[aprssig] APRS antenna for an airplane

[Dave Kaplan]

Below is a quote to give you something to think about if you are doing a
clean install. This quote is taken from an excellent article that can be
found at:  http://www.hamtv.com/pdffiles/ATVinAcft.pdf
<http://www.hamtv.com/pdffiles/ATVinAcft.pdf> 

"... I realized that the braid of the RG58 coax to the antenna would
vibrate enough to change contact resistance between the strands and that
would show up as an AM modulation from SWR change. The solution is to
use Teflon double shielded coax with tight braid or aluminum foil. I
suggest RG400, which you can possibly get from companies that do mobile
cellular phone installations, or RG162."
 
I use to run APRS while flying a Tubine Commander and later a King Air
200 but now I am flying a Citation (and going 100 MPH faster) I don't
have the down time anymore in the cockpit.
 
Dave
WB0WNX
 
 

-----Original Message-----
From: aprssig-bounces at lists.tapr.org
[mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Glenn Wiebe
Sent: Saturday, September 16, 2006 11:21 AM
To: aprssig at lists.tapr.org
Subject: [aprssig] APRS antenna for an airplane

Would mounting a 1/4w vertical or similar antenna on the belly of an
aircraft not create a null area directly underneath the plane? I
remember the pilot of a Jet Ranger under contract to the company I
worked for at the time telling me that they would not install it there
for use with our company 179 mhz radio for that reason.

73 de Glenn...VE4GN

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