I have recently discovered a gap in APRS coverage in an area I frequent.  After some thought, I realized that I may be able to fill this gap with a digipeater (or possibly an I-gate) of my own.

Some considerations:
1.  It's 45 minutes away from me and would need to be "hands off"
2.  Let's pretend there is no infrastructure at this location.

With that said, I've read up on people who have built "digipeater in a box" units using solar power, so that's pretty well documented.  However, I haven't found anyone using cellular data to make an I-gate.  I could just turn it into a plain old digipeater, but IMO an I-gate would be useful, so let's stick to that as a goal.

Has anyone here ever set up something like this before?

Bonus question - it seems there is quite a bit of controversy regarding whether or not adding to the APRS infrastructure is a good idea, but with seemingly little objective guidance.  And by that I mean the stuff you read such as "You can set up a receive only I-gate no problem" vs "all of these receive only I-gates are breaking APRS" and "before you set up a digipeater you need to make sure it's not going to interfere with everything else" ok, how?  by checking with the nonexistent digipeater coordinating body?  Some of these warnings strike me as having a bit of the usual "everyone else is WRONG" undertones so often found in this community, but I'm here to learn.

If you legitimately have a gap in coverage and there aren't other digipeaters all around you, then putting in a little fill-in digipeater should not be a problem.

I have a "Wide1" fill in digipeater to provide some coverage in my area.

If your digipeater can be heard by an igate, then you don't really need to igate and I wouldn't worry about that.

It's important to know how the routing codes (wide1/wide2) work, and how to set up a digipeater correctly to avoid conflicts. Most of the time a small area-fill digipeater should be on wide1 only, and that shouldn't cause problems unless you have significant frequency congestion.

Kenwood instruction manuals have some great APRS content.  And kenwood radios such as the D710 and some of their handhelds can be fill in digipeaters out of the box.


https://manual.kenwood.com/files/TM-D710G_CD-ROM_English.pdf


And don’t forget to read the spec itself:

http://www.aprs.org/doc/APRS101.PDF

The Microsat PLX digi is pretty much set it up and forget about it.  Pretty good stuff.
I'd rather do that and a $50 hamfest vhf rig than leave a 710 in the wild somewhere.

Microsat PLX Digi

That's what I'm not sure about.  I really need to do some actual testing, but based on local knowledge and screwing around with a handheld, I'm not sure that's going to be easy (25 mile trip, with the I-gate antenna at 80').  I'm also not constructing a tower or anything like that, more like coax colinear strung up in a tree.

One thing I'm curious about is the average data consumption of an I-gate.  I'm sure this varies wildly, but it would be good to know some base figures.  Some of the cheaper hotspots (example: $10/month for 2gb) I wouldn't think twice about, but $50/month, ehh not worth it.

If you have to go out of your way to put in an internet connection, then it doesn’t need tk iGate.


The whole point of APRS is it doesn’t require the World Wide Web. You could - given proper setup - send a message from one side of the country to another through digipeaters.


In practice it doesn’t work that way. But surely your digipeater is with two hops of an igate…

This ^^^^^

Great article on understanding the path system built into APRS.

http://wa8lmf.net/DigiPaths/


For reference, almost every modern APRS radio such as the d710, Yaesu FT3dr, etc has the following path pre-specified. Your fill in digipeater will pick it up, then retransmit, from there it will digipeat two more times and then expire.

Wide1-1,Wide2-2

Strongly recommend downloading direw0lf and setting up a low powered digipeater (like 1 watt) to play with and see how it all works. (Especially filtering) I use a signalink and yaesu VX-6.  But baofeng radios work too. You’ll want an APRS capable handheld to simulate the mobile “user” station.

I would first verify that your current setup was not the issue, are you using an external antenna, what was your power output, and what was is your APRS path set to?

Can you secure this area that you want to deploy from theft and vandalism?

I like the Microsat devices. The WX3in1 Plus 2.0 is what I use for an Igate. It works really well with the Yeasu FT-2980R

I have used cellular as a backup when my home internet has gone down.

My setup

Yaesu FT-2980 $180.00
Microsat WX3IN1 Plus 2.0 $140.00
CAB30B cable $8.00
X50 Diamond antenna $120.00
GL-Inet GL-AR300M $30.00 used as an Ethernet bridge to wireless to the cell hotspot.

You can use any radio that has a cable option prebuilt or make one.

I would not worry about interfering, unless you are over broadcasting or have a path set to high. I have my Igate set to update its status over the air every 30 minuts, and TCP every 15. The stations I find annoying are weather stations that send weather updates every 15 seconds.

I appreciate everyone supplying links and info.  Thinking about this has prompted me to learn a lot more about APRS than I ever thought I would.  Oddly enough, when I was first licensed I thought APRS was kinda dumb, to be honest.  Then, a couple of years ago I bought an FT2D mainly just to say I had C4FM capability, not even knowing or caring it was APRS capable...

A point of clarification - I said the nearest I-Gate was 25 miles away, but I should have said that the nearest digipeater is about 25 miles away.  Testing so far has been on the handheld with 5 watts, so not an ideal setup; but another thing to note is that there is no traffic on 144.390, so not only am I not hitting any digipeaters, I'm not receiving any, either.  Thus why I'm wondering if my proposed setup would be able to get "out" or if I'm creating an island, so to speak.  I think the only way to know the truth here is to try a mock up to see what my proposed setup would be capable of.  

Believe it or not I have gotten some of my best results from a 1 watt PLXTracker TRX1W from Microsat. In order of best results to least.

PLXTracker TRX1W with APRS droid
5 watt radio with tnc3 APRS droid
Yeseu FT3dr
Anytone 878

I run my igate from my home, it gets good range, but I also have multiple mountain top digipeaters that I receive traffic from.