Kth - sdr - kit

KTH - SDR - KIT 

KTH – SDR – RECEIVER KIT MANUAL 

1021

6/13/2010 KTH - SDR - KIT Page 1 

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Version table 

Assembly Manual 

KH-SDR Wideband Receiver Kit No-1021 

Version: 2.1 

Date: 26-01-2010 

Auteur: J.v.Scheindelen PE1KTH 

R.W. Engberts PA0RWE 

Version Date Reason By 

1.0 26-01-2010 First issue RWE 

1.1 03-02-2010 Added LT5517 test and solder info and new picture IQ Board RWE 

2.0 20-03-2010 New picture of Synthesizer module, R4, R5 LCD module 

changed. 

Changes are made due to found errors and comments. 

Added Chapter 2.9 Testing the SDR. 

Added Chapter 6.3 Using PowerSDR and Rocky. 

50-70 MHz filter modification added. 

RWE 

2.1 13-06-2010 Changes due to the new firmware version 5.0 RWE 

All rights reserved by KTH-SDR-KIT. No part of this manual may be reproduced, stored in a database or 

retrieval system, or published, in any form or in any way, electronically, mechanically, by print, photo-print, 

microfilm or any other means without prior written permission from the publisher. 

The auteur have used their best efforts in ensuring the correctness of the information contained in this 

manual. They do not assume, and hereby disclaim, any liability to any party for any loss or damage caused 

by errors or omissions in this manual, whether such errors or omissions result from negligence, accident or 

any other cause. 

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Instruction manual KH-SDR wideband receiver Kit No-1021. All rights reserved KTH-SDR-KIT. Software design by PA0RWE.


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Table of Contents 

1. Overview. ....................................................................................................................................3 

1.1 Attenuator module. ..............................................................................................................3 

1.2 HF filter module...................................................................................................................4 

1.3 VHF-UHF module. ..............................................................................................................4 

1.4 I&Q demodulator module. ...................................................................................................4 

1.5 Synthesizer module..............................................................................................................4 

1.6 LCD moduul. .......................................................................................................................5 

1.7 Motherboard module............................................................................................................5 

2 Assembling and installing the modules....................................................................................6 

2.1 Assembling the enclosure (if applicable).............................................................................6 

2.2 Assembling and testing the Motherboard ............................................................................8 

2.3 Assembling and testing the Synthesizer module. ..............................................................11 

2.4 Assembling and testing the LCD module. .........................................................................18 

2.5 Assembling and testing the I & Q demodulator.................................................................24 

2.6 Assembling and testing the HF filter module ....................................................................30 

2.7 Assembling and testing the VHF-UHF module.................................................................39 

2.8 Assembling and testing the Attenuator Module.................................................................43 

2.9 Testing the SDR receiver ...................................................................................................48 

2.9.1 Power consumption....................................................................................................48 

3 KTH-SDR Software installation.............................................................................................49 

3.1 Introduction........................................................................................................................49 

3.2 Installation USB drivers.....................................................................................................49 

3.3 Installation V-USB driver ..................................................................................................49 

3.4 Calibrating the Si570 .........................................................................................................52 

3.5 How to Upgrade the KTH-SDR Firmware ........................................................................52 

3.6 Installation of the Microchip USB driver ..........................................................................53 

3.7 Problem Solving.................................................................................................................55 

3.7.1 No USB connection ...................................................................................................55 

3.7.2 PIC refuses to go into Bootload mode .......................................................................55 

3.7.3 Problems with installing a driver. ..............................................................................55 

4 Specifications............................................................................................................................57 

4.1 Measuring results ...............................................................................................................57 

4.2 Tested SDR software .........................................................................................................57 

5 Adjusting the KTH-SDR .........................................................................................................58 

5.1 Adjusting procedure UHF Helical bandfilter.....................................................................58 

5.2 Adjusting the 140-146 of 137-138 MHz bandpasfilter.....................................................58 

6 Operating Instructions ............................................................................................................59 

6.1 Manually controlled receiver .............................................................................................59 

6.2 Use the receiver as ‘slave’. ................................................................................................59 

6.3 Using of PowerSDR and Rocky ........................................................................................59 

6.3.1 USB / Si570 settings for PowerSDR .........................................................................59 

6.3.2 USB / Si570 Settings for Rocky 3.6 ..........................................................................61 

7 Soldering Technique and Tools ..............................................................................................63 

7.1 Tools needed for SMD soldering.......................................................................................63 

7.2 Soldering the QFN LT5517. .............................................................................................64 

8 Modifications............................................................................................................................67 

8.1 Extention of the 50 MHz filter to 70 MHz (IK0SMG)......................................................67 

9 Pictures......................................................................................................................................68 

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Read this manual attentively before starting assembling the kit, even if 

you are an experienced engineer! 

1. Overview. 

The KTH-SDR Wideband receiver kit 1021, is a Direct Conversion Software Defined Radio covering the 

following frequency bands: 

• HF - covering 3.5 MHz through 32 MHz. 

• 6 meter band - 50 through 52 MHz or 50 through 72 MHz. 

• 2 meter band - 144-146 MHz or 137-138 MHz (optional). 

• 70 cm band - 430-440 MHz. 

The SDR receiver is designed to work as an “All modes” receiver, together with a Personal Computer (PC) 

equipped with a good quality soundcard and SDR software. 

The SDR software makes it possible to demodulate different modes, such as SSB, AM, FM and DRM. 

The receiver is tested with several SDR programs. See chapter 4.2. 

Figure 1-1 gives you an overview of the functional modules and the signal flow. 

All modules are on the upper side of the board connected with RG174 SMB pigtail cables. The I2C signals 

and power supply are put through via the 30-pins card edge connectors on the motherboard. 

The interconnections between the modules are performed over the motherboard. There is no separate wiring 

needed. 

The receiver has a modular set up with a motherboard. There are 4 card modules, a LCD module behind the 

front panel and an attenuator module behind the rear panel. 

The receiver tuning is as desired manual by an encoder mounted on the front panel or via USB and suitable 

software. 

The RF front-end is based on the LT5517 I/Q demodulator of Linear Technology. This demodulator has a 

high IP3 and a wide frequency range from 3.5 MHz through 440 MHz, applied in this receiver. 

The receiver consists of the following 7 modules: 

• Attenuator module 

• HF band filter module 

• VHF-UHF module 

• I&Q demodulator module 

• Synthesizer module 

• LCD module 

• Motherboard module 

1.1 Attenuator module. 

The incoming antenna signal on the BNC connector goes via the Attenuator to the HF- or VHF/UHF 

module. The Attenuator has 4 states: 0 dB, -10 dB, -20 dB en –30 dB and these states can be selected by the 

ATTEN push button on the front panel. The actual attenuation is displayed on the LCD. 

Depending on the actual frequency, the microprocessor selects the right filter module for HF, VHF or UHF 

use. 

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1.2 HF filter module. 

The HF module consists of 7 half octave filters with a frequency range of 3.5 trough 32 MHz and one VHF 

filter for the 6-meter band (50-52 MHz). Switching of the filter sections is accomplished by PIN-diodes and 

controlled by I2C and the PIC controller, depending of the selected frequency. Optional a MAV-11 gainblock 

amplifier can be installed on the HF module to increase the sensitivity of the receiver. 

An addition for 70 MHz is available. 

1.3 VHF-UHF module. 

The VHF-UHF module is equipped with two filters: a 70 cm (430-440 MHz) Helical filter and a 2 meter 

(144-146 MHz) band filter. It is also possible to re-adjust the 2 meter band filter to the Weather satellite APT 

band (136-138 MHz). 

1.4 I&Q demodulator module. 

The LT5517 Quadrature demodulator is taking care of the direct conversion of the antenna signal to a I/Q 

baseband signal which will be connected to the stereo input of the soundcard. The soundcard bandwidth 

depends of the selected sampling frequency and the internal lowpassfilter of the card being used. 

The I en Q signals are, pre-amplified, available by means of 2 RCA connectors behind the rear panel. 

Figure 1-1 Overview of the modules. 

1.5 Synthesizer module. 

The Synthesizer module takes care of the frequency generation and the overall control of the receiver. The 

used controller is a PIC 18F2550 microcontroller and ready programmed for this application. Frequency 

generation is done by a Si570BBB LVDS programmable x-tal oscillator designed by Silicon Labs. The 

Si570 is controlled by I2C to set this device to the selected frequency. 

Because the LT5517 Quadrature demodulator needs a LO signal of twice the receiving frequency, the Si570 

generates a frequency two times the receiving frequency. The frequency displayed on the LCD is half the 

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Si570 output frequency. There is no IF correction because of different IF frequencies applied in the various 

SDR software. 

