Poul-Henning Kamp wrote: > In message <[EMAIL PROTECTED]>, "Matt > Ettus" writes: > >> 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? >> > > All the ones I've seen are patches. > > I would suspect that the higher domes is a concession to weather: > when mounted on a building or tower, a steeper angle of the surface > will collect less snow and dirt. > > The old Datum and the current Micropulse timing antennas intended for cell sites, use a quad helix antenna plus several 1575.42MHz ceramic bandpass filters. The data sheets claim that the pointy ends also deter birds from perching on the antenna.
Novatel have a pinwheel antenna for precision applications as well as the traditional (expensive) choke ring antennas. These have the advantage of a reduced response to low angle multipath signals. Bruce _______________________________________________ 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.
