posted by George AE7G
I first have to confess that while I love using APRS in public service events, I am far from identifying myself as an expert in the technology.
The Columbia Winery charity run event is a great place to test out technology. The event is pretty easy, almost nothing ever goes wrong and there is plenty of time to test new things and work out kinks.
Since I became involved as team lead for this event, we have been making greater use of bicycles to patrol the course and track walkers and runners. Any halfway fit bike rider can easily keep up with even the fastest runner.
APRS allows command to easily track support team members and determine allocation of resources. With the use of a decent APRS mapping program such as APRSIS32, it becomes very easy to track your resources in the field. This is both an excellent tool for managing events and a good way to impress observers. Just use a simple projector to project the image on a screen and suddenly your net control operation becomes professional.
This year we were trying out a mapping program (APRSIS32) that was new to me. We also had a variety of radios and cell phones to be used by bicyclists to beacon positions.
While APRS was for the most part a success during this event, there were a few glitches and lessons to be learned.
I want to thank Scott Currie, who is a genuine APRS expert for his help and guidance.
- Handheld radios have very limited range and their ability to effectively communicate APRS positioning can be compromised in some rural or other difficult coverage areas. Bicycles are not great vehicles for mobile radio use, so in many cases handhelds or other lightweight tools may be the only option.
- Coverage can be improved by adding mobile stations along the course. These stations can pick up and echo forward the position of stations with weak transmit capability.
- Coverage can also be improved by changing the packet forwarding protocols. Protocols set the number of “jumps” authorized by the beaconing user. Broader protocols increase the chance the position will be picked up and eventually get into an internet gateway (IGATE). Excessively broad protocols clog the APRS network.
- In a difficult area it is a good idea for the mapping program to make use of both (internet) and RF (direct radio) transmissions. That improves the chance of receiving position reports;
- Many radios have so-called “smart beaconing” protocols to vary the rate of transmission. In general these programs transmit positions more often when the station is moving, less often when the station is standing still or traveling slowly. Radio smart beaconing programs can vary from radio to radio. Most of those programs are set up for motor vehicle use, it is probably a good idea to disable smart beaconing on a device being used on a bicycle. Instead, set the radio to automatically beacon a position on a short interval, probably once every three minutes. The “off the shelf settings, particularly in the Kenwood radios, may not be ideal for bicycle use.
- To impress the Event Director team, it makes sense to provide a tablet that shows key tracking positions. By making use of “alias” identifications the APRS mapping program will be more understandable and have greater value to event leadership.
These are easy lessons to learn. I look forward to applying them next year.