APRS - digital gps and heading packets over VHF; SMSGTE texting across VHF (1 Viewer)

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asutherland

VA7 HDT
Joined
Apr 23, 2010
Threads
282
Messages
3,231
Location
Kamloops, BC
Website
www.forgottenbc.ca
I took the condensed ham course a couple years ago and got my call sign: VA7 HDT basic with honours. The majority of what I've been using it for so far has been communication in the back country and on longer adventure trips with friends/family. I have a couple handhelds and a mobile Kenwood 65watt vehicle mount in the cruiser.

I recently purchased another 65 watt kenwood that will be a dedicated aprs radio using Byonics aprs equipment: Byonics - TinyTrak4 GPS Position Encoder I have the TinyTrak 4 which does 2-way communication via the kenwood and a bluetooth link to my smart phone running APRSDroid Android app: APRSdroid - APRS for Android. This allows me to do realtime tracking of the cruiser on Google Maps APRS as well as receive other aprs objects on my smart phone (I can see location and operating frequencies of nearby repeaters, for example, or other aprs equipped vehicles).

aprsmap.jpg


In addition to GPS coordinates, speed, heading, local temp, and a few other details that the APRS equipment will transmit over VHF, the APRSDroid app allows you to send/receive APRS short messages (one ham user to another) via VHF... and then in addition there's a service online run from a ham user in the states: APRS/SMS Gateway that acts as a gateway between APRS messaging and actual SMS (texts) to regular phones.

smsgte.png
SMSGTE_instructions.jpg


This means I can send and receive text messages from my phone (using APRSDroid) to/from actual cell phones. All without any cell service at all (just need VHF reception to any APRS repeater in the area). The coverage for APRS is much better than cell coverage, at least in BC.


This youtube video is an example of sending/receiving, but done via my handheld and a tablet (via an AFSK cable I made) The setup in the cruiser is much better as it's a proper radio (65 watt) and linked to my phone via bluetooth and not AFSK.



Screenshot_APRS.png
Screenshot_APRS3.png
 
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Very cool. Thanks for the write-up.

Are most ARPS digipeaters linked to the internet so that you can reach that SMS gateway from anywhere? Also, I think it's clear from your video but just to confirm, if you SMS someone they just hit reply to have their message get back to you, right? The "smsgte number" they need is contained in the message they received from you, yes?
 
Very cool. Thanks for the write-up.

Are most ARPS digipeaters linked to the internet so that you can reach that SMS gateway from anywhere? Also, I think it's clear from your video but just to confirm, if you SMS someone they just hit reply to have their message get back to you, right? The "smsgte number" they need is contained in the message they received from you, yes?

Yes, I believe most are. Transmission between aprs and aprs-is (Internet aprs portion) so far seems pretty fluid and quick.

The "association" when using SMSGTE lasts for something like a half hour, so after the initial message, both parties can just reply without using the @ portion. For cold calling, so to speak, you need to add @cell number message from aprs or @call sign if texting.
 
Goes without say, so I will anyway :)

Obviously the stuff you transmit back & forth (including cell # etc) are visible to anyone... Still a useful feature when within repeater range. You can also send an 'email' - very short one of course.

As posted before, another cheap BT connected unit that leverages aprsdroid and your smart phone. I've had one for a few years and it's a great little inexpensive unit.

Mobilinkd | Highly mobile packet radio

cheers,
george.
 
I've been using a similar setup for years. It's great on trail when you have two or more rigs setup it allows you to monitor the convoy. We have had one enabled right in lead one in the middle and one running tailgun. It has helped when we had one group split off and we were able to track their progress.

I am in the midst of building a deployable digipeter that I can put on a hill top to allow greater reliability on group trips that have a base camp.
 
@opg4759a Please keep us updated on the deployable digipeater. That's a great idea. The Byonics unit I've bought can act as a digipeater too which is neat. The main drawback so far has been getting OTHERS into it. It'd be great if it was more than just 2 of us on the trail with it.

@george_tlc Always good to mention. Yup, don't be sending any bank pin numbers across aprs! :D
 
I've got a Yaesu 8800. With a setup like this, I would presume that I have to have one of my rx frequencies set to 144.39. How does this impact my ability to tx on my "main" frequency?
 
I've got a Yaesu 8800. With a setup like this, I would presume that I have to have one of my rx frequencies set to 144.39. How does this impact my ability to tx on my "main" frequency?

Is the yaesu a dual bander? If so, there may be a way to have the aprs gear attached and functioning on just one of your frequencies. Not sure though. I ended up just buying another simple (but decent quality) kenwood for about 140$ and using it solely for running the aprs. So I have two sep vhf antennas too.
 
The biggest problem with radios Kenwood, Yeasu with APRS built is that they are very cumbersome to message on and to actually look at maps since you will have to have the correct GPS unit that will accept the data or the Geosat V which is not cheap.

An inexpensive 2 meter mobile, tinytracker 4 and Bluetooth module and a old Android phone or tablet (2013 Nexus 7 is perfect) with APRS droid with offline Open Street Maps support is a easy system to use off grid to message and map and much less expensive overall.
 
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That is a good solution too. It doesn't mean the tiny track isn't though. Different solutions for different needs. It's nice having choice. I looked at both and chose the tiny trak.
 
tt4 will run stand alone correct? So you dont always need to have your phone or tablet connected to keep it running like the mobilinkd
 
You guys are correct. Again, different solutions and options for different needs :) if I was using a hand held or needed a more portable solution, I'd prefer the mobilelinked. Or I'd make one of those neat little cables that hooks your smart phone or tablet directly to the handheld. They seem to work alright too. I wanted the tt4 because of its working independently and I wanted an external gps puck I could stick on the roof for the best reception. I also wanted to have it permanently mounted out of site in the cruiser and be able to turn the entire aprs setup on and off with a relay.

I'll take some pics once I have it fully installed :) :) :beer:
 
Yes, I agree personal preference is definitely a factor. For me, the Mobilinkd's I/O interfaces are USB and Bluetooth and the supplied Li-ion battery lasts many hours between recharges. So everything is self contained except the simple cable to my radio and I don't need a bunch of cables to connect up my Yaesu VX-170 HT. The Mobilink software is also open source, and although I've only tweaked a couple minor things in it at least I could do so. Not looking to start a fight here. :)
 
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For an HT only solution the Mobilink is a better choice since it is self contained and more portable and easier to use with a phone. I own both the Yaesu VX-8 and the Kenwood D7A and they are miserable radios to send messages on, so the Mobilink is what I use when I'm away from the rig.

For mobile the TinyTrack 4 (TT4) is a better choice since it allow some different options, linked via BT or stand alone. I have mine powered on the same line as my radio so when I flip the switch it is powered up. You can also set the TT4 to 300 baud and use it to do HF APRS on 30 meters which is what I want to tackle next.

All in all the more people that are using APRS regardless of setup off-road is great, I've been trying to get as many people on board the HAM / APRS train as I possibly can since there is so much upside.
 

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