aprs is a registered trademark bob bruninga, wb4apr 1 aprs.org aprs dayton 2014 may 2014 maps –...

APRS is a registered trademark Bob Bruninga, WB4APR

11

APRS.orAPRS.orgg

APRS Dayton 2014APRS Dayton 2014

May 2014

Maps – Mobiles - Users

Human to human info exchange!

APRStt !!!

Appalachian Trail Golden Packet Event


Who is WB4APR?Who is WB4APR?

22

1970

1980

1990

2007

2010

2012

Future?

2009

2013


What can I do?What can I do?

33

Energy and Ham Radio are both HUMAN Interest Activities!


44

APRAPRSS

Human to human info exchange!

Single channel info-resource! What you ARENT SEEING anymore… (frustrations) http://aprs.org...

Single H.R. Info Resource Channel …aprs-tactical.html Universal Text Messaging Initiative …aprs-messaging.html

Local-Info (Freq Objects) …localinfo.html

Cave-Link Radio – 1 mi in Mammoth Cave …cave-link.html Golden Packet Event (20 July 2014) … at-golden-packet.html

APRStt (Touchtone for any HT) !!! …aprstt.html

at Dayton

for SAR

AVRS! (universal voice network) …avrs.html


55

Universal Ham Radio Text Messaging Initiative 2010

DTMF

APRS

wireless

cell

26 separate systems!

Send/RX anytime, anywhere, any device by callsign


66

Universal Texting – Lots’a Radios!

TH

-D

72A

VX-8R &

VX-8DR

All now come with GPS BUILT-IN!

VX

-8G

R

FTM-350R


77

D72, D710 and FTM-350 all TX their D72, D710 and FTM-350 all TX their voice Freq and can QSY with one voice Freq and can QSY with one

button…button…

FREQUENCY OBJECTS and POSITS


88

APRS on ANY radio! APRS on ANY radio! (using the RC-(using the RC-D710)D710)

On IC-2820 On IC-2820 DSTARDSTAR

Jeff KB2M

RC-D710 DISPLAY

APRS channel DSTAR channel

Plu

g-n

-pla

y A

udio

C

onnect

ion


99

APRS on ANY radio! APRS on ANY radio! (using the RC-(using the RC-D710)D710)

Attached to an ALINCO HT

Simple SPKR/Mic connections

NiCd Battery Pack


1010

TRACKERS TRACKERS (Now are two-way!)(Now are two-way!)

TT4 with $34 display and AVMAP G5 GPS

And should ALWAYS include their voice contact frequencyh in their packets

Argent Data Systems


1111

Other APRS radiosOther APRS radios Alinco DR-135T/EJ-41UAlinco DR-135T/EJ-41U

2 M Radio with optional 2 M Radio with optional TNC. TNC.

N1VG Scott makes an OT tracker N1VG Scott makes an OT tracker modulemodule

No messaging/data displayNo messaging/data display But OT adds GPS map displayBut OT adds GPS map display VX8R available since Dec 08VX8R available since Dec 08. .

Has GPS built-into speaker micHas GPS built-into speaker mic

Or HAMHUD on any Or HAMHUD on any radio!radio!


1212

OLPC -One Laptop Per ChildOLPC -One Laptop Per Child

$100 laptop per 3rd world kid$100 laptop per 3rd world kid Low power, no moving partsLow power, no moving parts High power WI-FI and MESH High power WI-FI and MESH

netnet Runs LinuxRuns Linux Sound Card to DC, volts, Sound Card to DC, volts,

O’scopeO’scope Jack, KG4GJY’s APRS app:Jack, KG4GJY’s APRS app:

APRS for ALL Portable Terminals & Phones!


Cave-Link Radio (APRS underground)

2 March 2013 Mammoth Cave



2 March 2013 Mammoth Cave Not Waveguide!... UHF

best!


Cave-Link (APRS 1 mi underground)



1717

National Trail Golden Packet National Trail Golden Packet EventEvent

26 July 200926 July 200925 July 201025 July 2010

2000 Miles

15 Stations

Two HOP7-7 paths

Golden Packets end-to-end

Omni Antennas

aprs.org/at-golden-packet.html

Others can Monitor!


1818

Appalachian Trail Golden Appalachian Trail Golden PacketPacket


1919

Appalachian Trail Golden Appalachian Trail Golden PacketPacket


2020

Using Google Earth for LinksUsing Google Earth for Links50,000 miles of national linear trails!50,000 miles of national linear trails!


