APRS the easy way

[Mudderoy]

I've always found APRS interesting. It's a way not only to get your position on the planet but report it to others, and do so without using the Internet.

Yes your phone can do this now, easily, but much of the ease is because a multi-billion dollar infrastructure, the cellular phone system, and a multi-trillion dollar system GPS satellites.

In APRS we only make use of the satellites. :D

Amateur Radio really was the forerunner to the cellular network since really your phone is just a transceiver that sends and receives signals to a repeater. That repeater boosts the signal to other transceivers or patches them to other services, like land line phones.

I purchased a Mobilinkd TNC2 a few years ago. (http://www.mobilinkd.com/)
https://cdn.shopify.com/s/files/1/0243/0845/products/IMG_20170405_205156_1024x1024.jpg

This is literally all you need to do APRS
https://cdn.shopify.com/s/files/1/0243/0845/files/APRSMadeSimpleSM_grande.jpg

A smart phone, this TNC and a inexpensive 2 meter handheld radio.

The TNC plugs into the radio, and the TNC connects to the smart phone via bluetooth. The smart phone provides GPS information and the software to send position data and text messages to the TNC.

This information is broadcast out on 144.390 Mhz. Someone actually made a really nice online map...

https://aprs.fi

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I clicked on one of the home based weather stations. What does weather have to do with APRS? That's just it. APRS reports position and other information. The "other" is like a fill in the blank.

In addition to the TNC listed above you will need
APRSdroid for your Android phone

What?!?!? No Apple support?!?!? Not with this TNC...

What about Us iPhone Users?


We really wish the Mobilinkd TNC would work with the iPhone, but iOS lacks support for Bluetooth Serial Port Protocol (SPP). Until that changes, it is not possible to use this TNC with an iPhone or iPad.

[bluedragon436]

Does the cell phone you use have to have service, or just work & have GPS & bluetooth?? I've got a few old smart phones that I could do something like this with, but they are no longer in service, so was just wondering if I could use one of them for this, or would I have to put it back on my Verizon account to make use of it?

[Mudderoy]

It does not! Well logically it shouldn't but I never tried it. I was hoping to use my old GII for just this purpose, but the power off/on switch needs to be replaced. I decided to try a touch screen on my Pi and it just rolled into APRS project.

But an old cell phone, or perhaps a cheap one from ebay that has been disabled for use by any carrier would be a cheap way. You'd need the phone, blue tooth and GPS enabled, a radio and a TNC. Oh and the APRSDroid software which you'd install by copying it, or using WiFi to access the Google Play store.


Does the cell phone you use have to have service, or just work & have GPS & bluetooth?? I've got a few old smart phones that I could do something like this with, but they are no longer in service, so was just wondering if I could use one of them for this, or would I have to put it back on my Verizon account to make use of it?

[4.3LXJ]

Uh Tony, this is above my pay grade but it sounds like this is not the easy way. On top of that I am not sure what you are trying to accomplish here

[prerunner1982]

Does the cell phone you use have to have service, or just work & have GPS & bluetooth?? I've got a few old smart phones that I could do something like this with, but they are no longer in service, so was just wondering if I could use one of them for this, or would I have to put it back on my Verizon account to make use of it?

No it does not. I use(d) an android tablet, whatever you use just needs to have bluetooth and GPS capability.

[Mudderoy]

Uh Tony, this is above my pay grade but it sounds like this is not the easy way. On top of that I am not sure what you are trying to accomplish here

I'm working up to a more detailed description of a project I'm doing with a touch screen and external GPS module.

Smart phone, Mobilinkd (TNC), hand held HAM radio, and a cable to go between the TNC and the radio. APRSDroid software for your Android phone. Is all you need to start receiving APRS information. To transmit all you need is a HAM license.

The phone connects to the TNC via bluetooth. The TNC connects to the radio, and that's it!

[prerunner1982]

Uh Tony, this is above my pay grade but it sounds like this is not the easy way. On top of that I am not sure what you are trying to accomplish here

A lot of people use it to track themselves so others know where they are.
You can see where other hams are if they are also using APRS.
You can show what frequency you are monitoring so others in the area can contact you or any other short message (email, phone #, "Hello my name is Bob"... )
Areas of interest can be broadcast such as traffic accidents, location of repeaters, club meeting sites, hospitals, aide stations, etc.... anything you think other hams may need to know.
It was created as a situational awareness tool, to relay information relative to hams in a particular area.
Normally the program is set to allow the packet (information) to be repeated 2 times, so depending on how good the digital repeaters are it is not uncommon for me to see information from hams 100 miles away. You can set it to digipeat your packet more than that but it clogs up the system, however in an emergency it could be used to call for help as long as you are within the distance of one digipeater.

You can send a text message to a cell phone or send a short email as long as there is an internet gateway repeater within a hop or two of the digipeater you are using.

This is all done without the need for a cell network or internet.
In addition to terrestrial digital repeaters, the International Space Station has a digipeater on board, and there are a couple of digipeater satellites.

[prerunner1982]

My write up on APRS: http://www.xjtalk.com/showthread.php?t=20773

[bluedragon436]

Thanks guys... I'll have to look into picking up the TNC and a radio... and see if I can't manage to make use of either my tablet or one of the old smart phones floating around the house... might be able to see where the radio traffic is.. to be able to see if I can find folks to get up with or to learn from..

