Hi At least in my back yard, a 6' tall tripod would be very noticeable from a number of directions. There are many others in similar situations. If I were to interpret the restrictions literally as written, an antenna that was inside the house, but visible through an open window is also a violation.
Bob On Sep 27, 2012, at 7:11 PM, [email protected] wrote: > Various comments - > > Hal mentioned SNR for the scheme I suggested. A PLL can be a coherent > demodulator of arbitrary > bandwidth. Thus the PLL at the output of the doubler can have a small > bandwidth since at that point > there is no PSK, it having been removed by the doubler. So given a stable > VCXO you can probably get down > to 1 Hz and thereby achieve a good SNR. There is a lot of stuff out there on > phase tracking receivers > that do exactly that. You know the frequency so the loop does not have to > search far and the BW can be increased > for acquisition and closed up for tracking. > > On writing reams of code - my point was that it is not required to used the > admittedly more powerful software > techniques to do this job - I noted that one reason to write reams of code is > for the fun of it, this is after all > a hobby. > > GPS Antenna Siting - > > Lets not make this so hard. Mine is at 6 ft elevation and is blocked to an > elevation angle of 20 to 30 degrees by a house > within 15 ft and a forest of trees. I have room and no restrictions but I > also have severe thunderstorms - so the house > plays lightning protect for the antenna. My T bolt tracks a Rb to better than > 1e-12 over 24 hours with no serious 10 MHz phase bumps > as plotted on a strip chart recorder. > > Sooooo - > > Put your antenna at 6 ft in back yard. Start out on a photo tripod - who is > gonna notice? > set up a t bolt at EL=5 AMU=0 Damping = 1.2 and Time Constant = 100 sec. > get the t bolt manual > get Tbolt monitor > get Lady Heather and read all that stuff. > > Run Lady Heather antenna survey (command SAS) for at least two days - you > get a map of signal level in dBc vs elevation > Reset the Tbolt elevation mask to reject anything that is shown as blocked > using the signal > level map. Likewise experiment with the AMU setting to reject the weak = poor > signals. Mine works good > with AMU all the way up to 10 as fewer good satellites are better than lots > of weak ones. > > The satellites are in high orbits so masking those below 25 degrees is OK and > the AMU sets the acceptable signal > level - at AMU 10 my setup throws out those below about 40 dBc - the strong > guys go up to 50. This is a function > of you antenna performance so some experimentation is required. > > -73 john k6iql > > > > > _______________________________________________ > 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. _______________________________________________ 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.