2121

Appalachian Appalachian Trail Trail

Golden PacketGolden Packet

KX4O John Huggins Complete RF Link Analysis!


2222

Hike Across Maryland(40 miles)Case Study in

proper use of APRS and 144.39

All data/info on 144.39 MHz.

All participants TX on 144.99 & RX on 144.39

Using ALT-INPUT on 144.99 (+600)


2323

30% of 144.39 TX packets captured

97% of 144.99 packets captured

Triple Performance using +600

On 144.99 the digi input only hears the 20 event participants

On 144.39 a digi input hears over 300 users in 5 states (10 times the QRM).

http://aprs.org/HAMsupport.html

Using ALT-INPUT on 144.99 (+600)


2424

Hike Across Maryland(40 miles)Location/time of

over 100 runners reported by APRS messages.

Hams (youth < 23) agreed it was as easy as Texting or Tweeting.

Using an HT to report ALL 100 runners!


2525

What is APRS?What is APRS? APRSAPRS = Automatic = Automatic PacketPacket

ReportingReporting System System (not position (not position tracking!)tracking!)

APRSAPRS since late 1980's was for local since late 1980's was for local tactical digital communications,tactical digital communications, situational awareness and situational awareness and TWO-WAYTWO-WAY information exchangeinformation exchange

Messages + maps for OBJECTS – Messages + maps for OBJECTS – everyone sees the same situation everyone sees the same situation and Network Connectivityand Network Connectivity

A single A single Reference Resource Reference Resource for all for all HAM activitiesHAM activities

Not just GPS Vehicle Tracking!Not just GPS Vehicle Tracking!


2626

Aa

The APRS NetworkThe APRS NetworkInformation exchange between everyoneInformation exchange between everyone

Multiple Hops

And to the Internet Gateway

Digipeaters


2727

Global Mobile/HT Global Mobile/HT PositionPosition and and TextingTexting Connectivity Connectivity


2828

Seeing the NetworkSeeing the Network(PHG data shows relative station performance)(PHG data shows relative station performance)

50 mi


2929

FINDU.COM (FINDU.COM (click to see all stations on click to see all stations on

mapmap))Google for “USNA Buoy” Select USNA-1

40 miles

Also:

APRS.fi

OAPRS.net

Etc…


3030

Seeing the Situation Seeing the Situation (Symbol (Symbol Atributes)Atributes)


3131

Symbol AtributesSymbol Atributes

The original Overlayable Symbols

Since April 2007, all alternate symbolsmay now have overlays

Note, some popular “aprs” programs do not display ANY of these 11 attributes on any map! They show meaningless ICONS instead


3232

APRS-IS (FINDU – Near)APRS-IS (FINDU – Near)Google for “USNA Buoy” Select USNA-1

* Click to see all stations on map


3333

APRS-FI APRS-FI (anyone can see APRS)(anyone can see APRS)

Google for “USNA Buoy” Select USNA-1


3434

APRS-IS (FINDU - Messages)APRS-IS (FINDU - Messages)Google for “USNA Buoy” Select USNA-1

Also:

APRS.fi

OAPRS.net

Etc…


3535

What is APRS all about?What is APRS all about?(Humans communicating INFO with Humans)(Humans communicating INFO with Humans)

Immediate local digital and graphical information exchange Immediate local digital and graphical information exchange between all participants in a local area or event. This includes:between all participants in a local area or event. This includes:

PositionsPositions of all stations and objects of all stations and objects StatusStatus of all stations of all stations MessagesMessages, Bulletins and Announcements, Bulletins and Announcements WeatherWeather data and data and telemetrytelemetry DF bearingsDF bearings and and signal strengthssignal strengths for quick transmitter hunting for quick transmitter hunting RF Connectivity RF Connectivity plots of all stationsplots of all stations LocalLocal OBJECTS OBJECTS on a common map display for all userson a common map display for all users Local Local Freqs, IRLP, ECHOlink, Winlink, Nets, Meetings, events, HamfestsFreqs, IRLP, ECHOlink, Winlink, Nets, Meetings, events, Hamfests

Typical applications are:Typical applications are: Routine local awareness of all ham radio events and assets around youRoutine local awareness of all ham radio events and assets around you Marathons, races, events and public serviceMarathons, races, events and public service Search and rescueSearch and rescue Family communications and tracking and one-line emailsFamily communications and tracking and one-line emails Mobile-to-mobile global text messagingMobile-to-mobile global text messaging Weather data exchange and displayWeather data exchange and display Efficient multi-user Satellite communicationsEfficient multi-user Satellite communications


3636

Scope of Scope of APRSAPRS

Over 40,000 users Over 40,000 users worldwide.worldwide.

