APRS On The Cheap
Building an APRSDroid system using information from the internet
I have been wanting to build a simple APRS tracking device. No good reason. Just wanted to build one.To that end I have been reading various web sites and posts about using an App call APRSDroid on an android phone with the Baofeng UV5R Chinese radio.
- http://k6vhf.com/baofeng-and-aprsdroid/
A youtube video on using APRSDroid and the UV-5R:
- https://www.youtube.com/watch?v=8-9_8HVkvgc
The APRSDroid site:
- https://aprsdroid.org/
A site to roll your own cable:
- https://willbradley.name/2015/08/09/aprs-via-rf-cable-for-connecting-aprsdroid-to-a-baofeng-radio/
A really good Instructable:
- http://www.instructables.com/id/APRS-and-the-UV-5R/
I already have the radio.
For the android phone I sent an email out to some friends to see if anyone had an old one available. I ended up with two. A Samsung Galaxy Note 3 and a Motorola Moto E.
Here's the Samsung.
As you can see, I familiarized myself with the Galaxy, logged onto the Google Store and downloaded the APRSDroid App (cost $4.95). The next step was to request an ID from the creator of the App. I received it a day after requesting it. The software works very well via the wifi connection!
Now I need to get a cable to connect the radio to the phone. I have been looking at several sites on how to build these cables. On a search of Amazon I found they sell the cable pre-built. $18 later it is on order with an arrival date of 22 March 2017.
The cable can be found here on Amazon:
http://www.amazon.com/gp/product/B01LMIBAZW/ref=od_aui_detailpages00?ie=UTF8&psc=1
It includes the APRS-K2 Cable, Reverse Connector Adaptor and a Quick Start Guide.
The cable arrived and I spent some time hooking things up, reading on the web, and setting options. After a bit it worked!
Total cost:
- Baofeng UV5RT dual band HT: free (won 15 months ago at PARK Christmas party)
- Motorola Moto E android cell phone: $10.00
- Cable to hook them together - $18.89
- APRSDroid app from google play - $4.99
- A few hours of my time (Hey it was this or reruns....)
Some of the things I needed to do for this to work:
Radio:
- SQL = 1
- VOX = 5
- Volume up 1/3 from on
APRSDroid:
- Position Reports > APRS Symbol = \- (Shows as a House with an antenna)
- Position Reports > Location Source = SmartBeaconing Position
- APRS Connection > Connection Preferences
- Frame Sync preamble = 800ms
- Audio output = Voice call
- Hi Quality Demodulator = Checked
- APRS Connection > Connection Protocol = AFSK via Speaker/Mic
- With cable plugged into headset/mic connector = Use rocker on side of phone to adjust audio to the lowest level, then bump it up one time.
AND!
- The stock HT antenna just did not cut it to get out to the nearest node. So I used a mag mount sitting on the desk and it worked fine.
Putting it in the car
I put the setup for APRS in the car for testing. I started doing this a few days ago so I have several work days of experience now.I turn the phone with APRSDroid and the radio on for my drive to and from work. Then check how it did using aprs.fi.
I was expecting reliable pings from the APRS setup to march along my route and show me the track on aprs.fi, but this is not to be. Some days it is good and most days it is marginal. I've tried a couple of different mag mount antenna with limited improvement. Here's an example route showing the actual route and the APRS route.
Tomorrow I add an amplifier so the output power will go from ~5 watts to ~20 watts. The idea is... since this is a shared channel, it is possible I am getting stepped on by other users who cannot hear me and are putting a stronger signal into the I gate. A bit more power may help. We shall see.
It is tomorrow and here is a track with the amplifier added to the HT.
The track is much more precise.
Looks like this may be a good way to break into APRS... at least to get your feet wet.
Thanks,
Mike
N5BGZ