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There are a variety of websites that give sample SmartBeaconing™ settings – mostly for automobiles, but some for bicycles and pedestrians. I've tried several of these settings and had mixed results. Can anyone share a set of experimentally-verified ideal settings for any of the following?

  • Driving on-road
  • Driving off-road
  • Walking on streets
  • Hiking
  • Bicycling on streets
  • Bicycling on trails

Assume that we're within the coverage area of a moderate-traffic digipeater (my reference is N7HND in Tucson), so we can be reasonably certain that most of our packets will get through, and we don't want to flood the frequency. In other words, this is not a question about how to configure a mobile APRS station for best coverage, but about how best to take advantage of an effective station setup.

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  • $\begingroup$ I'm talking about digipeaters operating on standard APRS frequencies, specifically for the purpose of repeating/gating packets. $\endgroup$ – Rafael KR7MJ Aug 9 '17 at 8:08
  • $\begingroup$ This is an interesting question. One sticking point is what is "ideal", ie optimized in what sense? $\endgroup$ – Malcolm VE2DDZ Nov 18 '17 at 2:27
  • $\begingroup$ My working definition is: beacon frequency is high enough that determining a station's current position doesn't involve much guesswork, but not so high that a significant number of stations can't share the digi/frequency without packet clobbering. $\endgroup$ – Rafael KR7MJ Nov 19 '17 at 21:26
  • $\begingroup$ I've worked public service events where net control needs to know every mobile/portable station's position to a pretty high degree of accuracy – i.e. to within a hundred feet or so – for safety reasons. A station driving their car at 20 mph on a dirt road and beaconing every 5 minutes doesn't cut it. A station on foot beaconing every 30 seconds is overdoing it and clogging the frequency. $\endgroup$ – Rafael KR7MJ Nov 19 '17 at 21:27
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I think it's going to be difficult to find experimentally-verified values because the experiments haven't been conducted. (Maybe you want to volunteer :).) There is also a lot of subjectivity here because the accuracy required is going to vary greatly by application and situation, and the amount of APRS traffic in an area is going to dictate how frequently a station can send telemetry without causing congestion on the APRS frequency.

Where I live (southern Saskatchewan, Canada) there are quite few APRS users and only a couple of digipeaters and iGates covering a very large area of land. I have the luxury of being able to send quite a lot of packets without causing flooding. On the other hand, next week I'll be in the Dallas-Fort Worth area and I imagine such frequency of transmission won't be as welcome there because of such a large number of people in such a small area, and presumably, a commensurate number of APRS transmissions plus better infrastructure.

The beaconing on my Yaesu FT-400XDR allows me to configure telemetry transmission by direction change, speed and time. The slower you're going, the fewer packets you need to send. The more often you're changing course, the more often you need to send. At a point, even if you're motionless, you want to send another packet to confirm that you are still in the same location. But what is the exact delay you should use? It's so hard to be concrete because it depends on the purpose. In my case, I send out the packets because I experiment with APRS, I want hams at home to be able to see where I am and I want the opportunity to chat with other hams while driving. Packets sent every five minutes are probably adequate most of the time for what I'm doing. As you point out on your question, though, people on foot doing emergency communications might need to send out packets quite often.

Remember, too - the more packets you send, the more of a hit you'll provide to the APRS transmitter's battery, if its portable. So that's yet another consideration.

So - in summary - I don't think anyone can give a blanket recommendation, just some general things to think about, and then some local experimentation is going to be required.

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