Chuck, I usually see GPS antennae flashed by lightning: have succedeed opening and repairing a couple of them but at times they are too bad to do anything. I use a network analyzer to test them after repairing here at work.
On Tue, Apr 3, 2012 at 8:24 AM, gary <[email protected]> wrote: > Going back to software filtering brings us full circle. ;-) > > Searching the interwebs, I found this: > >> http://www.ll.mit.edu/mission/**aviation/publications/** >> publication-files/atc-reports/**Dinius_1995_ATC-238_WW-15318.**pdf<http://www.ll.mit.edu/mission/aviation/publications/publication-files/atc-reports/Dinius_1995_ATC-238_WW-15318.pdf> >> > > They more or less state the obvious, but do provide some test results. Now > the obvious is you want good cross polarization, i.e. the ability to reject > the wrong polarization. Basically the intended signal is RHP, but the > direct bounce is LHP, so you want the antenna to have good RHP gain and > poor LHP gain, or more accurately, the ratio between the two. > > The next source of interference is the bounce from the ground, which could > be multiple hops and thus potentially RHP. That is where a ground plane or > choke ring came in handy. > > Page 37 has the conclusions. > > I have a similar Trimble patch somewhere (Trimble 16248-50). It has never > seen action (at least by me) since the voltage requirement is quite odd. I > don't have it in front of me, but I think 4.5v. That particular antenna > also has a SAW filter in it. It is a Navy item. > > > > On 4/2/2012 10:15 PM, Hal Murray wrote: > >> >> [email protected] said: >> >>> Presumably a timing antenna would block low elevation signals to reduce >>> multipath. >>> >> >> Maybe, but there is a software aspect to the filter. You get to select >> the >> elevation angle. >> >> I don't remember seeing any specs about the filtering angles of various >> antennas. Has anybody seen something like that? >> >> >> > ______________________________**_________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/** > mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