The PIC microcontroller generates the I2C signals for controlling the modules. These signals are transferred 

via the motherboard en CON4 and CON9 connectors. Frequency control is performed by reading the 24ppr 

encoder or by commands via the USB port. 

Several ports of the microcontroller are used to read the push buttons on the front panel and for switching the 

HF, VHF and UHF band filters and power supply for these modules. 

Keypad use via I2C is optional and not yet implemented. 

1.6 LCD moduul. 

The LCD module PCB is mounted behind the front panel and on this PCB the LCD module and the function 

push buttons are mounted. Next to the push buttons, pull-up resistors are installed. They are useful when the 

R17 resistor array is not used. 

The I2C address of the LCD module is set by 3 jumpers, J1=0, J2=0 and J3=1. 

1.7 Motherboard module. 

The Motherboard module consists of an EURO card size board which fits precisely into the enclosure. 

Access to the USB and RCA connectors is via the front- and rear panel. 

The modules fit in the 30-pole card-edge connectors on the motherboard to prevent separate wiring. The 

LCD- and Attenuator module and also the encoder is connected to the motherboard by flat cable. 

It is up to the user which filter module (HF and/or VHF-UHF) should be used. It is also possible to design a 

filter (or other) module for a specific application to make this SDR kit very flexible. 

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2 Assembling and installing the modules. 

The receiver consists of 7 modules and an enclosure (optional). By assembling the modules in a logical way, 

it is possible to test every module on its own placed in the motherboard connector. In this way you can 

simply check the different voltages from the voltage regulators before start mounting the delicate parts. 

Assembly steps: 

1. Assembling the enclosure 

2. Assembling and testing the Motherboard 

3. Assembling and testing the Synthesizer board 

4. Assembling and testing the LCD board 

5. Assembling and testing the I/Q demodulator board 

6. Assembling and testing the HF Filter board. 

7. Assembling and testing the VHF-UHF filter board 

8. Assembling and testing the Attenuator board 

Note: Read first before you start soldering, the recommendations in chapter 7. 

2.1 Assembling the enclosure (if applicable) 

Tip: Before soldering parts on the Motherboard, it is recommended to use the Motherboard PCB as 

a form for drilling the 4 x 3 mm holes in the lower part of the Enclosure. 

The Enclosure consists of two half aluminum shells and a front- and rear panel. On the lower shell the 

Motherboard is mounted on 4, 10 mm synthetic spacers. The 10 mm height fits with the holes in the front- 

and rear panel. 

In the panels are the required holes drilled and milled for the LCD board, Attenuator board, connectors, 

pushbuttons and encoder. On both panels are placards to give the radio a professional look. 

Put the Motherboard in the middle of the lower shell in a way that on both ends there will be 2,5 mm space. 

Mark the 4 holes on the shell and drill the holes with a 3.2 mm drill. The holes should be exactly between 

two ripples. 

After you have assembled en tested the Motherboard, you can mount it on 10 mm spacers with 4 M3-20 

screws. Don’t forget to mount the 4 stuts below the lower shell! See figure 2.1-1. 

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Figure 2.1-1 

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2.2 Assembling and testing the Motherboard 

Tip: Before soldering parts on the Motherboard, it is recommended to use the Motherboard PCB 

as a form for drilling the 4 x 3 mm holes in the lower part of the Enclosure. 

On figure 2.2-1 you can see the parts that should be soldered on the Motherboard. To reduce the heat in the 

Synthesizer module, the 12Volt supply voltage is lowered by a voltage regulator VR1 to about 8.5 Volt. The 

regulator is mounted at the bottom of the Motherboard. The zener-diode D1 raises the output from the 5V 

regulator to 8.5 Volt. 

Figure 2.2-1 Motherboard schematic with components. 

First solder the SMD parts at the bottom of the board. Check if the code stamp on VR1 is N06B. Use a 

mounting device for the PCB or mount 4 M3-20 screws in the 4 holes to use it as ‘table legs’. Solder the 

parts and connectors on the upper side of the board. 

See figure 2.2-2 and 2.2-3 for details. 

Check that the 10-pole box header connectors are mounted on the Motherboard with the gap to the back of 

the receiver. See figure 2.2-1. 

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Wind the 2 x 10 turns reversed to each other on the toroid L1 with the delivered 0.4 mm wire. Glue a nylon 

ring between the toroid and the motherboard. 

Component list 

C1 = 100n (CAPACITOR 1206 SMD) 




C5 = 10µ/16 (EL-CAPACITOR 1210 SMD) 



C9 = 470µ/16 (EL-CAPACITOR 5.04 MM PAD DISTANCE) 




CON1 = USB-B (USB-B CONNECTOR ASSMANN) 

CON2 = USB-A (USB-A CONNECTOR ASSMANN) 

CON3 = BOX HEADER 2*5 (BOX HEADER 2*5) 


CON5 = CARDEDGE 2*15 (CARDEDGE 2*15 TYCO-5530843-2) 

CON6 = CARDEDGE 2*15 (CARDEDGE 2*15 TYCO-5530843-2) 

CON7 = CARDEDGE 2*15 (CARD CONNECTOR 2*15 TYCO-5530843-2) 

CON8 = CARDEDGE 2*15 (CARD CONNECTOR 2*15 TYCO-5530843-2) 


CON10 = JACK 2.1 mm (JACK CONNECTOR CONRAD No-733954-89) 

D1 = Z3V6 (ZENERDIODE 1206 SMD) 

D2 = 1N4001 (DIODE 1N4001 SEMICRON DO-213AB CONRAD No- 160265-89) 

J1 = RCA CINCH (RCA CINCH PCB CONN CONRAD-736899-89) 

J2 = RCA-CINCH (RCA CINCH PCB CONN CONRAD-736899-89) 

J3 = 2x1 JUMPER (2x1 JUMPER ) 

L1 = TORROID FT50-43 (TORROID FT50-43 AMIDON) 

R1 = O ohm (RESISTOR 1206 SMD) 

S1 = MINI-THUMBLER SWITCH (TUMBLER SWITCH SINGLE POLE) 

VR1 = LM1117-5 (LM1117-5.0 VOLTAGE REGULATOR SOT 223-N06B) 

The diode D2 prevents damage if the power supply is connected in the wrong way. 

Supply 12 Volt to the DC connector and measure the voltage on J3 which should be approximately 8 – 8.5 

Volt. This is not critical. If all parts are installed and the supply voltage on J3 is correct, you can mount the 

motherboard in the enclosure shell as described in Chapter 2.1. 

Mount the front- and rear panel on the lower shell with the self tapping screws and check if the connectors fit 

in the corresponding holes. Correct if necessary the 10 mm spacers by putting a washer between the spacer 

and the shell or by shorten the spacer with a file. 

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Figure 2.2-2 Components on Upper side of the Motherboard 

Figure 2.2-3 Components on Lower side of the Motherboard. 

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2.3 Assembling and testing the Synthesizer module. 

See the schematic on figure 2.3-1. The frequency generation is accomplished by the Si570 clock generator 

made by Silicon Labs and covers 3.5 MHz to 440 MHz. Controlling of the complete receiver is done by a 

Microchip PIC 18F2550. This microcontroller generates I2C data for most of the modules and communicates 

via USB with the host computer. Most of the I/O ports are available on block headers or card edge 

connectors. For initial PIC programming, an ICSP connector is available on the board. Firmware upgrades 

are carried out through the USB port after setting the PIC in ‘Bootload’ mode. There are two LED’s on the 

board: one as a power indicator and the other one for indicating that the PIC is in Bootload mode. 

The 5 Volt power supply can be obtained (set by jumper J1) from the USB port (only for testing the USB 

connection) or from voltage regulator VR1 for normal use. Because the Si570 needs only 3.3 Volt, there is 

also a 3.3 Volt regulator on the board. To adjust the 5 Volt I2C levels from the PIC to the 3.3 Volt level of 

the Si570, a bidirectional voltage translator interface IC2 is used. 

The balanced RF output of the Si570 is adjusted by TR1 to the 50 ohm impedance of the MAV-11 to get for 

the I/Q demodulator LT5517 a stable and strong signal. 

Frequency tuning of the Si570 can be done via USB commands or the 24 pulse per revolution encoder as 

well. 

Pull-up resistors are necessary for the function push buttons connected to the RA-ports. You can place these 

resistors near the buttons on the LCD board, or you can use a resistor array (R17 – not in kit) on the 

Synthesizer board. 

In figure 2.3-2 en 2.3-3 you will see the location of the components. 

