I started this project thinking that it’d give me something to finally make a long post about, however I guess I was able to sum it up in a couple of Tweets and Facebook posts… But I’ll explain it anyways. The initial plan was to use a Raspberry Pi, and USB-SDR dongle, a Baofeng HT with a VOX interface cable, two antennas, and a piece of software called DireWolf. If you’ve never head of DireWolf, it’s essentially the backend for a digipeter and iGate, software that’ll trigger the PTT on the radio in some method – whether you’re using a serial USB interface that needs an actual command to transmit, or something that just generates a sound to transmit and triggers the PTT through an external sound card such as a Signalink or DigiRig, or through the VOX interface like I am.
The reason I explain above as my ‘initial plan’ is that I was having some issues with the file directory hosts for some of the sound card drivers that had to be downloaded. I would launch DireWolf on the Pi, but it would not provide me any of the drivers – in fact it was acting as if there were none at all. So as a plan B, I loaded it on to my desktop – I’ve turned off all system sounds so nothing is going to transmit (a problem all too often seen on the air waves when people are using FT8 through their Signalink devices), so the only audio going out should be that of the received APRS beacon.
On Windows, this took about 30 mins to configure GPS locations, register with the APRS gateway, set the sound card parameters, and decide ontransmit intervals for the location of the digipeter. It turned out that there’s a TX delay feature so you only need to use one radio for both TX/RX, so I’m returning the USB-SDR dongle, which was the most expensive part of this whole project (at $35 after tax), kind of funny given that I purchased a new radio even to run this off of. I’ll line item the costs out below for building this. It was a fun project that I thought may take a little more time, but it’s cool to see how little you need to make something like this work. It’s all about the software in this case. If you’re in the Batavia area, please reach out to my call at outlook.com with a report as to where you tried beaconing from, and if it worked for you! My QTH isn’t in the greatest spot for RF activity, but it’s nice that we now have some type of coverage in our area!
Costs:
Baofeng UV-5R8W Kit: $25.97
Reverse SMA Adapters: $6.58
BTech APRS-K1 Cable: $22.49
USB Chargeable Baofeng Battery (optional, but reduces noise): $17.62
All in cost: $72.66 using an existing PC and antenna… not too shabby! Hopefully will make incremental upgrades to this little project, and will be moving it over to a dedicated little MicroPC that I garbage rescued from someone taking to eWaste a few years ago. I was initially going to make it a Rover PC, but I think that this is the perfect use case for it!
Roving On 