[aprssig] Aeronautical Mobile Best Practices?

Joe Dubner jdubner at gmail.com
Sat May 28 17:01:44 EDT 2011


Here's my idea of "best practices" gleaned from more than 1000 hours of 
flying time over the past 8 years:

1.  Use a PATH of WIDE2-1.  Period.  WIDE1-1 (and other WIDEs) are 
neither necessary or useful.

2.  Anything will work at 10000 AGL but a good (usually external) 
antenna is necessary if you want to get coverage at low altitude.  I've 
done "antenna shootouts" with other aircraft on the same route and the 
antenna makes all the difference difference (power doesn't).

3.  Don't use MIC-E; use plain ASCII.  This doesn't take a lot of extra 
bandwidth  considering all the wasted bits with extra flags for TxD, 
etc. but makes troubleshooting long-delayed packets a whole lot easier. 
  In addition, not all MIC-E packets are decoded correctly; my error 
logs are filled with things like: "Parsing failed: Invalid characters in 
mic-e information field (mice_inv_info)"  Just today there were a couple 
dozen of these and other errors reported by the FAP.pm parser.

4.  I've had no trouble flying at medium altitudes (up to FL190) in the 
western US with CD /enabled/ and I suggest you try it, although YMMV.

5.  30-second or 60-second beacon interval (depending on the location) 
works well.  You can't xmit too often over northern Nevada <g> but once 
a minute near populated areas, especially if at altitude, is appropriate 

6.  I have a few more "best practices" for the TinyTrak3 but they don't 
apply your HT so I'll keep mum unless asked.

Regarding voice operations, I've used an Icom IC-706 on 2m FM for voice 
QSOs but I only wired its headphone output into the intercom's music 
input.  For xmit, I used the Icom mic (and PTT) while wearing my 
aviation headset.  It's not ideal without sidetone but it's do-able and 
simple to implement.

Besides the usual resources, there's a mostly-inactive Yahoo group 
(http://groups.yahoo.com/group/aero_aprs/) where questions could 
theoretically be answered.  And this web site (mine) specializes in 
displaying airborne APRS: http://www.mail2600.com/cgi-bin/everyone.cgi

Have fun!

Joe, K7JD

> From: Bob Snyder <rsnyder at toontown.erial.nj.us>
> Subject: [aprssig] Aeronautical Mobile Best Practices?
> To: aprssig at tapr.org
> Anyone have a pointer to a list of best practices for running a HT
> aeronautical mobile? I picked up a TH-D72A last weekend at Hamvention
> and was considering taking it up on 250nm flight I'm planning this
> weekend. I know the recommendation for balloons is direct only and to
> disable carrier detect since you'll never hear a quiet spot if you
> don't, but I'm not sure if that makes sense up at six or seven
> thousand feet AGL. One homebuild aviation site with an APRS subforum
> suggests WIDE2-1 which I'm unsure of.
> Also debating trying to hook it to the intercom system and monitor a
> simplex frequency while flying, but I need to double check that a) the
> copilot side intercom input won't be sent to ATC if only the pilot
> side PTT is depressed, and b) the legality of retransmitting ATC
> broadcasts if they call me during while I'm speaking to the D72A. Plus
> figure out the cabling.
> Bob

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