerous heights, and
awkward equipment access/handling positions. The safety features provided on the
antenna/pedestal assembly include the following:
Safety interlock switch
• Grab bars
• Non-skid surface(s)
• Ladder hooks
• Stow pins
NOTE
The Radome hatch is equipped with safety interlocks. When the hatch (interlock) is opened,
servo power is removed from the Antenna Pedestal and the Transmitter high-power RF
output is switched into the dummy load.
To ensure personnel safety, the following precautions must always be observed:
1. Turn off pedestal power at the RDA Data Processor Maintenance Panel.
2. Place SAFETY WARNING tags on the pedestal electronic ON/OFF switch on the
maintenance panel.
3. Ensure the transmitter is in STANDBY.
4. Place the pedestal "Safe/Operate" switch to OFF.
5. Engage azimuth and elevation stow pins.
6. Use the riser ladder properly secured with quick-release pins when climbing the pedestal to
work inside the azimuth portion of the pedestal.
7. Always use grab bars when climbing the antenna pedestal.
8. Use the appropriate ladder hooks for the ladder for each work area on the antenna
pedestal.
93

ANNEXURE 1
ABBREVIATIONS USED
PRF : Pulse Repetition Frequency
PRT : Pulse Repetition Time
IF : Intermediate Frequency
RF : Radio Frequency
I : In-phase
Q : Quadrature
FT : Fast Transform
FFT : Fast Fourier Transform
DSP : Digital Signal Processor
V : Velocity
Z : Reflectivity
W : Spectral Width
IFD : Intermediate Frequency Digitizer
RX : Receiver
TX : Transmitter
W/G : Waveguide
LNA : Low Noise Amplifier
D : Diameter of Particle
dB : Decibel
dBm : Decibel milli watt
dBZ : Logarithmic Scale for Measuring Radar Reflectivity Factor
V : Antenna Speed
Hz : Hertz
KHz : Kilohertz
MHz : Megahertz
GHz : Gigahertz
LOG : Logarithmic
LIN : Linear
IIR : Infinite Impulse Response
PE : Photo-Electron
CPU : Central Processing Unit
AC : Alternating Current
DC : Direct Current
Rmax : Maximum Unambiguous Range
Vr : Radial Velocity
STALO : Stable Local Oscillator
COHO : Coherent Oscillator
94

ACKNOWLEDGEMENTS
Several experts have been instrumental in allowing this project to be completed. We would like
to express our deepest thanks especially to AVM (Dr.) AJIT TYAGI, Director General of
Meteorology, India Meteorological Department, New Delhi, for his encouragement and patience
throughout the duration of this project. We express our thanks to SH S.K.KUNDU, DDGM (UI),
New Delhi for extending his moral support in fulfilling the given project. Our deep sense of
gratitude to Dr. O.P.SINGH, DDGM, R.M.C. New Delhi, for his support & encouragement. We
would also thank our colleagues S/Shri R. P. Singh A.M.II, Anoop Kandari S.A. & K. K. Sharma
S.A. of Doppler Weather Radar, Palam, New Delhi without whom this project would have been
a distant reality. More suggestions are welcome for improvement on the DWR Palam E-mail ID
dwrpalam@gmail.com from meteorological experts who go through this Standard Operating
Procedure Manual, 2011.
95

REFERENCES
(1). Metstar WSR-98D/S Technical Manuals N0s.500,501,510,511,514.
(2). SIGMET Manuals-7
(3). Module e-radar maintenance and calibration techniques
(4). Radar for Meteorologists,
Ronald E. Rinehart August 199
(5). Radar Handbook,
Merill I. Skolnik
(6). Doppler Radar and Weather Observations,
Doviak R.J. and Zrnic D.S.
(7). Weather Radar Calibration,
R. Jeffrey Keeler January, 2001
(8). Radar Meteorology-
Jürg Joss July.2004
(9). Radar Range Folding and The Doppler Dilemma,
Jeff Haby
(10). Radar Meteorology Doppler,
Heikki Pohjoa, FMI
(11). Principles of Meteorological Doppler Radar,
Distance Learning Operations Course,Instructional
Component 5.3. Ver: 0307
(12). Notes on Radar Basics,
Serkan Eminoglu, TSMS,2004
(13). Weather Radar Maintenance Procedures and Measurements,
TSMS, Aytac Hazer, Cihan Gozubuyuk, 2005
96