Install the components as follows: 

Solder first R3 before the DIL28 IC-socket will be placed. Next, on the backside, solder the 3.3 Volt 

regulator VR2 en the components: D2, C19, C17, C14, C15, L2, C10, C11 and C9. VR2 takes care of the 3.3 

Volt supply of the Si570 and GTL2002. Check if the code stamps on VR2 is N05B. 

Solder the 5 Volt regulator VR1 on the board and next the components C5, C6 and C7. VR1 takes care of the 

5.0 Volt supply of the PIC and also the LCD board. Check if the code stamps on VR1 is N06B. 

Now the regulators and accompanying parts are in place, you can put the module in the motherboard 

connector and connect the 12 Volt DC to the motherboard. 

Caution: When you place a module in the motherboard connector, be sure the 

module is in the corresponding connector and in the right way. Be sure the 

module connector pin 1 and 2 and the Motherboard connector pin 1 and 2 are 

in the same position! If you place a module in the wrong way, it can be 

irreparable damaged! 

Tip: Use a 12 Volt external power supply with a 1 Amp (max) fuse and or use a 

series resistor of about 10 ohm 5 Watt in the DC line for sure. 

Check the 5 Volt and 3.3 Volt on the test points on the Synthesizer board. 

If all the supply voltages are OK, then you can continue with the rest of the components. 

Note: CUT-B and connection A is only applicable if you are using the CMOS version of the Si570 and not 

the provided Si570 LVDS. 

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Between C3 and R7 there should be a wire connection soldered. Be sure to place TR1 in the right way, the 

white dot is facing to the Si570. 

The dot on the MAV-11 is the output and facing to both SMB connectors. 

Both push buttons S1 and S2 are located on the backside of the board, so they are easy to operate. 

When soldering the 20 MHz x-tal, it is recommended to put a piece of cardboard or something similar, 

between the x-tal and the PCB. This is to prevent the possibility of a short circuit between the x-tal housing 

and the pads on the PCB. 

Mount the remaining parts on the backside of the board. 

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Figure 2.3-1 Schematic synthesizer VFO. 

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C1 = 18pF (CAPACITOR 1206 SMD) 





C6 = 10µ/16 (ELCO 10uF/16 DIAM 4x5 MM CONRAD No 421565-89) 














C20 = 2n2 (CAPACITOR 1206 SMD) 





COD1 = 24 P/R (ROTERY ENCODER 24 PULS-360 GRAD) 

CON2 = ICSP (7x1 HEADER ) 

CON3 = BOX HEADER 2x5 (BOX HEADER 2*5) 

D2 = 1N4001 (DIODE SMD) 

D3 = 1N914 (DIODE WIRE) 

IC1 = 18F2550 (PIC 18F2550-I/SP 28 PIN SPDIP) 

IC2 = GTL2002 (LOW VOLTAGE TRANSLATOR SOIC NXP) 

IC3 = Si570-LVDS 1400 MHz (SILICON LABS Si570 BBA000121G) 

IC4 = MAV-11 (MAV-11 GAINBLOK) 

J1 = JUMPER (3x1 HEADER) 

J3 = SMB (SMB 90 GRAD PCB EB2-L174 REICHELT) 

J4 = SMB (SMB 90 GRAD PCB EB2-L174 REICHELT) 

L1 = BLM32A06 (CHOKE MURATA 1206 SMD) 


L3 = 1.8 uH (INDUCTOR SMD 1812CS COILCRAFT) 

LED1 = LED (LED GREEN 3 MM DIAMETER) 

LED2 = LED (LED RED 3 MM DIAMETER) 

R1 = 10k (RESISTOR 1206 SMD) 

R2 = 560 (RESISTOR 1206 SMD) 

R3 = 10K (RESISTOR 1206 SMD) 







R10 = 4k7 (RESISTOR 1206 SMD) 





R15 = 1x150+1x180 SMD PARR (RESISTOR 1206 SMD) 

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S1 = BUTTOM (PUSCH BUTTOM 5.18 MM HOLE) 

S2 = BUTTOM (PUSCH BUTTOM 5.18 MM HOLE) 

TR1 = WBC4-1WLB (BROAD BAND TRANF) 

U0 = DIL 28 (DIL 28 SOCKET) 

VR1 = LM1117-5.0 (LOW DROP 5.0V REGULATOR SOT 223-N06B) 

VR2 = LM1117-3.3 (LOW DROP 3.3V REGULATOR SOT 223-N05B) 

X1 = 20 MHz (X-TAL 20 MHz 49HCU) 

Figure 2.3-2 Components on upper side Synthesizer Board. 

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Picture 2.3-2 Components on upper side Synthesizer Board. 

The Si570 is soldered at last. Make sure that the marking dot on the Si570 is at ‘1’ position on the board. 

The Microcontroller 18F2550 is fully programmed with the SDR control firmware. You can test the 

Synthesizer board after the Encoder and the LCD module is ready and tested. You can read the frequency on 

the LCD and check it with a frequency counter connected to SMB J3. Don’t forget to put a jumper on J1 for 

5 Volt supply to the PIC! 

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Picture 2.3-3 Components on lower side synthesizer print. 

Figure 2.3-3 Components on lower side synthesizer print. 

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2.4 Assembling and testing the LCD module. 

The LCD is installed on a single layer board and should be mounted behind the front panel. Before you 

mount the LCD, first install the 2 wire jumpers and the 3 wire jumpers for the I2C addressing on the noncopper 

side. See figure 2.4-1 and the I2C address settings in schematic figure 2.4-5. 

Note: If the LCD is installed on the module PCB, it is impossible to access the I2C address lines!! 

Figure 2.4-1. Front side LCD board and I2C address jumpers. 

Mount the components on the component side of the LCD module board, the two flat cables and at last the 

LCD module. See figure 2.4-6. 

The first flat cable is connected to the CON4 box header on the motherboard. This cable is for the 12 Volt 

DC supply and the I2C signals controlling the LCD. 

Install the cable in that way the intermediate wires are not connected and the colored wire is on pad one. See 

figure 2.4-2, 2.4-3 and the schematic figure 2.4-5 

The second flat cable is the connection between the push buttons on the LCD module and the box header on 

the Synthesizer module. 

Install the cable in that way the intermediate wires are not connected and the colored wire is on pad one. See 

figure 2.4-2, 2.4-4 and the schematic figure 2.4-5 

Both flat cables are about 4 cm in length. To mount the cables secure to the LCD board, use the supplied tieraps. 

The LCD is mounted with 4 M2 bolts and 4 5 mm spacers to the LCD module board. Don’t forget to add a 

16 pins header strip between the LCD connections and the module board. After the LCD is mounted with the 

4 screws, solder the 16 pin header strip to the LCD and the LCD module board. 

Solder the 4 push buttons below the LCD on the non copper side of the board. 

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Figure 2.4-2 LCD display flat cable connections. 

Figure 2.4-3 Detail LCD display flat cable connection to the Motherboard. 

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Figure 2.4-4 Detail LCD module flat cable connection to the Synthesizer module. 

The encoder has it’s own flat cable and is connected to the box header CON3 on the motherboard. See 

schematic figure 2.4-5 for the right connection of the encoder to the flat cable. 

If you are using an other encoder than supplied in the kit, beware of the right connection the flat cable. If the 

encoder has a switch, you can use it as ‘Tune Lock’ switch and connect the switch to the pads X and Y on 

the LCD module board. 

If you want to change the fase (contrast) of the LCD you can replace R4 and R5 by a trimpot of 5 KΩ. 

Mount the Encoder and the LCD module board to the pre-drilled front panel. Use for the LCD module 4 M3- 

20 bolts and 15 mm spacers. See figure 2.4-7 for details. 

Test the LCD module by connecting the motherboard DC input to your 12 Volt DC source. On the LCD you 

should see a short introduction text with the version of the firmware followed by frequency information and 

the status of the step size and attenuator. If the LCD stays out, switch of immediately the 12 Volt and check 

al the connections, especially the flat cables connections. 

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Figure 2.4-5. LCD schematic and push buttons connections. 

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B1 = MG F35 (THROUHOLE PUSH BUTTON) 

B2 = MGF35 (THROUHOLE PUSH BUTTON) 






C3 = 2µ2/16 (Tantaal Elco) 

CON = BOX HEADER 2*5 (BOX HEADER 2*5 CABLE CONNECTOR) 

CON = BOX HEADER 2*5 (BOX HEADER 2*5 CABLE CONNECTOR) 

IC1 = PDF8574T (I/O EXPANDER I2C SOIC) 

J1 = (JUMPER 3x1 HEADER) 



LCD1 = 2x16 LCD ( LCD 2x16 + BACKL DISPLAYTECH 162A SERIES 72x36 mm ) equivalent. 

