[time-nuts] Mounting GPS Antenna on Steel Roof

[Bruce Griffiths]

Brooke Clarke wrote:
> Hi Matthew:
>
> Some antennas are receptive to signals coming up from below.
>
> Since the signal is circularly polarized the first reflection is supposed to be 
> down something like 20 dB, but the second reflection will be much stronger, so 
> you would also need to look at those.
>
> Have Fun,
>
> Brooke Clarke
>   
Brooke

The interaction between the antenna and the roof is a near field problem 
and its more complex than one may at first suspect.
To achieve reasonable accuracy you need to either measure the effects or 
use EM modeling techniques.

Bruce