On 12/03/2012 05:32 PM, skanderup wrote:
>
> Hi,
>
> Now the talk is on antennas, I would like to ask the forum for your guidance
on ground plane.
>
> I have purchased a nice antenna for my transponder and it requires a ground
> plane
(which a GP aircraft does not provide automatically like a metal plane...)
I hope you bought the TED antenna as it is the best available and also
very affordable.
A ground plane should be at least a quarter wave in radius. Quarter wave
is the lenght of the antenna rod. A larger ground plane is ok, but has
not much additional benefit.
In my tri-gear I cut out the monowheel opening and use an aluminium
plate to cover it. I mounted the antenna on the underside of the metal
plate, and it works very well.
As these radio waves are going through the glass fuselage, you could
mount the antenna somewhere inside as well, and use any metal plate
available. It is advisable to mount the antenna "upside down", that is,
the metal rod sticking down. Beware of "shadows" like from the engine,
so keep it as low as possible.
Frans
|