R1 = 4k7 (RESISTOR) 



R4 = 4K7 (RESISTOR 1206 SMD) value depend on LCD visibility setting 

R5 = 680 (RESISTOR 1206 SMD) value depend on LCD visibility setting 




Figure 2.4-6 Copper side LCD board (mirrored). 

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Figure 2.4-7 Installation of the LCD display behind the front panel. 

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2.5 Assembling and testing the I & Q demodulator 

The I/Q demodulator module is build on a double layer board. There are two IC’s to mount, the 

LT5517 which has a QFN footprint and the SOIC low noise op-amp LT6231. See the schematic 

figure 2.5-2. 

Power supply is accomplished by two regulators. VR1 for the 5 Volt supply to the LT5517 and 

VR2 for the 10 Volt supply to the LT6231. Because the LT5517 consumes about 80 mA, the heat 

dissipation is divided to VR1 and VR2 as well. Both regulators are SOT223 and soldered for that 

reason on a wide copper field. 

Because soldering of the LT5517 is a very precise job, we start mounting this chip. 

Read and follow carefully the soldering procedure in chapter 7. 

Check proper mounting of the LT5517 as follows: 

When IC1 is on its place and soldered, you can check the solder joints with a Multimeter to 

measure if there is no short circuit between the pads. Use therefore the still not used pads for the 

surrounding components, e.g. C12 and C13. You can use this method also to measure the proper 

solder joints between the chip pads and the copper tracks. There should always be some 

resistance, if not change the measuring pins of your meter and measure again. If again no 

resistance, than the soldering connection is not good and should be done again. 

Note: it is important that the measuring voltage not exceeded 5 Volt and your ohm meter is set to 

> 20 KΩ measuring! Check the voltage on the pins, if possible, with an other Multimeter. 

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Figure 2.5-1 Upper side I & Q demodulator board. 

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Figure 2.5-2 I & Q demodulator schematic. 

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C1 = xx (CAPACITOR 1206 SMD) 









C12 = 27nF (CAPACITOR 1206 SMD) 























D1 = 1N4001 (DIODE 1N4001 SMD) Replace the diode by a piece of wire 

IC1 = LT5517 (LT5517 I&Q DEMODULATOR) 

IC2-A = LT6231 (1/2 OP-AMP SOIC 8) 

IC2-B = LT6231 (1/2 OP-AMP SOIC 8) 

J1 = SMB (SMB 90 GRAD AMPTHENOL-SMBG252B1-3GT30G-50) 

J2 = SMB (SMB 90 GRAD AMPTHENOL-SMBG252B1-3GT30G-50) 

JMP2 = 2x1 jumper (JUMPER 2x1 HEADER) 



P1 = 20k (TRIM POTMETER PANASONIC SMD 20 K-OHM CONRAD No-421054-89) 

P2 = 20k (TRIM POTMETER PANASONIC SMD 20 K-OHM CONRAD No-421054-89) 














___________________________________________________________________________________________________________ 



________________________________________________________________________________ 




TR1 = WBC4-1WLB (1:4 COILCRAFT TRANSFORMER ) 

VR1 = LT1117-5.0 Code stamp N06B 

VR2 = LT1117-5.0 Code stamp N06B 

Figure 2.5-3 Components on front side I & Q demodulator. 

If the LT5517 is soldered correctly, continue with assembling of the next parts. First install the regulators 

VR1 and VR2 followed by the components C21, C33, R17, C35, C32, en C8. D1 should be replaced by a 

piece of wire. Check the code stamp on the regulators: VR1-VR2 5.0 Volt code stamp = N06B. 

Do not install choke L2, to prevent 5 Volt supply to IC1 during testing of the regulators VR1 and VR2! 

Caution: When you place a module in the motherboard connector, be sure the 

module is in the corresponding connector and in the right way. Be sure the 

module connector pin 1 and 2 and the Motherboard connector pin 1 and 2 are in 

the same position! If you place a module in the wrong way, it can be irreparable 

damaged! 

Put the I/Q module in the corresponding connector on the motherboard (watch the pin 1 indicator), and 

connect your 12 Volt DC power supply. Check if the voltage near R14 is 5.25 Volt (half of the 10.5 Volt 

supply voltage from VR2). Check if the voltage near R17 is 10.5 Volt. 

Check on the cooling fin of VR1 if the output voltage is 5 Volt. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

If all the voltages are correct, then continue assembling the remaining parts. Don’t forget to install choke L2! 

You don’t have to install C1, because this is for impedance matching to 50Ω only. 

Take care of the position of TR1. The pin numbers of TR1 are not correctly written on the PCB. Pin 1 and 3 

are changed even as pin 4 and 6. The white dot on TR1 is at pin 1 and is facing to the LT5517. 

Install a short RG174 coax cable on the back side of the board, between J2 and C10. See figure 2.5-4 

Figure 2.5-4 Components on back side I & Q demodulator. 

To adjust the amplification of the op-amps IC2, you can install two 10-turn trimpots P1 and P2 in stead of 

the fix resistors R12 and R13. It is now possible to set the amplification for an optimal result compared to 

your soundcard or to influence the total gain of the receiver from antenna to soundcard. 

You can skip the trimpots and install the fix resistors R12 and R13 if you wish. This setting is good for most 

of the standard on board sound chips. 

If you decide to use the trimpots, then you have to use an oscilloscope or RMS meter to adjust the I and Q 

output exact to the same level. An other possibility is to adjust both trimpots to a desired value by means of 

an ohm meter. 

Install the SMB connectors on both sides of the board, see figure 2.5-3 and 2.5-4. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

2.6 Assembling and testing the HF filter module 

First solder the components VR1, T1 and D38 and the accompanying parts C94, C95, C96, R37, R27, R29, 

R30, C111, C116, C117, R36 en C120. Check if the code stamp on VR1 = N03B. 

Solder the 0Ω resistor below the text MAV-11 on front side of the HF board. This resistor is connected to the 

7 Volt supply. 

The voltage supply is now ready for testing. Put the HF module and also the Synthesizer module (needed for 

testing) in the corresponding connector on the motherboard (watch the pin 1 indicator). 

Connect your 12 Volt DC power supply and check if the receiver starts-up by looking at the LCD. If 

everything looks normal, check if the frequency on the LCD is in one of the HF bands (below 30 MHz). If 

not, select a HF band with the ‘Band’ push button. The supply voltage to the HF module is now switched on 

by T1. 

Check the output voltage of VR1 (7.1 Volt) and the voltage on D38 (5.1 Volt). 

If the supply voltages are correct, you can continue with soldering the band filter parts. 

Warning: the assembling of the HF module is due to the high component density a very precise job. 

Don’t try to haste yourself, because a mistake is easy made….! 

On both sides of the HF board, 4 filter banks are situated. The banks are numbered on the board from 1 to 8. 

IC1 and IC3 are the analogue switches CBT3125 which are switching the filter banks on by means of the 

pin-diodes. If the horizontal diodes of one bank are in forward conduction, then the vertical diodes on both 

sides of the filter are blocked and high-ohmic. All other not in use filter banks are disconnected by the 

vertical pin-diodes. See schematic figure 2.6-1. 

All filter coils are SMD 1812, with the exception of filter 1 and 2. The decoupling coils XL are 100µH and 

size 1008. On the table in figure 2.6-5 you see for each filter bank the required coils and condensers. There is 

no need to wind coils. 

Note on the coils: 

The Coilcraft 1812C filter coils are wind on ceramic forms. The winding wire is spot welded on the solder 

pads of the coil, so be care when soldering the coils. Check the connection after soldering with an ohmmeter. 

Colour code Coilcraft coils 

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________________________________________________________________________________ 

Soldering the Pin-diodes. 

Note on the Pin-diodes: 

On the left side, near J1 on the HF board, you will see in white paint the connection of the BA892 pin-diode. 

The little line indicated with ‘K’ is the cathode and is the same line in the schematic indicated with ‘K’. 

Everywhere on the board where a pin-diode must be soldered, you find that little white line. 

The BA892 has a SCD80 size and is very tiny and vulnerable. For that reason 2 spare diodes are added to 

the kit. Be sure that you solder the diode in the right direction; use a magnifying glass with lighting. Don’t 

heat to long and don’t put to much force on the diode when soldering. 

If you doubt about the right ‘A’ and ‘K’ direction, compare a 1N914 and the BA893 with an ohmmeter. 

Place both diodes on a whit piece of paper, to prevent losing the parts…. 

As desired you can install the MAV-11 gain block. This increased the sensitivity and decreased the noise 

figure of the receiver. A disadvantage is a worse strong signal behaviour (IP3). 

