APRS Dog Collar

[DaveInDenver]

SSID -12 makes the most sense but -1, -2, -3, -4 and -15 are generic and would work, too. Some of the others by convention have specific meanings so using them on a tracker would potentially be confusing.

BTW, @Hillbilly Heaven, -K9 won't decode correctly. AX.25 only has a 4-bit SSID field thus is limited to 0 through 15. There is a method to get around this by defining "K9" as an object rather than a station. SSID for an object isn't constrained to a 4-bit field rather it's 9-bits. Routing and digipeating of an object isn't uniform, though, so like @dreadlocks says it might be confusing using a unusual approach like that.

 

[Hillbilly Heaven]

Thanks I wasn't aware of the /p and yes -12 with wide1-1 sounds best. Sometimes rover might be to far away to hear direct but digipeater might hear it.

 

[Pacific Northwest yetti]

Just curious did you do this, and how did it work?

 

[worthingtontw]

Just curious did you do this, and how did it work?

I played with it a bit. Just got back from a Death Valley trip today where I tested it out and results were mediocre but this was more of a proof of concept. I took apart a Baofeng uv5r to slim it up and remote mount a battery and made a cable to connect to an old android phone running APRSdroid all attached to a molle paneled harness. As far as the stated goal it worked very well, however it ended up being very bulky for hiking. Did help though when she went all adventure puppy and left camp when we weren't paying attention during dinner.

What I learned from all this was that you need a fair bit of gear and patch cables on both ends unless you want to buy something like a Pico-APRS for the dog side (saw the prices are now down to $200 so I may still do that). You are still left with a less than optimal solution on the user end though as you at minimum are carrying a bluetooth tnc/radio and a phone. We did prove a 3 mile range though with a SRH-805 antenna on 4 watts which way outperforms off the shelf stuff, but reality set in when she went exploring and the geofence alert/page features would have been nice to have. If you are looking for a radio project, its fun to play with as it is far from the standard use case for HAM. Having said that, while it was fun to play with and work through the problems on a $50 project budget we are now saving for a Garmin system because it just works and its less crap to keep in my pockets around camp and on the trail.

 

[Pacific Northwest yetti]

I used to run livestock, and had Great Pyrenees livestock guard dogs, they are amazing protectors for whatever they deem is their family/pack. With the sheep, they were opened up to a large open range pasture ( 1k acres + ) but a single water point down by the barn and house, a lot of they guys I knew were trying to find ways to track the dogs, as a way to track the livestock as well. Great Pyrs also do a fair bit of wandering in their work day, there was never really a great system for this when we were looking.

I am spending a few years w/o livestock now and only have 1 pyr left, but will start raising them again at some point. And always looking at options,


thank you for the reply.

 

[sonoronos]

Maybe one alternative is to get away from using the Bell 202 AFSK AX25 implementation, which is sort of implied with APRS.

The total amount of bits required to track dogs is very small - it could probably be reduced to a message under 64 bits with sufficient location precision, which could then be compressed and convolutionally coded. Then the data rate could be reduced and FEC used to increase range.

I think there are some consumer technologies in the ISM bands (like 500mW or 1W LORA units "Long Distance" units) have more liberal spectrum usage and can take advantage of coding gain in this way. The protocols also negotiate traffic. Because these units typically have straightforward serial implementations, probably an arduino plus gps module could be rigged up in a single board.

A good receive antenna with appropriate filtering and LNA could further increase range.