[time-nuts] Choke Ring Design for L1
Bruce Griffiths
bruce.griffiths at xtra.co.nz
Sun Mar 14 11:39:48 UTC 2010
Peter Vince wrote:
> As I understand it, the GPS signals are circularly polarised, and so
> surely reflections will reverse the sense of that polarisation such
> that the antenna will be insensitive to them? Maybe Warren's simple
> pie dish is working by shielding the antenna from the true MULTI-path
> reflections, and any direct SINGLE reflections it produces are ignored
> due to the polarisation reversal?
>
> Peter
>
>
But the incident wave is diffracted at the edge of a finite ground plane
creating a surface wave that the patch antenna element does respond to.
Unless one has a microwave anechoic chamber one has to calculate the
antenna response with an EM simulation program.
Its not possible to infer an antenna's response to multipath by merely
measuring its apparent response pattern to a GPS SV except perhaps when
one has a detailed and accurate EM model of the antenna environment.
Bruce
More information about the time-nuts
mailing list