europa-list
[Top] [All Lists]

Re: Transponder Aerial Location

Subject: Re: Transponder Aerial Location
From: Fred Fillinger <fillinger@ameritech.net>
Date: Fri, 3 May 2002 16:56:27
> >The signal has to be sent back down to earth so the ground plane is
> >uppermost and the ball end pointing down.
> >
> >Tony
> 
> The same logic applies to the COMM antenna, yes?
> 
> Graham
> 

Not really, though pointing up isn't quite as good, but long antennas
on the bottom have other compromising issues on small aircraft.  1/4
wave whip antennas are a practical necessity where size matters in
mobile installations on metal structures.  At fringe reception
distances from ground stations, at altitudes we often fly, the angle
---From it is only a few degrees from horizontal.  As such, the inherent
gain in the 1/4 waver isn't being utilized anyway, making the dipole
the most efficient, because the signal is strongest near the
horizontal.

Best,
Fred F.


<Prev in Thread] Current Thread [Next in Thread>