If you don’t install the MAV-11 you have to make a wire bridge from the input condenser C106 to the output 

condenser C114. See schematic figure 2.6-1. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

Figure 2.6-1 Schematic HF filter module. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 















C22 = 6.8pF (CAPACITOR 1206 SMD) 


















C51 = 6.8pF (CAPACITOR 1206 SMD) 
























C94 = 10µ/16 (EL-CAPACITOR SIZE 1812 SMD) 










___________________________________________________________________________________________________________ 



________________________________________________________________________________ 







C116 = 10µ/20 (EL-CAPACITOR SIZE 1812 SMD) 






D1 = BA892 (PIN DIODE SCD80) 
























D25 = 1N914 (DIODE SOT27 (DO35) WIRE) 












D38 = 5 V (ZENER DIODE WIRE) 





IC1 = CBT3125 (1-4 MULTIPLEXER SOIC PHILIPS) 

IC2 = PCF8574T SOIC (PCF8574T SOIC) 

IC3 = CBT3125 (1-4 MULTIPLEXER SOIC PHILIPS) 

IC4 = MAV-11 (SGA-4586 GAINBLOK) 

J1 = SMB (SMB 90 grad AMPHENOL-SMBG252B1-3GT30G-50) 

J2 = Jumper (3x1 JUMPER HEADER) 



J5 = SMB (SMB 90 grad AMPHENOL-SMBG252B1-3GT30G-50) 

L1 = 470nH (INDUCTOR SMD 1206CS-471XJLB COILCRAFT) 

L2 = 820 nH (INDUCTOR SMD 1206CS-821XJLB COILCRAFT) 

L3 = 1 uH (INDUCTOR SMD 1812CS COILCRAFT) 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 





L8 = 1 uH (INDUCTOR SMD 1812CS-102XLJB COILCRAFT) 






L14 = 820 nH (INDUCTOR SMD 1206CS-821XJLB COILCRAFT) 











L25 = 47µH (INDUCTOR SMD 1812CS COILCRAFT) 

L26 = 150nH (INDUCTOR SMD 1812CS COILCRAFT) 

LX1 = 100uH (CHOKE COILCRAFT 1008LS-104XJL SMD) 
















R7 = 10k (RESISTOR) 






R19 = 270 (RESISTOR) 











R37 = 0 (RESISTOR 0 OHM (36 PICES ON THIS PCB) 

T1 = MMBT2222A (TRANSISTOR NPN SOT23 (s1P) 

VR1 = LT1117-ADJ (VOLTAGE REGULATOR SOT223 - NO3B) 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

Figure 2.6-2 Upper side HF filter module board. 

Figure 2.6-3 Component upper side. 

The 1N914 diodes D25, 26, 27, 28, 29, 30, 31 and 32 switching the filter banks and prevent back flow of the 

voltage to the CBT3125. On the upper side of the board 1N914 diodes D27, D28 and D29 are mounted 

above SMD parts. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

Wire bridges. 

On the right-hand of the upper side of the HF board, you will find 4 pads marked as ‘C’. Connect these 4 

pads with a blank piece of wire, or put solder pins in the pads en connect the pins together. Start at R12, then 

to R11, D19 and ending at R9. Add also a wire bridge at L5. 

Add jumpers for the I2C addressing on the header pins J2, J3 and J4 as indicated in figure 2.6-1. 

Figure 2.6-4 Component lower side. 

Both SMB connectors are situated on the lower side of the board. 

Note: 

To prevent mistakes during the installation of the SMD parts it’s a good procedure to assemble one bank at 

the same time, and check it for errors. If possible check the condensers first on the right value before 

soldering them. Check also the colour code on the coils against the code translation table. 

The 0 Ω 1206 SMD resistors are not really resistors but bridges over a print track. They are indicated on the 

board only with ‘0’. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

Figure 2.6-5 HF Filter component table with values per band. 

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________________________________________________________________________________ 

2.7 Assembling and testing the VHF-UHF module 

The VHF-UHF module consists of a double layer board provided with 2 band filters. One filter with 4 

Helicals for the 70 centimeter band (430-440 MHz) and a two coil band filter for the 2 meter band (144-146 

MHz) or Weather satellite band (136-138 MHz). 

There is also the possibility to skip the filters by connecting jumper J1 and J2 to a 50Ω micro strip line on the 

upper side of the board. That gives you the possibility to connect directly the antenna signals via the 

SGA4586 to the I/Q demodulator. See figure 2.7-1. This is a valuable option if you will use this receiver as a 

test receiver. If there is a possibility of overloading, you can switch on the Attenuator. 

Two 50Ω GHz relays RL1 and RL2 are responsible for selecting the VHF or UHF filters, and RL3 connects 

the I/Q demodulator to the HF or VHF-UHF filter. Depending of the selected frequency the micro controller 

switches via RB3 the +5 Volt supply voltage to the module. This +5 Volt supply voltages also excites RL3 

to connect the VHF-UHF module to the I/Q demodulator. 

Switching between VHF and UHF is done by the micro controller port RB4. 

Mount first the components around the +5 Volt supply voltage. See right below on schematic figure 2.7-1. 

VR1 should be mounted isolated on the board. 

Testing 5 volt supply voltage. 

The supply voltage is now ready for testing. Put the VHF-UHF and also the Synthesizer module (needed for 

testing) in the corresponding connector on the motherboard (watch the pin 1 indicator). 

Connect your 12 Volt DC power supply and check if the receiver starts-up by looking at the LCD. If 

everything looks normal, check if the frequency on the LCD is in the VHF or UHF band. If not, select the 

corresponding band by pressing the ‘BAND’ pus button whenever you reached the VHF or UHF band. 

The supply voltage is via T3 connected to the board. Check the +5 Volt near R3. To get some room for 

measuring, you can remove the HF module. 

If the +5 Volt is correct the module can be further assembled with the remaining parts. 

Notes: 

• To prevent short circuit between the relay stand-off part near the ground pin and the pads on the PCB, it 

is recommended to put a piece of cardboard or something similar (0.5 mm) between the relay and the 

PCB. 

• Diode D2 is drawn reversed on the PCB. In figure 2.7-3 of the manual it is OK. 

• R5 and R6 are replaced in the kit by wrong resistors. Use for R5=240 ohm and R6=720 ohm or for 

R5=220 ohm and R6=680 ohm. 

• The trim condenser C7 makes it possible to adjust the coupling factor of the 2 meter band filter to get a 

flat pass band. Because a 3-coil band filter was very difficult to tune, we made the choice to skip L3 and 

C8 and use C7 as trim condenser. L3 and C8 are not shown in the schematic but they are on the PCB 

drawing. See schematic in figure 2.7-1. 

Don’t forget to install the wire bridge below diode D2. See figure 2.7-3 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

Figure 2.7-1 Schematic VHF-UHF module. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 


C1 = 100n ( CAPACITOR 1206 SMD) 






C7 = SMD 1-3 pF (CAP TRIMMER) 







C15 = 10µ/16 (ELCO 10u/16 DIAM 4x5 CONRAD No 421565-89) 




C19 = 10u/16 (ELCO 10u/16 DIAM 4x5 CONRAD No 421565-89) 



D1 = 1N4148 (DIODE 1N4148 WIRE) 

D2 = 1N4148 (DIODE 1N4148 WIRE) 

D3 = 1N4148 (DIODE 1N4148 WIRE) 

D4 = 1N4148 (DIODE 1N4148 WIRE) 

D5 = 1N4001 (DIODE 1N4001 SMD) 

IC1 = SGA4586 (SGA-4586 GAINBLOK MMIC SIRENZA) 

J1 = 3X1 HEADER JMP (3X1 HEADER) 

J2 = 3X1 HEADER JMP (3X1 HEADER) 

L1 = 7HW-42025A-435 (HELICAL FILTER 7HW) 

L2 = 90nH (TOKO MC120 COIL E526HNA-100073) 

L4 = 100uH (CHOKE COILCRAFT 1008LS-104XJL SMD) 

L5 = 7HW-42025A-435 (HELICAL FILTER 7HW) 

L6 = 90nH (TOKO MC120 COIL E526HNA-100073) 

L7 = 1.8uH (TOKO SMD CHOKE 1812) 

P1 = SMB (SMB 90 GRAD PCB) 





R3 = 6K8 (RESISTOR 1206 SMD) 






RL1 = OMRON G6Y-1 5VDC (RF RELAIS G6Y-1 5VDC) 



T1 = MMBT2222A (TRANSISTOR-NPN SOT-23) 



VR1 = LM317-T-ADJ (VOLTAGE REGULATOR TO220) 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

Figure 2.7-2 Component upper side VHF-UHF module board. 

