Packet Mobile APRS packet repeater / Tracking

[GriffinJax]

New Ham here, Just passed my Tech license exam.
I want to build an APRS mobile tracker with message, but was thinking I might as well build it as a mobile packet repeater also.
I have a Camp, that is "Off Grid" (no cell coverage or power) and spend a lot of time there in the spring, summer and fall.

I have an Motorola Maxtrac and was looking at getting an OpenTracker and Ads-sr1 repeater to put in my truck, Ill pull the GPS signal from the factory ford GPS antenna and I am still deciding on antenna setup. I think I can run the Maxtrac at a 25watt minimum.... still looking into that.
The whole setup will be on only when the truck is running.

The question, is a mobile packet repeater a good idea or not.

 

[jeepsandradios]

So what your wanting to build is a digi-peater. Mobile Digi is not normally a thing. Also you cannot pull GPS from your factory antenna will need another antenna. Your best bet is to grab a TinyTrak 3 and GPS to hook to the Maxtrac. I have run many that way. That should still TX regardless of your location. The TT4 allowed Digi operation but is OOS at this time.

 

[BMDaug]

I run a man pack radio with a Panasonic toughpad (Windows 10) that will fill-in digipeat when on the go… it’s normally not in this mode, but the mountains prevent handhelds from reaching the igate in some areas and it’s handy to digipeat (one hop only) with 35 watts. My setup will also igate when I’m in cellular service (touchpad has a SIM card). It is a bit unusual to mobile digipeat, but it just depends where your nearest igate is and whether or not a handheld can make it or not. If it can’t, a one hop digi can definitely help.

-B

 

[GriffinJax]

So what your wanting to build is a digi-peater. Mobile Digi is not normally a thing. Also you cannot pull GPS from your factory antenna will need another antenna. Your best bet is to grab a TinyTrak 3 and GPS to hook to the Maxtrac. I have run many that way. That should still TX regardless of your location. The TT4 allowed Digi operation but is OOS at this time.

I meant an actual RF packet repeater.
I could do a digi-peater around where I live and work.
I am going to do another APRS setup at home at some point over the winter.

But the routes I travel and where I spend time at my Camp. There is no cell service. No power except a generator.
I was thinking a Mobil repeater / tracker would be fun. But I’m taking it that the repeater maybe frowned upon.
I should have mentioned I live in Maine, we still (Thankfully) have areas that aren’t cover by any cell coverage.
Thank you all for your replies.

 

[BMDaug]

I meant an actual RF packet repeater.
I could do a digi-peater around where I live and work.
I am going to do another APRS setup at home at some point over the winter.

But the routes I travel and where I spend time at my Camp. There is no cell service. No power except a generator.
I was thinking a Mobil repeater / tracker would be fun. But I’m taking it that the repeater maybe frowned upon.
I should have mentioned I live in Maine, we still (Thankfully) have areas that aren’t cover by any cell coverage.
Thank you all for your replies.

So that is a digipeater… RF in and RF out. An igate is an internet gate that passes packets to the APRS-IS network. Digipeaters are very common to relay weak signals to an igate that is too far for an HT or other low power transmitter to reach. They just are usually in a fixed location, not mobile.

As long as you set it up right, a fill-in digipeater can be useful, but you can’t just repeat every packet received. APRS packets contain information about how many times, if any, they have been digipeated. You would need to set up your digipeater such that only ‘original’ packets are repeated because you may otherwise be repeating packets that are already being repeated by other digis or packets that are coming from a bidirectional igate. This potentially ties up the APRS frequency with lots of traffic and can cause duplicate reports to reach the servers.

Also, remember that a digipeater is a sort of ‘buffered simplex repeater’ where it will transmit on the same frequency as it received on. It hears an APRS packet, decodes it, checks to see how many times it has been digipeated or if it came from an igate, then follows a set of rules you define in your digipeater and decides whether or not to transmit the packet onward.

Hope this helps!!

-B

 

[GriffinJax]

That helps a ton actually.

I’ve done a lot of reading on APRS, but the documentation is quite spread out.
I’m still learning.
I’ll update this Thread with my setup as things come together.
Thank you for the Clarification.

 

[K5MPH]

If you dont have internet at your camp you will need to Igate to some one that does if you set up a fill in digi it will need to igate in to another igate that is connected to the internet and also at your camp site how far are you from a Igate.......

 

[BMDaug]

He could fill-in digipeat to another closer digipeater, which can reach an igate.
In his scenario, he wouldn’t igate at all, just digipeat either directly to an igate if one is in reach, or to another digipeater, which could reach an igate. If he doesn’t have any internet connectivity, he’s not igating, that’s for sure!

That’s how it works in the mountains around here… even though, as the crow flies I’m pretty close to an igate, it’s over a ridge which frequently deafens it from hearing my location. I end up hitting a digipeater which is higher but actually further from the igate on the other side of the valley, and that reaches the igate just fine!

Just remember that a digipeater is strictly RF in/out. An igate is RF in and internet out, and a bidirectional igate is RF in, internet out AND internet in, RF out so that other non internet connected nodes can receive positional data from the APRS-IS system.

-B

 

[GriffinJax]

So it appears from looking on aprs.fi that the closest digi is 7~ miles or so from me. the next closest is around 25~ miles to the north west of me.
West / North west of me is high ground, multiple ridges and valleys in that direction. The digi 7~ miles or so from me is south east and I have a clear view of that direction. That digi is shows a good path to an Igate/digi about 42~ miles away.

Also, still waiting for my call sign to show in FCC so I'm still waiting to be legal before I go much farther, but I'm testing for General on Friday. Wish me luck.

 

[BMDaug]

So it appears from looking on aprs.fi that the closest digi is 7~ miles or so from me. the next closest is around 25~ miles to the north west of me.
West / North west of me is high ground, multiple ridges and valleys in that direction. The digi 7~ miles or so from me is south east and I have a clear view of that direction. That digi is shows a good path to an Igate/digi about 42~ miles away.

Also, still waiting for my call sign to show in FCC so I'm still waiting to be legal before I go much farther, but I'm testing for General on Friday. Wish me luck.

If you have a clear view to a digi seven miles away that is known to consistently hit an igate, then you may not need a fill-in digi at all! You can probably just hit the digi with your radio and that will make it to the igate. You could still build a fill-in, just to experiment and better understand how APRS works, or if camp is closer to and has a better view of the digi than the area you will be roaming around in. Like if your camp is at the end of a canyon that you will frequently be hiking/hunting/whatever in and you know your view of the digi will be obstructed during those activities.

Good luck on your test! General is IMO the most functional license. I might test for extra in October but I just haven’t had much time to study so we will see! Just keep up the studying and you’ll do fine!

Have a great day,
Brian

 

[K5MPH]

Like BMDaug said you could just use a APRS Tracker being you are only 7 miles away if that dont work then put up a fill in Digi and if you go that way it might help other hams in and around the area also,anyway good luck on your test by the way this is what ham radio is all about and good luck on your APRS project.......