[time-nuts] gps timing antennas

Bruce Griffiths bruce.griffiths at xtra.co.nz
Wed Feb 13 05:20:46 EST 2008


Matt Ettus wrote:
> Is there really anything in particular which is different about the
> antenna requirements of timing receivers as compared to ordinary
> high-quality receivers?  The timing antennas seem to be in pointy
> radomes, so that tells me they are probably quad-helixes rather than
> patch antennas.  How is that advantageous for timing in particular?
>
> Thanks,
> Matt
>
>   
Matt

Quad helix antennas have less falloff in response towards the horizon
than others which can be problematic with multipath signals.
Other antennas like choke ring antennas and other types (Trimble and
Novatel have less expensive variants) are better in this respect.
Most timing antennas, especially those intended for cell phone sites
have dual or triple L2 bandpass filters which can be effective in
reducing the effects of interference from other signals.

Bruce



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