[aprssig] airborne digi

[Kriss A Kliegle]

Little late...was out at Oshkosh for the airshow all week.

Heads up on what to expect:

  At altitude in a suburban area, the RXR will be continuously pounded by packets. I routinely fly KA1GJU-6 from sea-level to FL370 using a Yaesu VX-1R and can watch the RXR's S-meter.Once aloft and east of the Mississippi river, it's usually constantly busy. I actually turn the radio's sleep feature to 2 sec (it's max) and turn the volume off to save the little one cell, Li-ion battery. No need to run the battery down listening to all the packets.

   Therefore it may never TX a peep until you reach a lower altitude, especially if the DWait time is anything other than 0. I suppose you could use a -dB antenna such as a 2" stubby duck to reduce the incoming packets( i.e. act as an attenuator)  but then you'll be seen only the folks directly below you and those further away will only be digi'ed unreliably as you bank and move about at altitude. The "Golden Rule applies here:

"SUCCESSFUL APRS: The success of your local APRS is not how many stations you see on your maps, nor how far away, but how reliably your mobile or handheld or portable station can communicate with others in the local area. . There is a big difference and they are mutually exclusive. . This fundamental principal should drive everything we do with APRS in our local areas"

   Might be more fun to use the setup as a tracker, beaconing that you are available on UHF (no desense every time your tracker fires off on 144.39 if you are on 146.52) or in the high end of VHF simplex frequencies such as 147.570 and work folks on voice. I think you will find very few QSO's generated by someone actually observing their screens/radio faceplates and actually QSY'ing to the discrete frequency you were beaconing. My own experience tells me that after a 3 or 4 day trip, (15 to 20 hours of actual flight time), I may get one or two responses. These will consist of either somebody attempting to send me a msg via APRS (RF) or an actual email asking about more info on my setup. Unfortunately many users are beaconing away endlessly, but few are receiving and actually looking at the data presented and using APRS as it was intended... for local communication.

  Anyway, we will probably see the SIG get lit up with folks arguing about what the proper thing to do. (Would be a nice change from all the banter about WXSVR eh?)

Kriss
KA1GJU -3, -6, -7, -8, -9


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