W5AOX APRS Data, Setup, Etc.

I've been active in APRS for several years now, and it is still one of my ham radio obsessions.
Here's some of my experience with the mode, the hardware, software, etc....
First of all, DON'T fly off and purchase one of the Delorme Tripmates or Earthmates off the internet or Ebay.
The average final bid price for these units has been around $50, not including shipping, and they are outdated and overpriced at this level,
UNLESS you get Street Atlas software along with it.
There are several vendors on ebay and elsewhere selling the newer Globalsat GPS-pucks which are smaller, more sensitive, and faster locking.
Plus, they're easier to wire up. And ~ they sell for about $60 single unit quantities.
Try http://byonics.com/ for gps units with connectors already set up, in this price range.

Here's what most of my APRS systems consist of:

Here's what APRS with a Kenwood DataRadio looks like:

Much simpler with the Kenwood TH-D7 (Handheld) or the TM-D700 (mobile). If you have the money, this is the way to go.
However, for dedicated APRS use, since only one channel is generally used, an old crystal controlled or early synthesized radio will work fine.
One of my most reliable APRS units uses a 30-year old VHF Engineering 1 Watt transmitter strip for the "2 Meter Radio".
It runs all the time, even with ignition off, and never gets "unprogrammed" or stops APRS activity because "somebody punched the wrong button" or
it's being used on another mode or channel.

Wiring Diagram for the Globalsat BR305 GPS receiver:

APRS Misc. Notes and Thoughts:

  • The APRS network is CLOGGED with weather, traffic from non mobiles, beacons from hundreds of miles distant, etc.
  • DON'T be disappointed when your mobile does not get most of its positions reported. It must compete with literally
  • dozens of higher powered base stations and digis in your area, most of which are beaconing constantly and wiping out much of the mobile position packets.
  • However, the APRS system is STILL very usable even with its limitations. You can help in lessening the channel traffic
  • by limiting YOUR beacon repetition rate. Every 10 minutes is quite a few beacons over the course of a highway trip.
  • If you can enable "smart beaconing", you can set it to beacon less as your speed goes down and vice versa.
  • Mine are set to beacon only every couple hours when sitting still, making it more difficult to be "Tracked" while in a parking lot.
  • Then my beacon rate increases to every few minutes when above 40 MPH, so fairly accurate tracking is available.
  • If you don't want to be "tracked" then TURN your RADIO OFF, BEFORE you get too close to your "secret destination".
  • On a long trip I find it useful to just leave it on. That allows the "fam" to see I may be pulled off in a rest area:
  • If my time shown in a rest area is more than a few minutes, they can see I'm stopped for a while or taking a nap.
  • If I'm broken down somewhere my APRS would make it fairly easy for someone monitoring my position to direct help to my exact location.

  • Spy on Jim's Car via APRS
  • Spy on Jacque's Truck via APRS
  • Spy on Our RV via APRS

    Email :jdport at sandia dot net