APRS Dog Collar

[dreadlocks]

a meager 2W of VHF is not going to lead to RF burns nor lead to any more likely hood of cancer than being outside in the sun exposed to all that electromagnetic energy.. many cell phones can transmit at higher power than that and we hold em up next our face and store em next to our balls all day every day without concern..

not to mention a burst of packet radio is a fraction of a second every few mins.. so exposure time/duty cycles are extremely minimal.

I strap a 4w GMRS radio arround my son's neck from a lanyard without worry, half that power around my dog is not even a molehill to make a mountain outta.

 

[Tennmogger]

I have not seen what frequency you are planning to use. Are you talking ham radio frequencies? Look up PicoAPRS on this site for tech info: http://www.db1nto.de/index_en.html, and drop down to the spectrum analyzer scan. It is obvious that Pico APRS is on 144.8 MHz, certainly a ham frequency. Looks to me like the originator intended the device to be onboard a ham op.

I am no expert but is it legal for non-hams, ie, dogs and cats, cars and trucks, to be running around transmitting in the ham bands? Don't think so. Of course it's legal for a ham radio operator to have a remote transmitter but it has to identify itself, and must be directly under the control of a licensed ham who can turn the transmitter off in case of problems.

Someone enlighten me.

 

[dreadlocks]

the dog is not transmitting or operating the radio, and the nature of APRS is it is identifying its self with every packet it sends.. remote stations dont have to always be under direct control either.. we've got a whole network of mountain top repeaters that be completely inaccessible physically at certain parts of the year.. I've got a 2-way iGate running at my house, its been receiving/transmitting for a year now unattended.. even when I'm not at home, or capable of remotely managing it.

I think the idea is the dog/radio will nominally be in full control of the operator, if the dog runs off or gets lost and the transmitter goes haywire.. well you could easily argue that life/property is in danger and then nobody listening is going to be concerned about rule violations in such a situation.. also keep in mind these are rules, not laws.. breaking rules does not mean your illegal, and the only ones whom enforce/police the rules are other ham operators.. FCC is largely toothless and struggles to get actual pirate stations off the air.

PS: a standard APRS beacon is a dog icon, so clearly hams have endorsed this use. https://www.aprsdirect.com/symbol/usage/code/112/table/47

 

[DaveInDenver]

The FCC allows stations where physical access is inconvenient, like beacon station (not APRS position packets, actual beacon stations), repeaters and remote stations (such as those on a weather balloon or weather stations) to be indirectly controlled, which means you either have a way to shut the transmitter off using a second frequency as a control channel or they have the ability to shut themselves off automatically, like a time out or re-key timer.

Hams usually cite this as justification for trackers they place on pets, cars or hand out to non-hams. The intent of the law is to take control of an errant station if it's causing issues. In the backcountry it may be unlikely you would interfere with other station or need to turn off a radio as required (like going near a mine or construction site utilizing explosives). There is no exception for having no control if you can't access the transmitter.

I know the point is to find a lost dog, but if he wanders into a place where it would be an issue or it falls off it should probably have a way to shut it down.

Pico APRS is on 144.8 MHz, certainly a ham frequency..

By convention U.S. amateur APRS is done on 144.390 with some exceptions. It's done on various frequencies elsewhere so if the PicoAPRS is defaulting to 144.800 (being German I assume it is) it'll need to be moved most likely.

• 144.390 MHz — Colombia, Chile, Indonesia, Malaysia, North America, Thailand
• 144.575 MHz — New Zealand[5][6]
• 144.640 MHz — Taiwan
• 144.660 MHz — Japan
• 144.800 MHz — South Africa, Europe,[7] Russia
• 144.930 MHz — Argentina, Uruguay
• 145.175 MHz — Australia
• 145.570 MHz — Brazil
• 145.825 MHz — International Space Station[8]

Probably should use a non-standard frequency though since having dog trackers showing up on 144.390 and APRS-IS is probably inconsiderate. I also think 144.800 is a repeater input (for 145.400) many places.

 

[Airmapper]

Probably should use a non-standard frequency though since having dog trackers showing up on 144.390 and APRS-IS is probably inconsiderate. I also think 144.800 is a repeater input (for 145.400) many places.

Perhaps, but also consider for someone surfing aprs.fi or over the air signals, it might be the most interesting activity you see in a year.

I know I get a kick out of seeing some unique activity on there. I've actually seen dog tracking on there and watched it for a while thinking it was cool. You find some neat stuff when folks inject their tracking into the public frequency, like balloon chases, and I'm especially fond of seeing station WW2LST's position updates.