RELAYS every 20-30 RELAYS every 20-30 mi called mi called “digipeaters.” “digipeaters.”

All linked by home All linked by home station Igatesstation Igates

Global links by Global links by Amateur Satellites Amateur Satellites

Thousands of Thousands of Weather stations Weather stations

Telemetry and data Telemetry and data everywhereeverywhere

But, only 2% of local ham radio users…

(a side show)…


3737

APRS = Events, Info and APRS = Events, Info and Objects!Objects!

Dayton Hamvention


3838

APRS MisConceptions!APRS MisConceptions!

That APRS is just Vehicle Tracking instead of a That APRS is just Vehicle Tracking instead of a Real-Time Information Distribution Real-Time Information Distribution

SystemSystem.. That APRS is dependent on GPS for its value That APRS is dependent on GPS for its value (GPS is not needed. See Objects)(GPS is not needed. See Objects).. Failure to use the APRS built-in Failure to use the APRS built-in Mile-MarksMile-Marks for tracking all other non-APRS mobiles. for tracking all other non-APRS mobiles. Using APRS clients that only do maps and ignored Using APRS clients that only do maps and ignored too many of the APRS fundamentalstoo many of the APRS fundamentals.. Ignored the fundamental Ignored the fundamental Decay AlgorithmDecay Algorithm to accelerate new data, and decay old data! to accelerate new data, and decay old data! Failure to understand the importance of OBJECTS: . See Failure to understand the importance of OBJECTS: . See ObjectsObjects 101 101 and and OperationsOperations Failure to use real-time messaging: . See Failure to use real-time messaging: . See Messages 101Messages 101 and and Message OperationsMessage Operations Failure to implement the original APRS Centralized Failure to implement the original APRS Centralized Common Bulletin BoardCommon Bulletin Board concept. concept. Not understanding the APRS operator’s role as a Not understanding the APRS operator’s role as a Data InputData Input (Objects, Bulletins and (Objects, Bulletins and

Messages)Messages) Not using the D7 and D700 as Not using the D7 and D700 as data entry and clipboard display unitsdata entry and clipboard display units at field events. at field events. Too much focus on Too much focus on Large ScreenLarge Screen DisplaysDisplays –vs- –vs- IndividualIndividual Operator Operator displays fordisplays for events. events. Failure to display APRS Failure to display APRS symbols with all their attributessymbols with all their attributes and colors without clicking and colors without clicking

them them Failure to manage the network by Failure to manage the network by adjusting the local digipeateradjusting the local digipeater for the situation at hand. for the situation at hand. Not realizing the importance of Not realizing the importance of Voice OperatingVoice Operating frequenciesfrequencies in APRS. in APRS.

See aprs.org/APRS-tactical.html


3939

APRS Growth APRS Growth Opportunities!Opportunities!

Global Email Global Email Done! (WU2Z) - Done! (WU2Z) - Now Universal Text MessagingNow Universal Text Messaging (any device) (any device) CQSRVR CQSRVR (Global APRS CQ’s)(Global APRS CQ’s) Done! (AE5PL) Done! (AE5PL) & ANSRVR& ANSRVR (KJ4ERJ) (KJ4ERJ) APRSttAPRStt (APRS touchtone) – (APRS touchtone) – APRS for Every RadioAPRS for Every Radio Done! (Done! (W4PC of CSSIW4PC of CSSI))

Simple Simple DTMFDTMF memory for your Callsign – memory for your Callsign – One Button SendOne Button Send APRSttAPRStt receiver converts to APRS receiver converts to APRS Position, Time, Frequency and Status!Position, Time, Frequency and Status! On On IRLP IRLP nodes, nodes, EcholinkEcholink nodes, some repeaters, nodes, some repeaters, anywhere on 146.58anywhere on 146.58

