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How do you decide how often to send APRS?

kevinh

Well Known Member
I notice in the software there are options for how often to transmit position reports. Are there any 'best practices' to ensure you don't send too often?

I'm guessing that with the smart turning stuff turned on, the regular interval could be something like once every three mins and just count on the turning to cause a slew of new updates?

I'm new to all this.

I haven't received my microtrak yet, but fun reading about things. I'm initially going to test it with a spare wing tip com antenna I already have installed.
 
I notice in the software there are options for how often to transmit position reports. Are there any 'best practices' to ensure you don't send too often?

I'm guessing that with the smart turning stuff turned on, the regular interval could be something like once every three mins and just count on the turning to cause a slew of new updates?

I'm new to all this.

I haven't received my microtrak yet, but fun reading about things. I'm initially going to test it with a spare wing tip com antenna I already have installed.

Kevin, I am using the same intervals as Pete and the setup works very nicely. Since our planes cover a lot of ground, I wanted an interval much faster than three minutes (~8 miles). I use 45 seconds which gives an accurate indication of where the plane is at any particular time. It also results in fairly good accuracy if a beacon or two gets squashed by a stronger tracker. I think this is the current config I'm using:

tracker-4.jpg


But.........the MicroTrak is easily reconfigured so you can readily customize the device to your liking. If you wanted to get sorta tricky you could even use the secondary configuration to set up a different interval--maybe primary config for congested areas and secondary for flying in the boonies. :)

It is good to achieve a balance between accurate tracking and courtesy to others using the band so we don't needlessly hog the frequency. After you fly your tracker you will have a good idea of what configuration works well in your area.

We will be very interested in hearing how the Archer com antenna works with the tracker. If it works well, this will be a great application.
 
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Many APRS trackers support intelligent algorithms (like SmartBeaconing - http://www.hamhud.net/hh2/smartbeacon.html) to determine when to send packets. The theory is, if you're going in a straight line, you need to send packets far less often to maintain an accurate track. If you turn, you want to send a packet fairly quickly, so the turn is tracked properly.

I know the TinyTrack3 supports SB, but I'm not sure about other trackers. It might be something to play with.
 
Question on using a handheld xmtr

When using a 2 meter handheld how is the transmitter automatically keyed? i understand how the SW handles the dedicated unit but don't understand how a 2 meter handheld is used as a tracking transmitter.
 
When using a 2 meter handheld how is the transmitter automatically keyed? i understand how the SW handles the dedicated unit but don't understand how a 2 meter handheld is used as a tracking transmitter.

The microphone jack also has a PTT input (just like our av radios) - the tinytraker pulls that PTT signal to ground when it wants to xmit.
 
Thanks Kevin

i was not aware of the tinytrack encoder (or missed it) makes sense now...
 
I notice in the software there are options for how often to transmit position reports. Are there any 'best practices' to ensure you don't send too often?

I'm in general agreement with Pete and Sam that a shorter interval is better in airplanes. I have been using a one-minute interval (it makes examination of the data easier) without a single complaint for a number of years.

But what is even more important is the Digipeater Path parameter. Sam's example in the screenshot is what I've recently converted to: WIDE1-1, WIDE2-1. That's generally the recommended configuration everywhere nowadays. Earlier I had used WIDE2-2 but that used too much bandwidth when I flew near areas with multiple digipeaters. And I've never seen an instance where a path other than the recommended one is necessary, even out here in the mountainous West. For sure: NEVER use WIDE3-3 or more.

My TinyTrak3 implements "Smart Beaconing" and I've been trying to "dial in" the right settings to mark turns "more better". The other day I threw my portable tracker in the back seat to compare its parameters to the built-in one's and flew a lazy 360-degree turn around a small town. The portable tracker with "good" Smart Beaconing parameters did a very nice job:
http://www.mail2600.com/cgi-bin/track.cgi?call=K7JD-9&start=2008-03-06&stop=2008-03-06&elim=0
compared to the built-in tracker with less effective settings (the turn in the north is not even noticeable):
http://www.mail2600.com/cgi-bin/track.cgi?call=K7JD-7&start=2008-03-06&stop=2008-03-06&elim=0

--
Joe
 
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