[time-nuts] Important parameters for a GPS/GNSS antenna

Attila Kinali attila at kinali.ch
Thu Apr 30 13:37:12 EDT 2015

On Thu, 30 Apr 2015 17:19:22 +0000
Gregory Maxwell <gmaxwell at gmail.com> wrote:

> I have no experience in the subject, but one parameter I didn't see
> you mention is front/back ratio-- it should have the lowest gain
> possible for angles below whatever you would horizon mask in order to
> suppress multipath coming in from lower elevations.

Yes, radiation pattern is probably the first thing to optimize.
But low angle/back lobe damping is rather "easy" to acheive by
some EBG around the antenna (like choke rings). Integrating into
a compact antenna is much more difficult.

> Operation at all the relevant GNSS bands would be good to optimize for
> too, and might be a major motivation for a new public design as
> multibanded antennas for timing applications are quite costly and
> tough to find surplus.

A tri-band antenna design is... uh.. difficult.
At the moment I am just playing with some software. Yes, I might
end up with something that resembles an antenna design. But with my level of
knowledge getting a good single band antenna would be already quite
some feat. Designing a multi-band antenna is way out of my league.

			Attila Kinali

It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
                 -- Miss Matheson, The Diamond Age, Neil Stephenson

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