AVRSAVRS (Automatic Voice Relay System) (Automatic Voice Relay System) Global Callsign-to-callsign VOIPGlobal Callsign-to-callsign VOIP Uses APRS message to set up call – Uses APRS message to set up call – APRS knows where you and callee areAPRS knows where you and callee are Automatically links to Automatically links to EcholinkEcholink or or IRLPIRLP for for nearest nodenearest node and sends to APRS and sends to APRS APRS Radio APRS Radio auto-QSY’sauto-QSY’s to make link (= Ham Radio Cell phone from Mobile) to make link (= Ham Radio Cell phone from Mobile) (90% D710)(90% D710)

AI-FI AI-FI (APRS WIFI) in every laptop(APRS WIFI) in every laptop OLPC message client (OLPC message client (APRS-XOAPRS-XO) and XASTIR ) and XASTIR (50% …)(50% …) Other Systems Other Systems (View on OpenAPRS, APRS-fi, FINDU)(View on OpenAPRS, APRS-fi, FINDU)

APRS RFIDAPRS RFID for ARRL name tags (event locating) for ARRL name tags (event locating)


4040

Global Global Mobile/HT Mobile/HT

VOICE VOICE ConnectivitConnectivit

yy

AVRSAVRS((

www.aprs.org/avrs.html

))

We can do this now We can do this now with a little software with a little software

and some incentive by and some incentive by a good author!a good author!


4141

Global APRS Global APRS Email!Email!

APRS Global APRS Global Text MessagingText Messaging since 1993; from HT’s since since 1993; from HT’s since

1998!1998! Send Email from any APRS radio anywhere to anyone on Send Email from any APRS radio anywhere to anyone on

the planet, anywhere LIVE.the planet, anywhere LIVE. WU2Z Email Engine on the APRS-IS gates it to InternetWU2Z Email Engine on the APRS-IS gates it to Internet Great Demos. Great Demos. Send an Email to a Blackberry in the Send an Email to a Blackberry in the

audience.audience.

To: EMAIL

MSG: [email protected] ET call home!

New Initiative!New Initiative! Universal Amateur Radio Text Messaging


4242

APRS Msgs/Email

Send/Receive messages or email

Anywhere on the planet via APRS satellite

MSG menu

Confirmation of Relay =>


New APRS New APRS SMS SMS

4343


4444

APRS APRS Global Global CQ’sCQ’s

We needed a CQ System for We needed a CQ System for SCOUTS, JOTA, SATERN, IOTA, SCR SCOUTS, JOTA, SATERN, IOTA, SCR andand Field Day! Field Day! AE5PL AE5PL responded with responded with CQSRVRCQSRVR Allows anyone to send a global message to everyone involved in an Allows anyone to send a global message to everyone involved in an XXXXXXXXXX

activityactivity Just send a message to Just send a message to CQSRVRCQSRVR starting with starting with CQ XXXX CQ XXXX messageCQ XXXX CQ XXXX message EveryoneEveryone who has sent a similar who has sent a similar CQ XXXXCQ XXXX message to CQSRVR message to CQSRVR will get your CQwill get your CQ

From then on, once you see From then on, once you see callsigns,callsigns, you message normally you message normally point-to-pointpoint-to-point To limit load, only one CQSRVR message per 30 minutes is forwarded.To limit load, only one CQSRVR message per 30 minutes is forwarded.

Can also be used any day, any time, anywhere! Can also be used any day, any time, anywhere! CQ CQ CQ CQ anyone around?CQ CQ CQ CQ anyone around? Can also be used for Can also be used for global GROUP commsglobal GROUP comms if 30 minute timer is changed. if 30 minute timer is changed.

www.aprs.org/cqsrvr.html


4545

• CALLSIGN preloaded in DTMF memory: CALLSIGN preloaded in DTMF memory: WB4APR =WB4APR = A9A2B42A7A7C79#

• This is converted to an APRS packet on the APRS channel as:This is converted to an APRS packet on the APRS channel as:WB4APR-12>APRStt,WIDE1-1:!DDM_.__N/DDDM_.__W$146.58MHz HAMvention

• Puts you on global map near Hara Arena, with your immediate calling frequency, your Tone and your Echolink node number and that a Hamfest is going on.

That is everything you need to be known to the Global APRS system!That is everything you need to be known to the Global APRS system! Exists since 2001 (in DOS w DTMF chip). Now we have a Hardware Version! Exists since 2001 (in DOS w DTMF chip). Now we have a Hardware Version!