Figure 2.7-3 Component lower side VHF-UHF module board. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

2.8 Assembling and testing the Attenuator Module 

The Attenuator can be used for the HF and VHF-UHF bands as well. I2C controlling is accomplished by 

IC1, PCF8574T. There are 4 states defined: 0 dB, -10dB, -20dB and –30dB and set by the ‘ATTEN’ push 

button on the front panel of the receiver. When the receiver is switched on, the Attenuator is set to 0 dB. 

The attenuator is switched by 50Ω GHz relays and connected to each order by 50Ω micro strip lines. The 

circuit consists of Pi-attenuators build with SMD 1206 resistors. R3 and R9 are 2 resistors connected in 

series. See the schematic on figure 2.8-3. 

VR1 takes care for the 5 Volt supply. 

First solder D2, C8 and C11. VR1 should be mounted isolated on the board. Mount the flat cable on the 

upper side of the board. Install the cable in that way the intermediate wires are not connected and the 

coloured wire is on pad one. See figure 2.8-1 and the schematic figure 2.8-3. 

Connect the Attenuator board with the flat cable to the motherboard box header CON9. Connect your 12 

Volt DC power supply. Check if the voltage near R13 is +5 Volt. If this is correct, add the remaining parts to 

the board. 

Notes: 

• To prevent short circuit between the relay stand-off part near the ground pin and the pads on the PCB, it 

is recommended to put a piece of cardboard or something similar (0.5 mm) between the relay and the 

PCB. 

• Jumper J4 is to select a 100 KΩ resistor for static discharge or to apply 5 Volt to the BNC antenna 

connector to feed an active antenna system. For that use, you have to change the 100KΩ resistor to a 

1mH inductive. 

If all the parts are soldered on the board and the board is tested, you can mount the Attenuator board to the 

rear panel of the enclosure. Use 4 M3-16 bolts with 10 mm spacers. See figure 2.8-4. 

Figure 2.8-5 shows you the cables between the different modules. Two short SMB cables should be soldered 

to the Attenuator board and connected to the VHF-UHF and HF SMB connectors. Check the right place on 

the Attenuator board for both cables. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

Figure 2.8-1 Component upper side Attenuator module. 

Figure 2.8-2 Component lower side Attenuator module. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

Figure 2.8-3 Schematic Attenuator module. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

Figure 2.8-4 Mounting the Attenuator to the rear panel. 

Figure 2.8-5 SMB cable connections between the modules. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 









C8 = 10u/16 (ELCO 10u/16 DIAM 4x5 CONRAD No 421565-8) 



C11 = 10µ/16 (ELCO 10u/16 DIAM 4x5 CONRAD No 421565-8) 





CON1 = BOX HEADER 2*5 CABLE (BOX HEADER CABLE 2x5) 

D1 = 1N4148 (DIODE 1N4148 WIRE) 

D2 = 1N4001 (DIODE 1N4001 SEMICRON DO-213AB CONRAD No-160265-89) 

D3 = 1N4148 (DIODE 1N4148 WIRE) 

D4 = 1N4148 (DIODE 1N4148 WIRE) 

IC1 = PCF8574T (PCF8574T SOIC 16) 

J1 = 3x1 JUMPER (3x1 HEADER JUMPER) 




P1 = BNC (BNC CONNECTOR) 

P2 = SMB (SMB 90 GRAD RG174/U CABEL CONNECTOR) 

P3 = SMB (SMB 90 GRAD RG174/U CABEL CONNECTOR) 

R1 = 100k (RESISTOR WIRE 0.5 WATT) 

R2 = 95.3 (RESISTOR 1206 SMD) 

R3 = 24+47 (2 x RESISTOR 1206 IN SERIE SMD) 

R4 = 95.3 (RESISTOR 1206 SMD) 





R9 = 180+68 (2 x RESISTOR 1206 IN SERIE SMD) 







RL1 = G6Y-1 (OMRON RF RELAIS G6Y-1 5V) 





T1 = MMBT2222A (MMBT2222A (TRANSISTOR NPN SOT23 (s1P)) 



VR1 = uA7805 (VOLTAGE REGULATOR +5.0 V TO220) 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

2.9 Testing the SDR receiver 

2.9.1 Power consumption 

When all the modules are individually tested, you can start the power consumption test based on the 

placed modules. Following you find an overview of the power consumption per activated mosule: 

- Motherboard (MB) with LCD module, no read-out: 6 mA 

- MB + LCD + Synthesizer module: 188 mA. 

- MB + LCD module + Synth. + !&Q module: 305 mA. 

- MB + LCD module + Synth. + I&Q + HF module switched on: 353 mA 

- MB + LCD + Synth. + I&Q + HF + VHF-UHF module switched on and at 144 MHz: 417 mA 

With 440 MHz band switched on: 506 mA 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

3 KTH-SDR Software installation 

3.1 Introduction 

The software (firmware) for the KTH-SDR kit is developed in ‘C’ by PA0RWE, using the free development 

software MPLAB and MCC18 (student version) from Microchip. The USB part is based on the Microchip 

USB framework. Look at Microchip Development Tools. 

The software for controlling the Si570 is based on the design of Fritz Schlunder found on the Internet. The 

PIC is equipped with a bootloader part. This bootloader makes it possible to upgrade the firmware without 

the use of a PIC programmer, but by using the USB connection with your PC. This Bootloader firmware and 

the PC load program is also developed by Microchip. 

The USB device driver is the V-USB device interface developed by Objective Development 

3.2 Installation USB drivers 

Before you can start installing the drivers, you have to download first the required software from the KTH- 

SDR site KTH-SDR kit website. Download the zip-file and extract this file in a map called Kth-Sdr-Kit. All 

needed drivers and control software is now available. See below. 

3.3 Installation V-USB driver 

After all the modules are build and tested, the next step is to install the drivers. Execute accurately the 

following steps. 

• Connect the KTH-SDR to your 12 Volt DC Power Supply and start your PC. 

• The KTH-SDR starts up, what you can see on the information on the LCD. If the LCD stays ‘dead’, 

there is something wrong, so disconnect your Power Supply and check first the Synthesizer module and 

connections. See chapter 2. 

• Connect your KTH-SDR with the delivered USB cable to a free USB port on your computer. 

• If the PIC is working correct, your computer will show you a message that a new USB device is detected 

and that a driver for this device should be installed. If you did not get any message or did not hear the 

typical USB connection sound, then there is a problem with the USB connection. Check the USB cable, 

try an other USB port of your computer. If nothing works try the hints in chapter 3.7 Problem solving. If 

everything is OK, proceed with the next screen. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

• Select: No, not this time and click Next >. 

• The next screen will rise: 

• Select: Install from a list or specific location (Advanced) and click Next >. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

• Browse to your new map for the location of the driver: 

• Click Next > and the installation of the driver starts automatically. The KTH-SDR is operational and you 

can calibrate the Si570 in the next step. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

3.4 Calibrating the Si570 

Because the Si570 has a non-calibrated x-tal inside, it is necessary to determine the exact frequency of the xtal 

needed for the calculation of the output frequency of the Si570 module which is based on that x-tal. For 

this activity you need a frequency counter which is able to count up to 60 MHz. 

• Connect the frequency counter to the extra SMB connector on the Synthesizer module. 

• Run the KTH_SDR.exe Control program which you can find in the Kth-Sdr-Kit\KTH-SDR Control 

folder. See below. 

• Click on the 56.3200 MHz button. 

• Read the frequency from the counter. This should be about 56.3 MHz. 

• Input this counter frequency in the Manual Input field (watch the MHz dot or comma in this field, 

depending of the settings of your PC). 

• Click the Calibrate button. The Si570 is now calibrated. 

• To test it, click the 10 MHz button. Your frequency counter should give exact 10.000000 MHz and the 

KTH-SDR shows 5.000000 MHz in the LCD. If not correct, repeat the above steps. 

3.5 How to Upgrade the KTH-SDR Firmware 

If you receive an upgrade file for the KTH-SDR firmware or it is necessary to reprogram the PIC, please 

follow the next procedure: 

• Unzip (extract) the received file and put it into the ‘Upgrades’ map. See below 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

• Turn the PIC into the Bootload mode by first press the PROG button and then press and release the 

RESET button. Release the PROG button. 

• If the red LED is flashing then the PIC is in Bootload mode. If not, your computer will ask you for the 

Microchip driver. Otherwise try to repeat pressing and releasing the PROG and RESET buttons. 

• If your computer asks you for a driver, please proceed with the Chapter 3.6. If nothing happens go to 

Chapter 3.7 Problem Solving. 

3.6 Installation of the Microchip USB driver 

If the Microchip device driver (needed for the Bootload mode) is not on your computer, follow the next 

steps: 

• After you try to get the PIC in Bootload mode, the screen below will rise. 