[prerunner1982]

Picked up a station from Cleburne, TX (214 miles)....San Angelo, TX (324 miles)..... and Eldorado, TX (365 miles)....Kansas City, MO (291 miles).... all on 2 digipeater hops. This is abnormal of course, but sometimes the propagation gods play nice.

I picked up a weather station from Lincoln Nebraska (372 miles) but for some reason the info did not tell me how many digipeaters it took to get here.

[prerunner1982]

If you use a mobilinkd tnc and tell the aprsdroid app to stop tracking you, but you leave the radio and tnc on it will continue to receive stations. That data will then be dumped into aprsdroid when you reconnect to the tnc. It will all show as being received at the time you reconnect.

Using the info above, I left my radio on the satellite/iss aprs frequency and left the tnc on to see if I pick up anything today....

[Mudderoy]

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[denverd1]

ok thats pretty cool

[Mudderoy]

Well some disappointing results. The pi and touch screen work great, but the APRS infrastructure in my area is lacking, at least for a 4 watt transmitter.

Looks like I'll need something in the 50 watt range to hit the digipeaters in the area, and as far as reception of APRS information, well I never received anything to display on my fancy touch screen with fancy map. Now that might change too with a better radio. HT's don't generally have discriminating receivers, like mobile radios do.

The plan is to make a cable to go between the ICOM 706 and the TNC. That way I'll have the power and the receiver. At this point I'm thinking having APRS available if I need it instead of APRS active as soon as I start the Jeep until I turn it off.

That may change in the future. What am I going to do with the computer?

Well it's a computer, lots of things I can do with it. One thing I was thinking about was loading up the Open source license plate reading software! Just need a camera and I'll start logging the vehicles to and from work! lol

Also thinking about podcast software, or loading up the car stereo software that would turn my pi into an infotainment system. Even watch TV with the right USB attachment!

[prerunner1982]

Not so easy any more? :D

Building the cable wasn't hard and I hope you will be more impressed with the results. Like I have said before, it worked much better for me than the HT did.

[Mudderoy]

Not so easy any more? :D

Building the cable wasn't hard and I hope you will be more impressed with the results. Like I have said before, it worked much better for me than the HT did.

Anything is easy if you know how. The problem here isn't easy the problem here is do I want to spend another $100 to make it happen. Then once it's done I still won't see the positions of other HAMs.

I thought you were following along on this Jon.

[Mudderoy]

Before I go any further in buying a 2nd high power radio for the Jeep I'm going to hook my stuff up to the ICOM 706 and see if it will do what I'm expecting.

So I ordered and receive a cable and a 6 pin DIN plug from Amazon.

TPPN for the Mobilinkd TNC2 and the 6 pin DIN for the back of the ICOM 706 MkII ModG

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Hooked it up to the 706 I have in the house and I'm able to do APRS with my cell phone.

Should work the same in the Jeep with the Pi setup. More to come...

[Mudderoy]

Sometimes it's easier to buy something to solve a problem than it is to test it and verify that the dollars spent is really the answer.

Fortunately I didn't throw money at this problem, well $12 but not $100+

I mentioned in a past post that I had a mag mount 2 meter antenna and a 4 watt boafeng dual band connected to my TNC and mobile computer, but I never even hit a local digipeater on the drive to or from work.

My assumption was 50 watts would do it. Now on my main 5/8 wave antenna and 50 watts out on FM I was able to hit the digipeater exactly ZERO times on the way to work this morning!

Now this isn't to say that having APRS capabilities in my Jeep isn't a good thing, it just means there's no reason to run it anytime I'm driving somewhere.

All I need is the cable that goes between my 706 and the TNC and the app on my phone. The cable can stay connected to my radio since it's using the 6 pin din plug in the back. So starting APRS operation is as simple as selected the frequency, pressing power on the TNC and starting the APRS app on my phone, or in vehicle computer.

Right now I'm leaning towards the phone and using the in car computer for something else.

I'm going to keep testing as I'm a little surprised that I didn't hit it once, at least while I was in my neighborhood. I do need to verify that I'm on high power and it probably wouldn't hurt to throw a watt meter on there and verify that it really is 50 watts.

Keep in mind that your APRS experience may be different. The distance you are form a local digipeater is the key. Also the number of them along your route.

I need to verify this but I don't believe a digipeater is necessary to share positional information with another HAM. You just need to be in close enough proximity for them to receive you and you them.

A lost HAM on the trail for example.

[prerunner1982]

Something doesn't sound right. There is obvious RF APRS activity in Houston, heck W5AUG can hit the Baytown digi from the middle of Houston. The SW side of Houston seems to be without a wide Digi but other than that I don't see why you couldn't get it to work every where else.

Did you receive any packets?
Did you transmit any packets? How many?

Houston APRS activity over the last 24 hours.

[prerunner1982]

Here is my APRS from yesterday, even running 30 watts it's not perfect.

Also my local APRS activity over the last 24 hours for comparison.

[prerunner1982]

I need to verify this but I don't believe a digipeater is necessary to share positional information with another HAM. You just need to be in close enough proximity for them to receive you and you them.

A lost HAM on the trail for example.

Correct.

[prerunner1982]

Have had problems lately with only getting one maybe two packets to go through, even when squawking at 65 watts. Looking at aprs.fi I am not the only one having very spotty coverage. Not sure if there are issues with the main local digi or what but have been really leaning towards putting up my own digi.