Many events add APRS with great hope and failure in a predictable sequence. Been there, invested a lot of work only to see failure. Why, simply because nobody used the valuable information. Many hams are great verbal communicators, but this does not mean they can use computers, read maps and create a visual picture of the situation (Situational Awareness or “SA”). For success, follow I would this sequence:
1. DEFINE PURPOSE – MOST IMPORTANT!
In most cases the purpose is to visually track assets. This also means that the HQ location(s) needs proper equipment;
- Ability to receive APRS (RF and/or through the Internet)!
- Ability to display the information in a clear way usable by decision-makers!
- Net Controller(s) or HQ personnel MUST embrace its use!
2. DEFINE THE DATA NETWORK
- Will this be a pure RF Network, or
- Will this be a pure Internet based Network, or
- A Combined Network
I usually combine the networks to take advantage of all APRS tracker types. This also simplifies the HQ setup since it only requires Internet access and an iPad to drive a large screen or projector display. As i simply describe it – dump all available data into APRS-IS and then you have numerous simple ways to display it in numerous locations and formats.
3. VHF INTERFERENCE
Let’s realize it, if the comms are on VHF, and APRS is also beaconing with an antenna a few inches next to the voice radio, it will affect the voice communications in the vehicles. The data blurp will, at best, de-sense the voice radio but may even be heard if tone squelch (PL) is not used. This is, of course, very annoying to the ham voice operator. Use of UHF for voice is thus preferred. At this point a duplexer will allow for single antenna installation for the shared purposes.
4. DIGIPEATERS & I-GATES
Unfortunately, the APRS digipeater coverage is dwindling since use of packet radio is also dwindling after the Internet became mainstream. However, many shacks still have the equipment laying around to create temporary digi’s and a (few) strategically located I-Gates will solve the problem. In my “kit” several of my mobiles will act as digi’s and I have 3 I-Gate/Digis to be deployed (information on this website).
5. TABLETS / iPADS / DISPLAYs
Use of tablets (iPad or other) is a great tool also in the field (mobile, SAG etc) to maintain situation awareness the other resources. When I am the event coordinator, it allows me to roam and still have the big picture.
APRS ON CELL PHONE
It’s a great concept. I find that it usually fails for numerous reasons:
- Battery dies quickly (it does not allow the phone to sleep)
- APRS App sleeps when not the primary app is in use
- Phone times out and sleeps
- Cell coverage
To create success, make sure the cell device is always powered (not sleep) and a (mobile?) charger used.
If the phone owner is an avid APRS user, the above problems are quickly minimized.
The success begins with defining the need to display the situational data, not just another cool idea/tool that works without planning.
ONE PUBLIC SERVICE EVENT’s USE of APRS
Annually, we coordinate a Downriver Canoe and Kayak Race. 2 school busses are used to transport racers and spectators. Each bus has a standalone 10w APRS tracker with power from the bus or AA-batteries. The voice operator is on the local UHF repeater, thus no interference from the VHF beacons.
In RACE HQ, 2 iPads supply detailed information on each bus location. Thus, they are dispatched based on efficiency (nearest to pickup point) without the proverbial “where are you” question at the beginning of each exchange. It also allow the race coordinators to be in the field and see the same map remote.
The nearest full time digi is located about 15 miles to the south and has 75% “enroute” coverage. We add a digi/iGate at each end of the race to create 100% coverage.
By using the internet as the transport media it also allow display(s) in my car and on my cell as I roam the event.