• Browse and select the MCHPUSB\Release map. See below. 

And click OK. The driver will be installed. 

• The red LED on the Synthesizer module starts flashing. If not, press the PROG button and then press and 

release the RESET button. Release the PROG button. The PIC should come in Bootload mode. If still 

not, go to Chapter 3.7, Problem Solving. 

• Next the KTH-SDR firmware upgrade file can be loaded into the PIC. Run the program PDFSUSB.exe 

which you can find in the MCHPUSB Driver\Pdfsusb map. See below. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

• Select the option PICDEM FS USB 0 (Boot) in the program screen. If this option is not available, then 

the PIC is not in Bootload mode. Repeat the steps at the beginning of page 49. 

• Click on the Load HEX File button and browse to the Kth-Sdr-Kit\Upgrades map. Open this map and 

select the upgrade hex-file. See below. 

• Double click on the file KTH_SDR_xx.hex (xx = latest version). 

• Click on the Program Device button and wait until the programming is ready. You should see the 

messages below in the message box. 

• Click on Execute. This resets the PIC and the KTH-SDR starts again. 

• Note: for each time you program the PIC by this method, you have to calibrate the Si570 as described in 

Chapter 3.4. 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

3.7 Problem Solving 

3.7.1 No USB connection 

If you don’t get an working USB connection, check the following: 

• Is the USB cable connected to a working USB port? Try possibly an other free USB port. 

• Try if possible an other USB cable. 

• Try to connect to a free USB port on an other computer. 

• Check the solder connections around the USB connector on the Motherboard. 

• Check the solder connections around the PIC on the Synthesizer board 

3.7.2 PIC refuses to go into Bootload mode 

If you don’t get the PIC in Bootload mode, check the following: 

• Does the KTH-SDR starts up normally, that means that you see information on the LCD and it is 

possible to tune the receiver. If not, check the Synthesizer board. 

• Is it possible to reset the PIC with the RESET push button? If the PIC doesn’t reset, check the solder 

connections around the RESET button S1. 

• Is the PROG button working? Check the solder connections around the PROG button S2. 

3.7.3 Problems with installing a driver. 

If you have the feeling that there is a problem with one of the USB device drivers, you can follow the 

procedure to remove the driver information in the registry. 

Warning: Carry out the following steps only when you are familiar with editing the registry by means 

of the program Regedit. If you make any mistakes, your computer maybe stops working!! 

• Disconnect the USB cable. 

• Run via START – Run, the program Regedit. See below. 

• Open the map HKEY_LOCAL_MACHINE 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

• Open the map: SYSTEM \ CurrentControlSet \ Enum \ USB 

• Click with your right mouse button on the key: Vid_04d8&Pid_000b 

• Choose Permissions…. and select Allow Full Control. 

• Click OK. 

• Click again with your right mouse button on the key: Vid_04d8&Pid_000b and click on Delete. 

• Repeat these actions for the key: Vid_16c0&Pid_05dc 

• The driver information for the Microchip and V-USB driver is now removed. 

• Connect the USB cable between the KTH-SDR and your computer. 

• Proceed with Chapter 3.3 and 3.6 

___________________________________________________________________________________________________________ 



________________________________________________________________________________ 

4 Specifications 

• 7 HF overlapping sub octave band filters, 3.5 - 32 MHz. 

• VHF band low 50 - 52 MHz or 50 – 72 MHz. 

• VHF band high (option) 137 - 138 MHz or 144 - 146 MHz. 

• UHF band 430 - 440 MHz. 

• RF attenuator 0, -10, -20, -30dB. 

• I&Q output 90º faze shift baseband 0 - 48 KHz. 

• Manual tuning or via USB commands. 

• Tuning step sizes 10, 25, 100Hz, 1, 10, 12.5, 48, 96, 100, 

192KHz and 1MHz. 

• Tuning lock 

• Band selection 1 trough 13 van 80 meter trough 70 cm. 

• Frequency memory places 44. 

• LCD display 2x16 backlight. 

• Power supply 12 Volt DC. 

• Key board is not implemented is firmware. 

4.1 Measuring results 

• IP3 figure without pre-amplifier +27,5 dBm 

• IP3 figure with pre-amplifier +15.1 dBm 

• Hf noise floor with standard soundcard (500Hz) - 120 dBm (-146.9 dBc/Hz). 

• SFDR is respectively (500 Hz) 98.4 dB / 90.1 dB 

• Dynamic range 105,8 dB. 

Note: The measuring results are also depending of the used Soundcard and the GAIN setting (P1 and P2) of 

the I/Q pre-amp on the I/Q module. 

4.2 Tested SDR software 

• PowerSDR (all versions with USB-Si570 addition) 

• Rocky 3.6 

• WinRad 

• SDR-Radio Console 

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5 Adjusting the KTH-SDR 

Only the VHF and UHF filters have to be tuned. The best way to do this is by using a Spectrum Analyser 

with sweep option. If no Spectrum Analyser is available, tuning of the filters is also possible with a Signal 

generator and an Oscilloscope. 

The easiest way to tune the filters is to lift the module above the motherboard by using a extension board. 

This board (about 6 cm high and 4 cm wide) can easily made by a piece of PCB with 2.54 mm copper stripes 

and a 30 pole card edge connector. This board fits in the motherboard card edge connector. An other option 

is to solder 50Ω RG174 coax to the input and output of the filters and connect them to your measuring 

equipment. 

5.1 Adjusting procedure UHF Helical bandfilter. 

All modules are placed in the motherboard connectors and connected to each other by the SMB pigtail cables 

according to figure 2.8-4. This is to add the impedance effect of all the modules to the measuring. Proceed 

with the following procedure: 

• Connect the 50Ω Signal generator to the BNC antenna connector P1. 

• Connect an Oscilloscope to the I or Q output RCA connector. 

• Select the attenuator to 0 dB. 

• Tune the Signal generator to 435 MHz and increase the output to 100 mV on the scope. 

• Tune the Signal generator to 430 MHz and adjust both Helicals to a minimum of 70 mV (= -3dB) on the 

scope. Repeat this procedure also for 440 MHz. 

• Adjust as long as necessary that no improvement can be reached and the top of the filter is as flat as 

possible. On the edges of the filter the amplitude may not decrease more than -3 dB. 

5.2 Adjusting the 140-146 of 137-138 MHz bandpasfilter. 

Solder a small wire on the header pins J1 and J2 to connect the filter to the relays. The filter can be used for 

the 2 meter band (144-146 MHz) and the Weather Satellite APT band (137-138 MHz) as well. The coils are 

connected to each other by C5 and C7. 

C7 has to be adjusted in a way that the filter top is as flat as possible. More capacity means a to firm 

coupling resulting in a dip in the curve. To little capacity causes a to sharp filter curve. 

Before you start adjusting the coils, be sure for what frequency band the adjustment is needed! By repeated 

tuning the cores of the filters, you can achieve a nice curve with at both end no more signal decrease than -3 

dB. 

Warning: the cores of the MC120 coils have a hexagon hole. They are very vulnerable!! Use a 

well suitable trim tool, turn the cores very carefully and hold your tool upright! 

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6 Operating Instructions 

After all the modules are completed and tested and the VHF/UHF band filters are tuned, the receiver is ready 

to use! 

The receiver can be used on two different manners: 

• Manually controlled with the use of any kind of SDR software 

• As a ‘slave’ receiver, controlled by SDR software supporting USB and Si570 (PowerSDR / Rocky). 

6.1 Manually controlled receiver 

Connect the KTH-SDR receiver to your 12 Volt Power Supply. The receiver starts up. 

Connect the KTH-SDR receiver to your Computer Line-in input with the delivered audio cable. 

Run a SDR software program at your choice and set this program to use the Line-in input. 

Manual control the receiver. The available functions are: 

- Manual frequency control by means of the Tuning knob on the front panel 

- The step size will be automatically set by the selected frequency band, but can also be manually set by 

pressing the STEP push button and select the desired step size with the tuning knob. 

- Select an amateur band by pressing the BAND push button and select the desired amateur band with the 

tuning knob. The accompanying band filter and module is automatically switch on. The band indication 

is displayed on the LCD. You can change also the start-up frequency of the selected band which is 

automatically stored in memory. 

- If you need some attenuation due to strong signals, you can switch the Attenuator on with the ATTEN 

button. There are 4 settings available: 0, -10, -20 en -30 dB. 