ByonicsByonics Also Needed in Echolink, IRLP, repeater controllers - ANYTHING with a DTMF Also Needed in Echolink, IRLP, repeater controllers - ANYTHING with a DTMF

decoderdecoder

APRStt gives 100% situational awareness participation not just the 10% with APRS APRStt gives 100% situational awareness participation not just the 10% with APRS

radios.radios.

Other Positions:Other Positions: #B95*234*1D => Milemark #234 on Route 95, northbound

See aprs.org/aprstt.html

APRStt (Touchtone) APRStt (Touchtone) (every (every radio!)radio!)


4646

APRStt (APRStt (hardwarehardware)) See aprstt.html

Marathon

MM

Converter

And PACE

generator

Byonics

DTMF

Add-on

To TT4


4747

Simple DTMF memory - One button puts you in APRS (Simple DTMF memory - One button puts you in APRS (Position, Frequency and StatusPosition, Frequency and Status)!)! DTMF on voice freq translated to packet on APRS channel (or direct to APRS-IS)DTMF on voice freq translated to packet on APRS channel (or direct to APRS-IS) Position is .1 mile LIST on map display adjacent to repeater or FREQ objectPosition is .1 mile LIST on map display adjacent to repeater or FREQ object Frequency used is inserted in packet (for return contact)Frequency used is inserted in packet (for return contact) If Echolink, IRLP or Autopatch, APRS packet includes node or Phone number!If Echolink, IRLP or Autopatch, APRS packet includes node or Phone number! All responses in VoiceAll responses in Voice

APRStt (special event) APRStt (special event) (every (every radio!)radio!)

See aprstt.html


4848

DTMF Report shows on APRS!DTMF Report shows on APRS! CALLSIGN with date and timeCALLSIGN with date and time Position LIST in vicinity of repeater or APRStt entry pointPosition LIST in vicinity of repeater or APRStt entry point Voice Operating Frequency, Tone and local other infoVoice Operating Frequency, Tone and local other info Node number if Echolink or IRLP, or reverse patch number if RepeaterNode number if Echolink or IRLP, or reverse patch number if Repeater

DTMF users show on DTMF users show on mapmap

See aprstt.html

147.105MHz T107 R30m


4949

APRStt (APRStt (HamventionHamvention) ) (Doug Quagliana)(Doug Quagliana)

See aprstt.html


5050

APRStt!APRStt!

Dayton Hamvention


5151

APRSttAPRStt2x2 digit2x2 digitreporting!reporting!

Dayton

B2XXYY*


5252

APRStt (APRStt (Simple Simple

GatewaysGateways))See aprstt.html

As simple

as adding a DTMF chip to a Micro-Trak

Or adding a DTMF chip to an OT and HT for use in the field at a special event


5353

APRStt (APRStt (Freq DisplayFreq Display)) See aprstt.html

For events, put one on each operating frequency and set posits along unused edge of map.

See who is operating where, on what frequency and when


5454

APRS Event Data EntryAPRS Event Data Entry

Score Message Sent

Score Data Received


5555

APRStt for SAR XXX-APRStt for SAR XXX-YYYYYY

Using ANY Radio with a DTMF keypad

SAR groups are PRO’s at using the UTM grid.

It gives resolution:

2 digits – nearest km

3 digits – nearest 100m



APRStt: B3XXXYYY*


5656

APRS (APRS (RFIDRFID))See aprs-rfid.html

For big events, put one at each checkpoint or venue.

Every clubhouse/EOC door

See who is operating where, on what frequency and when

Hot Spot floor mat


5757

APRS (APRS (RFIDRFID) ) (2011)(2011)

See aprs-rfid.htmlHot Spot


5858

APRS Voice Alert! APRS Voice Alert! **

Voice Alert is effectively 3Voice Alert is effectively 3rdrd Radio Radio channel for the D7 and D700 APRS channel for the D7 and D700 APRS radiosradios

By setting the By setting the APRS Band AAPRS Band A to CTSS-to CTSS-100100, , but but keeping the volume turned up:keeping the volume turned up: You wont hear any packets on 144.39 *You wont hear any packets on 144.39 * But you will hear a voice call using PL-100 on 144.39But you will hear a voice call using PL-100 on 144.39 And you will hear* an occasional Ping packet if another And you will hear* an occasional Ping packet if another

D700 comes in line-of-site to you, like a proximity radar D700 comes in line-of-site to you, like a proximity radar alerting you to local presence.alerting you to local presence.