By and large, APRS is so underused in many areas any time someone takes advantage of it and it's visible on 144.39 I'd call it a win. Ham's are getting so stuck in the mud and afraid to use it that if anything it's become the sole realm of those who talk for long periods of time and in depth about health problems. I've never seen a group so concerned about hogging frequencies that almost nobody actually uses. It's been months since I turned my mobile on to scan local repeaters and heard a single soul. 2M is dead here, and I'm not sure 70cm was ever alive. Finding anyone who knows enough about APRS to even use it is a rare gem.

I'd hope anyone sharp enough to set up dog tracking APRS is likely bright enough to know if the local infrastructure will be unduly burdened by it. After all anyone with a mobile station passing nearby is likely going to stomp on a collar transmitted packet and get out anyway. I'd be mindful of the path, don't have it repeat unduly past the nearest Digipeater. In my case with a D710 I can set a HT to only repeat through my my mobile in the first place. You can probably rig a path so it only gets to a nearby i-Gate. That said people who do APRS sometimes don't seem to know how to set any of it up properly, but it is so barren of activity, they hardly bother anyone.

 

[DaveInDenver]

@Airmapper, all valid points. I reckon that the point is to use amateur radio to tinker. So maybe like two hams tying up a repeater rag chewing about ailments consider it's shared use so maybe limiting hops to keep it just locally retransmitted or vice-versa, just routed to the APRS-IS. With the expanding use of Internet linked radios seeing someone walking their dog with an APRS beacon, you could theoretically chat with them across the country. It would be interesting to try.

Maybe what I'm struggling to say is to think if it's something other hams will find useful and interesting and adjust appropriately. There's a ham here that has an APRS station on his plane, which is pretty cool to watch. My point is that regardless of necessity you do need to be able to control your transmitter, so dog trackers to me fall into a gray area. Since it will beacon it's location I guess it's not like you can't recover it if it falls off.

In any case, broadly speaking, I personally don't really care for blind APRS position transmissions either. If you're going to beacon your location at least monitor for voice. We're not broadcasters. I have a handful of friends who run automatic beacons and in my old radio (FTM-350) when their call sign was heard I had an alarm set and I would make a call so we could chat.

 

[dreadlocks]

APRS transmitters have alot of failsafes that allow it to be ran unattended like remote stations (time out timers, watchdogs, self monitoring), plus they listen for a period of silence and then broadcast a quick burst of data thats no more than a second or two every min or two, very low duty and tries to play fair with its neighbors.. any portable device are low power and battery limited, so even if ur dog falls off a mountain and is never seen again.. its not like that transmitter can even operate for more than a day or so after that.

We are self governing and rules are for us to enforce, and we are generally very nice people.. I repeat dog tracking devices from time to time and am elated to see its use.. If someone has a malfunctioning or bad device we go find em and help em fix it.. we dont just send FCC out to fine them and confiscate their gear unless they are a persistent troll whom ignored all attempts at reason.. Rules are great and all, I'm all for them but dont let em hold you back.. historically the grey areas of the rules are the ones that lead to cool new uses for the technology, there was resistance at first to digital use because many saw it as obfuscation/encryption of sorts because their ears could not decode it..

APRS is one of the coolest things we ham's got going, I dont like talking to people.. im here for digital radio, if it was just a bunch of old farts rag chewing and gatekeeping with morse paddles then it'd be a dead hobby with no future...

 

[DaveInDenver]

The only resistance to digital was DMR and that's because the FCC didn't recognize the emission type as legal for amateur radio. We were still using it but since your call sign isn't encoded in the bitstream a monitoring station couldn't know who is transmitting and people were relying on the D-MARC contact database for ID.

D-STAR and Fusion were both fine (type 9K36F7W) from the get-go because they define a location for your call in the protocol, like APRS does. It doesn't matter now, the FCC recognizes 7K60FXE and 7K60FXD as legitimate for amateur use as long as you announce your call sign like you would with an analog emission. With Talker Alias maybe the reliance on the database will start to fade, although none of my radios can actually support it yet.

Hams have been complaining about different modulation types since spark gap was overtaken by CW and AM. So that sort of resistance is inevitable I suppose.

I happen to 100% agree about APRS, especially for off highway use. So much potential, so little application and understanding.

As far as APRS transmitter failsafes, I think you assume a bit much. Most beacon controllers are broadcasters that don't even listen for their own call sign for packet skipping, much do anything semi intelligent in the event of actual interference. The Mobilink is hugely popular and doesn't do 90% of even what a PicoAPRS, Tinytrak or similar KISS TNC does. Much less a full TNC implementation. The TOT would be dependent on the radio mostly other than maybe a stuck PTT circuit monitor, which I don't think anything short of a Kantronics would have, if even they do that.

