Aprs

I recently added winlink back to my APRS ping on the UV-PRO. I immediately got a message from a Winlink gateway that I had 1 new Winlink message waiting. For the full RF experience, I fired up KISS on the UV-PRO and a session to K3IR’s Winlink gateway (145.030kHz) and checked my Winlink mail over the radio.

I needed to be careful to not let HT app start and re-enable “digital mode”. When “digital mode” is enabled, it would switch to APRS 144.390MHz every time WoAD would TX, and that doesn’t work. The hint was seeing APRS traffic in the WoAD log while waiting for my Winlink session to initialize.

The email was KC3WRY, Matthew, playing around sending Winlink via APRS. I acknowledged and responded to his message.

I caught word that ISS was passing in a moment, so I tuned UV-PRO to 145.825MHz, the APRS digipeater on ISS. I heard packets from Pittsburgh, PA; Smyrna, DE, and Atlanta, GA. I tried to ping out my location a couple times, but it looked unheard according to https://ariss.net/.

The HT app and UV-PRO digipeats APRS packets like a mesh.

Watching traffic, I discovered one can ask the REPEAT service on APRS to list repeaters near you.

Yet Another Radio

I got interested in AX.25 packet over RF, so the Btech UV-Pro immediately looked like an interesting jumpstart, when it got a firmware update that allowed it to operate as a KISS TNC over Bluetooth.

Application Driven

HT is the up-to-date app for interfacing with the radio. There’s a “BTech Programmer” app, but it is an older, branded version of HT.

Setup

In the radio, I’d set “General” -> “Digital” -> “Format” = “APRS”, but the HT app kept switching it back to “BSS” any time it connected to the radio. It would never let me set “APRS” until I “verified” my ham radio callsign. It wants to do it by sending your license info to some chinese site – no thanks. Instead, I used a web app to generated an APRS code that worked in the HT app.

I enabling digital mode in radio to make it periodically beacon my APRS location. I set it to a fixed channel for sending APRS. Only the HT app seems to be able to set the beacon text for APRS.

I can send messages from radio by prefixing the message with the recipient:

KC3WWC-7: hey

TNC KISS Mode

I installed WoAD on Android, and enabled TNC KISS on the radio. I paired the radio to the phone via Bluetooth. I checked the Winlink RMS map on the website to find nearby packet gateways, and set the radio to the given packet frequency for the gateway I was trying to use. I configured a session for the callsign and SSID of the Winlink gateway, and started the session. Now it’ll send and receive queued email. There’s a log in WoAD that shows what it’s doing.

WoAD also has a terminal which can be used for BBSes, like KA3TKW. I connected there to see some messages and a BBS software from 1990!

APRSDroid can also talk to KISS TNC over Bluetooth. It’s a much nicer UI than the radio or HT app. Sometimes when switching apps, I needed to cycle power on the radio, but it doesn’t usually take too much to get it going again.

Direwolf doesn’t want to do anything without a local config in place. I had to decompressed /usr/share/doc/direwolf/conf/direwolf.conf.gz to $HOME/direwolf.conf. I customized the configuration file:

• set my callsign
• listed audio devices with arecord -L, found pipewire, and set ADEVICE pipewire in the config
• plugged the Btech APRS cable into the Quansheng and computer
• Direwolf is decoding packet (from 145.010MHz) and APRS (144.390MHz).
• -q d quiets APRS decode errors when reading plain packet
• -t 0 disables the colors
• with pipewire, I can have both my record-aprs.sh script and Direwolf decoding.
• decoded APRS from ISS on 144.825MHz via multimon-ng:

AFSK1200: fm KB9VIC-9 to DH4TLZ-0 via RS0ISS-0,WIDE2-1 UIv pid=F0
`t].l .#\`KB9VIC EM58 OLNEY IL HOME OF WHITE SQUIRRELS _%
AFSK1200: fm KA2OMQ-0 to W4BB-0 via RS0ISS-0 UI^ pid=F0
QSL? UR 59 FN13
AFSK1200: fm W4BB-0 to CQ-0 via RS0ISS-0 UI^ pid=F0
:KA2OMQ   :QSL and 73 via ISS
AFSK1200: fm W9QO-0 to STPX1V-0 via RS0ISS-0,SGATE-0,WIDE2-2 UIv pid=F0
'oIPl .-/]

The Working Configuration

I’ve gotten APRS working with my current gear. I’m running my UV-K5 running egzumer 0.22.0 and VOX enabled. I set the radio volume pretty high, about 75%, and connected the BTech APRS cable and a USB-C 3.5mm audio adapter to my Pixel 6 Pro for an audio connection. The volume on the phone was set to nearly 100% volume. I ran APRSDroid in AFSK mode on the phone.

I watched for my position to show up on the map on https://aprs.fi/.

The Stuff That Didn’t Work

With nunu firmware, I needed to key it manually, but it worked. VOX didn’t work in the nunu 0.20.5, so I switch back to egzumer for working VOX.

Next Steps

I’ll next try to find an old phone to run the APRSDroid and try to use the Explorer QRZ-1, so I can dedicate some hardware to this project.