Aah. This is a very good point about antenna location and extra satellites! In fact, it is quite possible that the location my antenna will be (outdoors but not above roof line) may have limited sight. That's very much
73 Eugene W2HX -----Original Message----- From: jimlux [mailto:[email protected]] Sent: Friday, November 26, 2010 6:48 PM To: Eugene Hertz; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] ok, newbie questions W2HX wrote: > Ahh. Very interesting explanation. So is it somewhat correct to assume (yes, > I know) that for a stationary (non-mobile) environment, these extra sats > don't make much difference? This seems to be what the explanation is saying. Depends on your antenna location and type. The extra satellites help reduce the effect of multipath. And, the overall variance of the nav/timing solution is reduced when you put more signals into the solution (e.g. a sqrt(N) sort of thing) > > Ok. So let me see. For a frequency standard for use in lab equipment, it > appears that short term, phase noise and other sources of noise are the > things to be concerned with to get better results. These seem to really be > accomplished with a good oxco. However, if I want a very accurate > time-of-day clock for long periods of time, then I need long term stability > which is where the GPS comes in. Do I have this right? Yes. > > So if I want a really souped-up freq standard for my lab, then I should > concentrate on finding the best oxco I can (which may be disciplined by the > GPS or manually occasionally calibrated to GPS), and use the best power > supply I can find. These seem to be what I should concentrate on rather > than more channels. > Yes. _______________________________________________ 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.
