Hi Obviously this becomes a “that depends” sort of question. For timing, you probably can do a fine job with an antenna that nukes everything below 20 degrees to the horizon. That *assumes* that you have a good enough view that it does not pull to many sat’s out of your population *and* that you already know your location.
Phase / delay stability over temperature would be an interesting thing to look at. Probably not a big deal on a simple antenna. It might be an issue as the antenna interacts with the preamp and filter. Bob > On May 2, 2015, at 12:36 PM, Magnus Danielson <mag...@rubidium.dyndns.org> > wrote: > > Attila, > > On 04/29/2015 10:43 PM, Attila Kinali wrote: >> Moin, >> >> I recently discovered openEMS[1], which is, very simply put, a fancy >> antenna simulator. I played a little with it and thought about >> trying to optimize an GPS patch antenna design for timing use. > > Will take it for a test-drive to see how it align up to NEC2 and variants. > >> But I had to discover that I actually do not know what to optimze for. >> There are many paramters I can think of (RHCP/LHCP, symmetry of >> gain, feedpoint impedance vs frequency, stability of phase centre,....) >> which all seem to be to some extend important, but which ones do actually >> matter for the timing reference performance? >> >> My google skills failed to locate any relevant documents on this topic. >> >> Could someone be so kind and give me some pointers, what to search >> for, documents or the like? > > The thing that we care about is: > > 1) LHCP surpression > 2) Directivity/ surpression of signals below say 5 degrees above horizon > 3) Phase stability with regard to azimuth/elevation > 4) Relatively flat gain above 5 degrees > > Do read up on the Novatel pinwheels, as they illustrate the various concerns > and how they do that in a new fashion. > > Cheers, > Magnus > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.