TH-D72A/E - N3UJJ

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6 OPERATIONAL EXAMPLES OF APRS6.1.1.2 Entering CharactersCharacters can be entered using the encoder or 10-key numeric keypad as you would when textingfrom a cell phone.Further details of important functions follow.6.1.2 Decay Algorithm FunctionIf the position beacon for a mobile station is configured to be transmitted at a fixed time interval, itwould be inefficient use of air-time to continue transmitting at this fixed interval when traffic is slowmoving.The beacon transmission interval gradually increases by using a decay algorithm, thuscleverly reducing air-time used by the station.Traffic Jam!Transmits theposition beaconInitial interval: 1 minute2 minutes 4 minutes 8 minutes 16 minutes 32 minutes 32 minutesFigure 6-1 Decay AlgorithmDecay Algorithm steps the transmission interval of the beacon down from 1 (if the automatictransmission interval is set to 1 minute) to 2 to 4 to 8 to 16 to 32 minutes when the mobile station is notmoving. On the TH-D72A/E, when the interval for automatic transmission is greater than that of DecayAlgorithm, the automatic transmission interval is used. The speed at which Decay Algorithm decidesthat the car is parked can be set using the “Stopped” dropdown list in the Basic tab of the APRSwindow of the MCP-4A programming software. If the mobile station’s speed is less than this setting,then Decay Algorithm will start. The speed setting can be changed only in the MCP-4A program.6.1.3 Proportional Pathing FunctionThis function automatically changes the transmit packet path (relay route) as the automatictransmission interval elapses while traveling. The function substantially reduces load on the entirenetwork by maintaining the packet update frequency at the automatic transmission interval for nearbystations that do not require relaying, while thinning the number of relay hops for distant stations thatdo not require frequent updates.Transmitsevery 1 minuteTransmitsevery 1 minuteTransmitsevery 1 minuteTransmitsevery 1 minuteTransmitsevery 1 minuteTransmitsevery 1 minuteTransmitsevery 1 minuteDIRECT(No hop)WIDE1-1(1 hop)DIRECT(No hop)WIDE1-1,WIDE2-1(2 hops)DIRECT(No hop)WIDE1-1(1 hop)DIRECT(No hop)WIDE1-1,WIDE2-2(3 hops)Figure 6-2 Example of path switchover operation of Proportional Pathing(when the packet path is set to WIDE1-1, WIDE2-2)The speed at which Proportional Pathing decides that the car is moving can be set using the Movingdropdown list in the Basic tab of the APRS window of the MCP-4A programming software. If themobile station’s speed exceeds this setting, then Proportional Pathing will start. The speed settingcan be changed only in the MCP-4A program.42 CONTENTS TH-D72A/EFrom The N3UJJ.COM Document Library
6 OPERATIONAL EXAMPLES OF APRS6.1.4 Simultaneously using Decay Algorithm and ProportionalPathingRefer to the diagram below to understand what occurs when both Decay Algorithm and ProportionalPathing are used at the same time.Velocity (Knots)Status0 23 35321Decay Decay Proportional Proportional Proportional Proportional DecayNowProportionalPathingReturnsto DecayAlgorithmFigure 6-3 Switching between Decay Algorithm and Proportional Pathing(when Stopped = 1 (knot); Moving = 3 (knots))As the example above shows, when the mobile’s speed exceeds 3 knots, Decay Algorithm stops andProportional Pathing begins. Similarly, when the mobile’s speed drops below 1 knot, thenProportional Pathing stops and Decay Algorithm begins.Note: The Stopped value cannot be configured higher