Weetabix wrote: ↑Fri Mar 26, 2021 7:51 pm
APRS question - what is the draw in telling the whole world, "Here's exactly where I am?"
Since I am primarily interested and active in Emergency Communications, APRS helps with tracking resources and cutting down on voice traffic.
It's also one of those things that you need to practice using regularly or you find you forget some of the nuances that can trip you up if you need it in an emergency (when you've got 500 other things to do right now.
Example; We use it every year in public service events (Including the Air Force Marathon) to track the lead runners of the various events and where Tail End Charlie is. (We have trackers with bicycle riders with the runners and in the chase car at the end of the pack). This keeps the "where is...?" traffic down on the voice frequencies, keeping them clear for emergency traffic. I run the net control station in the command post and the race officials like being able to look at a map and see where everything and everyone is. And having that display means they aren't asking me same question every couple of minutes
In other events such as long bike rides we have trackers in our SAG (Support And Gear) vehicles. If a rider calls the incident command on their cell with a mechanical or minor medical problem, we know where the nearest SAG on the course is and can vector them in to the rider over voice either by radio if they have an operator in the vehicle, or by cell if they don't.
All of my family are licensed and each of our vehicles have Kenwood APRS radios. It's a nice way to see where everyone is and to flight follow a family member when they take a long trip. I've used it to vector Darlin' Daughter around a major interstate traffic jam on surface streets and back onto the interstate below the back up.
I know of at least one case where someone used an Emergency beacon to get help in an area with no cell service
I know of at least two cases where a ham's stolen vehicle was recovered because the crooks didn't understand that the radio was also beaconing their position.
And APRS is more than just "Here I Am". I can pull WX reports from local APRS enabled weather stations, send and receive text message without using my cell.
If you're paranoid about transmitting your position there are a few things you can do:
1. Don't enable the Beacon function. You can receive everything but not let the system know you are there.
2. You set Position Ambiguity in your radio so that it does not transmit a precise position. It only shows you in an area (how large is defined by how your set your ambiguity).
3. You can set the Datum used by the GPS to a non-standard one, thus throwing your displayed position way off your actual.
And if you carry a Cell phone around, you're already being tracked with a much more detailed record of your activities that anyone could get off APRS.