Great for long haul traveling and meeting other APRS Great for long haul traveling and meeting other APRS users.users.

(For all mobiles!)(For all mobiles!)


5959

APRS – IS - Local Info! APRS – IS - Local Info! (Freqs)(Freqs)Last 100 stations!

Direction & Distance

Frequency and Tone


6060

The New-N Paradigm 2004The New-N Paradigm 2004 APRS Generic Paths evolved over 13 years and the presence of many old legacy formats and procedures were really bogging down the network making it saturated and unreliable in busy areas.

In 2005 all old paths were declared obsolete (RELAY & WIDE) and the entire APRS system in the US was then focused only on the WIDEn-N type of generic paths with small values of N.

WIDEn-N goes N hops outward in all directions.

N=2 in most areas colored on next slide

Factor of 3 to 5 improvement!Factor of 3 to 5 improvement!

50% of repeaters still not configured right!50% of repeaters still not configured right!


6161


6262

APRS APRS (PHG Range Circles)(PHG Range Circles)


6363

APRS APRS (ALOHA circle and digipeater hops)(ALOHA circle and digipeater hops)[Your ALOHA circle is your 100% saturated channel range][Your ALOHA circle is your 100% saturated channel range]


6464

APRS APRS Range circles and Path tracingRange circles and Path tracing


6565

APRS APRS ( DFing by signal strength )( DFing by signal strength )


6666

APRS APRS ( Solo DF Fade Circle Technique )( Solo DF Fade Circle Technique )


6767



6868

APRSAPRS Balloons Balloons

Very Simple

APRS transmitter

GPS


6969



7070



7171



7272

APRS APRS 3D views for Balloon tracking3D views for Balloon tracking


7373

APRS APRS Tracking with MilemarksTracking with Milemarks


7474

APRS – APRS – Traffic Speed PostsTraffic Speed Posts

Shows speed of traffic past special points


7575

APRS is INFO.APRS is INFO.not just tracking!not just tracking!

Voice Alert?

AVRS (Ham Radio Mobile Cell via

APRS=>VOIP)?

Signal Finding?

Nets?

Meetings

?

APRStt?

Frequency?

Field Data?

Traffic?RF Range?

Tracker-Voice?

Milemarks?


7676

APRS Emergency APRS Emergency CommsComms

Google for “USNA Buoy” Select USNA-1

Satellite-Simulated Emergency Test – SSET

- Send an emergency Email via Satelilite

Meteor-Scatter Monitoring Network (6 meters)

- Dozens of Igates monitoring 50.62 MHz

- Message Throughput in minutes

- Using surplus 110 Watt 6m radios

- Simple 100’ long wire gain antennas


7777

APRS APRS EmergencyEmergency

Power Power200W Solar Power

- Continuous

10 kW gas Generator 220 VDC

- Auto-runs as needed

- lightweight wires

Low Cost

$1 Universal Power Connector


7878

APRS Home PowerAPRS Home Power

Solar Power.. It aint

what it used to be! 40% drop in price this year

1% what it cost in 1970

95% efficient now (no batteries (70%))

50% total cost Government Rebates!

$500-$3000 annual rebates

FREE Electricity for LIFE

Low Cost

$1 Universal Power Connector


7979

2010

Solar Power Now!

Down to $3/watt installed (1$/W deals)

My 8,000 Watt system (shown)

APRS Home PowerAPRS Home Power


Solar Power = Emergency Solar Power = Emergency PowerPower

COMPLETELY DIVORCE any thoughts of COMPLETELY DIVORCE any thoughts of “emergency power” from Economical power.“emergency power” from Economical power.

Solar power Solar power is for is for ECONOMICAL POWERECONOMICAL POWER

Emergency power has nothing to do with Emergency power has nothing to do with it whatsoever. it whatsoever. (Solve that problem separately) (Solve that problem separately)

8080

aprs is a registered trademark bob bruninga, wb4apr 1 aprs.org aprs dayton 2014 may 2014 maps –...

Documents

aprs human

aprs dayton

wb4apr cavelink radio

kg4gjys aprs app

aprs radios alinco dr

r slide

callsign slide

dtmf aprs wireless cell