 

[dreadlocks]

yeah im not saying all APRS trackers are infallible but many have reasonable safety features, some tho are rather stupid.. but many are good enough for most uses, people launch High Altitude Balloons all the time with transmitters they will never see again, let alone be guaranteed full control over it as it broadcasts across half the continent due to its amazing line of sight capabilities.. yet were arguing about putting em on a dog thats likely trained to respond to commands and return home because of some arcane rules that depends on interpretation and context of the original purpose.

there is no reason an aprs tracker cant be designed to be remotely controlled entirely, the problem is security.. if someone else hijacks it because encryption cant be used then its a bigger problem than one operating standalone off pre-determined behavior.

In the end it comes down to testing, dont let your transmitter out of your control until you have tested/validated and can launch your unmanned tracker with some confidence it will behave its self.. but if something does go wrong, you might have to explain your self.. and if your explanation comes down to, I just prayed it would work right before I let it out of my control then you'll be standing on a rather poor footing.

 

[DaveInDenver]

resistance at first to digital use because many saw it as obfuscation/encryption of sorts because their ears could not decode it.

BTW, I forgot to make a point. Using digital or anything else does require being nice to other. There is nothing illegal about using the spectrum however the heck you want as an individual. The FCC just wants you to stay below 1,500 watts and within the edges of the allocations. Everything else is by shared convention via ARRL and local (usually state-wide) coordination with band plans. So using a digital mode on established FM simplex channels means you should monitor for other users first and perhaps announce with FM that you intend to use digital. Repeaters are obviously up to the owner, so that's not necessary. But it's like guys using high power within QRP or astronomy designated frequencies, it's sometimes that we can be rude to each other.

 

[DaveInDenver]

ydog thats likely trained to respond to commands and return home because of some arcane rules that depends on interpretation and context of the original purpose

LOL, the reason I'd want to have a tracker on my pup was mainly because he wasn't all that good off leash. Being a malamute/GSD mutt he was hard headed and easily distracted. Look! Squirrel! <BOOM> Gone. Sometimes he would get so focused that he wouldn't hear or listen until he realized he was out of sight and would start to panic. If he was a better behaved (and, yeah, trained) I doubt I'd have needed it on him. Mostly he stayed on leash, though.

I know hunters like to use trackers for their dogs even though they are usually well trained.

This does remind me of another argument within backcountry skiing circles. Some people would put avalanche beacons on their dogs. That is something I never did for mine, though. I understand wanting to find him if he was buried but that did put people at risk if they were buried and you were chasing a dog's beeper because he didn't know to change it to listen. I never have personally had to effect a burial rescue but I've heard anecdotes of rescuers getting confused momentarily following a dog taking a leak. It's always "But my dog is good." True, until it's not.

 

[dreadlocks]

analogue tracking beacons traditionally used for animal/wildlife tracking tend to be alot less friendly to anything else operating on the frequency.. since they are effectively just a tone generator with no logic.. at least an aprs equipped pupper is just sending a short burst with its exact location instead of a constant homing signal yeh gotta foxhunt..

if anything using a digital aprs tracker would be more friendly to nearby emissions than an old analogue system..

I got a cell phone based tracker for one of my cats that kept disappearing for weeks a time, he ended up loosing it and we could not find it before batteries died so its gone now.. but for several months we tracked him and figured out his stomping grounds, where he hangs out at.. and now if he dont come home we go to those areas and call for him and he comes right home.. so dont really need the tracker anymore.

 

[DaveInDenver]

APRS is AFSK (technically emission 11K2F2D), so the potential for interference is dependent on the signal level you inject and the ability of the radio's gain control and filtering to deal with it. The information being digital does have fairly sharp edges, so if the TNC is overdriving the envelope is going full of harmonics and will force the RF amp to go non-linear very easily. Need to think about how to bypass the mic pre-amp (which may or may not be the case if you the "data" jack) or at least realize you need to be careful setting levels.

 

[Hillbilly Heaven]

Is there a dog symbol for APRS and can Identifier be letters and numbers like K4IBC-K9

 

[dreadlocks]

https://www.aprsdirect.com/symbol/usage/code/112/table/47

/p = rover

SSID's should be 0-15 if you want to ensure your packets are routed properly, -12 would likely be most appropriate for this use as it indicates just a transmitter and no receiving capability..

Path should be WIDE1-1 for this, or if you'd like to ensure no repeating, gating or routing use the call sign of your receiving unit and anyone whom hears it will simply ignore it and your receiver will see it as a direct packet to it..