Fun With APRS
See what you missed if attending the APRS build was not in your plans. Here you will find three videos that constitutes the fun and learning in store for those who love tinkering with amateur radio.
These videos are on UARC’s YouTube channel.
APRS-1-Intro <<<< click here (09:24) is a the presenter’s, Aidan Kern, an EE student at WVU, description of the origin and the spinoff that resulted in an open source APRS module that you can plug into your typical HT.
APRS – Build Overview <<<< click here (02:13) is Aidan’s brief review of the actual APRS module build process.
Available soon APRS Bench Build <<<< click here Yours truly, N0DVT, photographing the fun and games so took the project home and made this video to demonstrate the actual sequence of build events including: board population and soldering, required Arduino sketch changes and upload to the NANO, and finally some fine tuning of the module’s audio output.
A photo gallery s linked here >>>> APRS build
Aidan provided these build notes:
1. Add a “solder blob” or jumper between NANO pins D2 & D3 (bridging them together).
2. The potentiometer on the board allows for an audio output (to the radio) adjustment to prevent over-deviation and/or distortion.
3. The code-base has Five main parts to be adjusted. All of them are at the beginning of the code file except the Message.
3.1 Callsign (input your callsign, all caps)
3.2 APRS Symbol (only the standard aprs images can be used, they are encoded via a bespoke character, some may also require an escape character—usually “\”)
3.3 Transmit time (where each increment of 100 adds a minute between transmit times, e.g. 100 = 1 minute, & 300 = 3 minutes)
3.4 Transmit offset (the value will make it transmit that number of seconds after the minute e.g. 14 will transmit on 11:37:14 or 16:21:14)
3.5 Message (message is roughly around line 200 in the code. It may have a string/variable output also, please remove that if it is present. I believe that aprs standard has a maximum of 64 characters for this).
4. When the system is setup correctly, upon a reset or power cycle, the radio should quickly key and un-key twice—no data will be sent. This provides a quick way to ensure the PTT circuit is functioning correctly, and no issues with the connection to the radio are present.
5. When connecting to the radio, only three wires are needed, PTT, Audio, and GND. There are 4 connection points on the board. The fourth (the one adjacent to the labeled PTT ) was added as a strain relief for the other 3 in heavily used situations—it is electrically isolated from all other parts of the board.
Click here for the >>>> GitHub page:
Soon there will be more detailed documentation