Matt, The dome type antennae usually found in timing receivers do have a couple of additional features over flat patch types.
1) Physical design for better performance in rain and snow (especially the latter). 2) Additional filtering for improved performance in high noise environments. On this, I quote personal experience when installing a Datum product a few years back on a TV transmitter site. The second harmonic of one of the channel carriers was very close to the GPS L1 frequency, and the receiver had problems tracking. We changed the antenna to a Trimble Bullet II HE (?) which had a 3 pole filter, and problems disappeared. I'm currently using the Vic-100 from Matsushita http://pewa.panasonic.com/emp/products/gps_pdf/vic100_2004.pdf here in the UK on my Odetics CommSync (antennae inside building under a concrete roof). Rob Kimberley -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Matt Ettus Sent: 13 February 2008 09:22 To: Discussion of precise time and frequency measurement Subject: [time-nuts] gps timing antennas 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 _______________________________________________ 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.
