Thursday, August 25, 2016

APRS Tracking on the Cheap

Are you a new ham looking to experiment with APRS? Maybe you want some cheap trackers to use for a public service event. If you've been looking for an inexpensive APRS tracker, look no further!


If you have searched for trackers online, you will notice the cheapest is somewhere around $40, and you still need to supply a GPS. I'll show you how to use a cheap android phone, a cheap Chinese HT, and a simple cable to make an APRS tracker in True Ham Fashion!
Baofeng UV-5re Plus w/Extended Battery
First you will obviously need a radio. The Chinese have saturated the market with very cheap handheld transceivers. You can easily go to Amazon and pick up a Baofeng UV-5r for about $30. While these are not of the highest quality, they do work well.
Cheap Android Phone
The next item on the list is going to be a cheap Android phone. With all the prepaid services out there now, you can find these things REALLY cheap and you don't need to buy the cellular service plan to use them for this project. Cheapest as of this posting is $10 from Wal-Mart. The phone will give us the platform for running our APRS software and it has a GPS built right in!
3.5mm Male to Male audio cable
The third thing you will need is the audio cable to connect your radio to your phone. If you chose the UV-5r series of radio, you will need a simple 3.5mm AUX audio cable. This should run you around $3.
APRSdroid Sending location updates
I almost forgot, you do need software on the phone to actually run APRS. Don't worry because you can get this for FREE. aprsDroid is an app that you can put onto any Android device. You can download it for free from (https://aprsdroid.org/) and if you really like it, look it up on the Google Play store and buy it. Just a quick note, if you are new to APRS and just looking to mess around, the app is great. It will connect you to the APRS-IS system via your cellular or wifi connection and you can use it as a stand alone tracker if you have a data plan. Too bad there is no equivalent for iOS devices.

To get started setting up your tracker, put the app on your phone and configure the settings. You will want the app to send updates via AFSK through the speaker/mic on your phone. While you are in settings you will also notice a section to get a passcode for accessing the APRS-IS system, I would follow their instructions and get one. You will probably want it eventually even if it's not necessary for this project. The final setting is for your SSID. I usually use CALLSIGN-7 if I'm using a radio and CALLSIGN-5 if I'm just using the phone stand-alone. By default SmartBeaconing is enabled, and I tend to leave it setup this way.

On the radio, you will want to enable VOX. I usually set mine to a level of 1, but I've heard that it can vary slightly in the cheap HTs. Set your frequency to 144.39 and plug the audio cable from the MIC jack on the radio to the headset jack on the phone.

Once everything is plugged up and the app is running, you can hit the "start tracking" button on your phone. Once GPS reception is locked on and the phone knows where you are, it should send the audio signal to your radio and transmit your current location data.

I've used this method for a while now with really good results. The only limiting factor is battery life. I managed to get about 8-10 hours out of my radio on 4 Watts using an extended battery pack, but the phone won't last long with the GPS turned on full time. Depends on the phone, but if you need longer run time I would suggest getting a bigger power source for the phone and/or radio. Depending on the digipeater coverage in your area, you could also try turning your transmit power down to save radio battery life.


2 comments:

  1. Such a tracker is indispensable for the organization of the global event, for sure its device great. Is this a radio signal? Do I understand correctly? I found out a lot of information about software tracking system https://uboro.io/. As my colleagues say, this is one of the most effective applications of this kind. Well, I intend to see this personally.

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