than the Moving value. Also, the Moving value cannot be configuredlower than the Stopped value.6.1.5 SmartBeaconing (Written by Steve Bragg, KA9MVA)SmartBeaconing was developed by Mr. Steve Bragg, KA9MVA, and Mr. Tony Arnerich, KD7TA, in1998. SmartBeaconing uses the speed information that is received from the GPS receiver andtraveling direction to efficiently transmit the beacon. There are two factors that come into play whendetermining how SmartBeaconing functions: distance traveled since last beacon transmission,addressed by using Variable Rate Beaconing to change the transmission interval with speed, andheading change since last beacon transmission, referred to as Corner Pegging.6.1.5.1 Variable Rate Beaconing (Transmission Interval Changes with Speed)When your mobile station is moving at a speed less than LOW SPEED as set in the menu, theposition beacon repeatedly transmits at the interval of SLOW RATE as set in the menu. When yourmobile station is moving faster than HIGH SPEED as set in the menu, the position beacon repeatedlytransmits at the interval of FAST RATE as set in the menu. And if your mobile is traveling at anyspeed between LOW SPEED and FAST SPEED, then the beacon transmits at an interval that varieslinearly according to the speed traveled. The transmission interval extends longer as the speedbecomes slower, and the interval becomes shorter as the speed gets faster.Table 6-1 Relationship between Speed and Beacon Transmission IntervalOver HIGH SPEEDSpeedFAST RATETransmission IntervalUnder HIGH SPEED(Only when HIGH SPEED ≥ LOW SPEED)Over LOW SPEEDFAST RATE x HIGH SPEED / current speed = transmission interval time(Only when HIGH SPEED ≥ LOW SPEED)Under LOW SPEEDSLOW RATETH-D72A/E CONTENTS 43From The N3UJJ.COM Document Library
Page 1 and 2: TH-D72A/EFrom The N3UJJ.COM Documen
Page 3 and 4: About Registered Trademark• Windo
Page 5 and 6: CONTENTS1 DEVELOPMENT CONCEPT .....
Page 7 and 8: PROLOGUEAmateurs Building the New G
Page 9 and 10: 1 DEVELOPMENT CONCEPTFollowing is t
Page 11 and 12: 1 DEVELOPMENT CONCEPT1.3 Other New
Page 13 and 14: 2 HOW YOU ENJOY APRS WITH TH-D72A/E
Page 23 and 24: 3 PREPARATIONS FOR OPERATING APRS3.
Page 33 and 34: 4 GPS4.1.2 Datum (Geodetic Survey S
Page 35 and 36: 4 GPS4.2.4 Settings for Geodetic Su
Page 37 and 38: “Time, Altitude, Travel direction
Page 39 and 40: 4 GPS4.3.5 Internal GPS Unit SaveIf
Page 41 and 42: 4 GPSPressing the [TNC] key again i
Page 43 and 44: 4 GPS4.3.9 Mark WaypointYou can reg
Page 45 and 46: 5 APRS SOFTWARE FOR YOUR PC5.1 UI-V
Page 47 and 48: 5 APRS SOFTWARE FOR YOUR PCFigure 5
Page 49: 6 OPERATIONAL EXAMPLES OF APRSWhile
Page 53 and 54: 6 OPERATIONAL EXAMPLES OF APRSBy ch
Page 55 and 56: 6 OPERATIONAL EXAMPLES OF APRS6.1.6
Page 57 and 58: 6 OPERATIONAL EXAMPLES OF APRS6.1.6
Page 59 and 60: 6.2 Base Station (Weather Station)6
Page 61 and 62: 7 APRS NETWORKS7.1 APRS ServersIn t
Page 63 and 64: 7 APRS NETWORKS7.3 Let’s Send Ema
Page 65 and 66: 7 APRS NETWORKS7.4 Digipeaters (Dig
Page 67 and 68: 7 APRS NETWORKSAlthough UITRACE usi
Page 69 and 70: 7 APRS NETWORKSthe same time also h
Page 71 and 72: 7 APRS NETWORKS7.5.3 STATE/ SECTION
Page 73 and 74: 8 MCP-4A MEMORY CONTROL PROGRAM (FO
Page 77 and 78: 8.3 Reading a FileThis section desc
Page 85 and 86: 9 HOW TO UPDATE FIRMWARE9.3 How to
Page 87 and 88: 10 MISCELLANEOUS TOPICS10.1 AvMap (
Page 89 and 90: 11 APPENDIXRevision HistoryRevision
Page 91 and 92: We would like to extend our sincere

TH-D72A/E - N3UJJ

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