- It is possible to store a selected frequency by means of using the MEM button. 

o To save a selected frequency press the MEM button and select with the Tuning knob an empty 

memory place or a memory place that should be over written. The number of the memory place is 

showed right below in the display (Mxx). If OK, release the button and the frequency is stored. 

o To read back a stored frequency, press shortly the MEM button. Right below on the display you can 

see the number of the memory location. Browse with the Tuning knob to the stored frequency and 

press again shortly the MEM button. The stored frequency became the actual frequency. 

6.2 Use the receiver as ‘slave’. 

Connect the KTH-SDR receiver to your 12 Volt Power Supply. The receiver starts up. 

Connect the KTH-SDR receiver to your Computer Line-in input with the delivered audio cable. 

Connect the USB cable between the KTH-SDR receiver and the computer. 

Run a SDR software program with USB and Si570 support, e.g. PowerSDR or Rocky and set this program to 

use the Line-in input, USB and Si570 (frequency 2x) control. 

The receiver is now fully controlled by the SDR software. You can choose to lock the Tuning knob 

by pressing the TUNE LOCK button. You see a ‘#’ marker left of the frequency on the display. 

If your SDR is in BAND mode when using the USB SDR software, the SDR is automatically 

switch off the BAND mode to prevent unwanted frequency changes of the earlier selected band. 

6.3 Using of PowerSDR and Rocky 

PowerSDR and Rocky can be used to control the SDR receiver. The tested software is 

downloadable from the KTH-SDR information site. 

6.3.1 USB / Si570 settings for PowerSDR 

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Some hints for using PowerSDR. 

Note: It is not necessary to use the Tuning knob of the SDR rx. All frequency tuning is done by 

PowerSDR. 

USB connection 

Before you run PowerSDR, you must switch-on your SDR rx and connect it to your computer. You 

should hear the well known USB sound. Now you can run PowerSDR as well. 

USB setup 

Make the settings as shown above. The Fxtal(MHz) setting is the real frequency of the internal x-tal 

of the Si570. This frequency is used by PowerSDR to calculate the register settings for the Si570 

which are sent to the SDR. 

Frequency update 

If you select a frequency in PowerSDR and you tune up or down, it is not so that at the same time 

the SDR VFO will be updated. VFO updates are done every time you reach the end of the 48, 96 or 

192 KHz bandwidth (determined by your soundcard). 

For that reason the frequency on the LCD is not equal to the frequency on the PowerSDR display 

and jumps after you have reach the mentioned bandwidth. 

Check the receiving frequency 

Check the receiving frequency with a RF generator. If the difference between the generator and the 

PowerSDR frequency is greater than 15 KHz than you maybe listening on the mirror frequency. 

Change the I and Q connector. Make sure that the signal strength of the carrier on the correct 

frequency is (much) higher than on the mirror frequency. 

If the difference is little, than you have to correct the Fxtal frequency by changing it about 10 KHz. 

To tell the SDR that frequency has been changed, switch to an other band and return to the original 

band. You will see that the receiving frequency is changed a bit. Repeat this until the generator 

frequency is equal to the PowerSDR frequency. 

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6.3.2 USB / Si570 Settings for Rocky 3.6 

Some hints for using Rocky 3.6. 

Note: It is not necessary to use the Tuning knob of the SDR rx. All frequency tuning is done by 

Rocky. 

USB connection 

Before you run Rocky, you must switch-on your SDR rx and connect it to your computer. You 

should hear the well known USB sound. Now you can run Rocky as well. 

USB setup 

Make the settings as shown above. You can use Single Band as Multi-Band as well. 

Frequency update 

Rocky is not working at the same way as PowerSDR. Rocky uses fixed VFO frequencies and you 

can tune with Rocky within the 48, 96 or 192 KHz bandwidth, depending of your soundcard 

settings. 

Single Band 

If you choose Single Band than you are able to input a frequency (in Hz). When you push the OK 

button, this frequency is sent to the SDR rx. You can see that on the SDR LCD. 

Multi-Band 

If you choose Multi-Band you don’t have to input each desired frequency but you can select a 

frequency from a list. The selected frequency is sent to the SDR rx as well. You can call the list by 

pushing the menu button right from the frequency display of Rocky. 

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To add frequency to the Multi-Band list, you have to edit the Rocky.ini file in the Rocky directory. 

You can add a new frequency, but take care of the special format. Look at the already listed 

frequencies in the file. 

Calibrating Rocky 

To calibrate Rocky, first choose a frequency (Single or Multi). Then open (after Starting the Radio) 

the Tools / Si570 Calibration window and input the frequency shown on the LCD of the SDR rx. 

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7 Soldering Technique and Tools 

Soldering of SMD parts is workable if you have experience but also by using suitable tools. It is not possible 

to properly solder SMD parts when your PCB is not stable on your workbench. 

Don’t use adhesive tape to secure the PCB on your table. This tape leaves glue rests behind resulting in bad 

solder joints. Buy or make a PCB assembly frame. 

When you are assembling a double sided PCB it is necessary to keep the already soldered parts free from 

your table. Then a assembly frame is essential. You can buy one or make it yourself. See figure 7-1 and 7-2 

for an example. 

7.1 Tools needed for SMD soldering. 

• Magnifier with proper lighting 

• soldering iron with a round, flat pen of about 2.5 mm. 

• a small soldering iron pointed pin of about 0.3 mm which fits in the hole below IC1 on the I/Q PCB. 

• A small soldering iron chisel shape pin, 1.2 mm wide. 

• A PCB assembly frame to fix the PCB and to turn the PCB in a vertical position. 

• Solder flux 

• Flux-cored solder 0.5 – 0.7 mm 

• Tweezers, right angle and straight 

• De-Soldering braid 

• Hot air soldering iron 

• Multimeter 

• Right angle pliers 

Figure 7-1 Example of a home made assembly frame with a revolving press-pin to fix small IC’s. 

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Figure 7-2 A handy anti-static assembly frame, made by AOYUE 

7.2 Soldering the QFN LT5517. 

Every one has it’s own soldering skill. The described soldering procedure could be used for soldering the 

LT5517. 

The LT5517 must be soldered on the I/Q module PCB. This is a very accurate job and should be well 

prepared. 

It is preferred to start soldering the LT5517 before any other parts are soldered on the PCB. 

The LT5517 has an Exposed Pad in the middle which also should be grounded. This pad is also used as heat 

sink. There is a hole in the PCB to solder the pad from the lower side through the PCB. 

Start tinning the pads on the PCB where the LT5517 should be located. Don’t use to much but also don’t use 

to little tin on the pads! With to little tin you run the risk of bad solder joints but with to many you can 

introduce short cuts during soldering. So be care!! 

Tinning is best done by rotating the PCB in a vertical position. Use a soldering iron with a flat pin of about 

2.5 mm. 

Spread some Flux on the pads and tinning the pads by moving the solder iron with the flat side of the pin 

from up to down. 

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Warning: Tinning should be done very fast (in about 1 second) to prevent releasing the copper pads 

from the board. If that happens, your PCB became unusable!! 

Check if the solder on the pads is equal on every pad. If not, repeat tinning (without solder!) in the same 

vertical position. If a hot air soldering iron is available, use this to make the tin fluidly. If still to many 

solder, use de-Soldering braid and make the tin fluid shortly by the hot air iron. Don’t heat the PCB longer 

than 1 or 2 seconds!! 

Before soldering the LT5517, mark the position of pin 1 with correction fluid (TipEx). 

Spread some flux on the pads of the LT5517, don’t forget the sides. Put the IC on the PCB pads, and with 

pin 1 on the ‘1’ marked on the PCB. Use a tool to fix the IC on it’s place and check with a magnifier if all 

the pads of the IC are right placed on the PCB pads. Check and re-check!! If you are sure that the IC is right 

placed, then solder the IC with the hot-air solder iron by first heat-up the PCB around the IC and then to the 

IC itself. 

In a moment you will see the tin flow out and the IC sink into the solder. Stop heating! 

Check the solder joints with a magnifier lamp if they are well soldered and the solder is flowed against the 

side pads of the IC. See figure 7-4. If this is OK and the solder joints are checked on short circuits or bad 

joints (see chapter 2.5), the next step is to solder the Exposed Pad through the hole in the PCB. 

To prevent during soldering the Exposed pad the IC comes off the PCB, put the PCB with the IC flush on the 

table and hold it under a light pressure. Solder with a sharp soldering iron pen and a little tin, the Exposed IC 

Pad to the PCB. See figure 7-5. 

Figure 7-4 Soldering the QFN on the copper side. 

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Figure 7-5 Soldering the “exposed IC pad” through an open VIA. 

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8 Modifications 

8.1 Extention of the 50 MHz filter to 70 MHz (IK0SMG) 

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9 Pictures 

Figure 9-1. Bottom shell with the PCB’s 

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Kth - sdr - kit

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