I have run 2 Tbolts from thee same antenna in to my Tracor and see the corrections are in no way correlated.Bert Kehren
Sent from my Galaxy Tab® A -------- Original message --------From: Florian Teply <use...@teply.info> Date: 4/10/18 7:00 AM (GMT-05:00) To: time-nuts@febo.com Subject: Re: [time-nuts] Dual GPSDO - any advantage? Am Tue, 10 Apr 2018 17:43:25 +1200 schrieb donald collie <donaldbcol...@gmail.com>: > I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an > error!] They are stated as being new, and use a Trimball dual oven > OCXO. I plan to run these in parallel [2 antennas, 2 feedlines, and 2 > GPSDO`s] It`s been said that a man with two watches is never happy - > unless, of course, they agree with each other ;-). Being identical > the outputs should be coherent, unless one becomes faulty [one > advantage of having two - any discrepancy and you know something must > be wrong]], but is there some crafty way I can squeeze a little more > "accuracy" out of two than if I only used one? > TIA for your > comments............................................Donald Brett > Collie ZL4GX well, my experience in that regard is very limited, not to say nonexisting, thus take the following with a grain of salt. Assuming a system with two antenna locations where one device would be fed both antennas, one could potentially employ some extra correction based on extra knowledge from these two antennas. Even though the antenna location usually is known with limited accuracy (error on the order of 1m), the relative location of two antennas can be known to a much greater accurracy (order of centimetres or better). If the system can take that extra information into account, one could maybe gain some extra accuracy for the solution of time/location. For example, if the antennas are mounted 1m apart, and everything else being equal, it is a priori clear, that the calculated position for both antennas should also be 1m apart. As the signal received by both antennas should be correlated, while their respective noise contribution is not, one should gain some SNR. If on top of that time resolution of the receiver system is very high, one could even take the phase shift between signals received from both signals into account similar to the way beam steering is done with phased antenna arrays, just on receive side, again improving SNR. So far for an integrated system, where all signals arew processed in one place. Now, as I read it you'll rather have two entirely separate receiver systems. Here, depending on how it is implemented in the receivers, one could potentially still gain something extra over a single unit, but I'd bet this can only be done in postprocessing. After all, receiver A has no access to the signals as received by receiver B and vice versa, therefore the spatial relationship can not be used while deriving the timing solution. Maybe the independent position solutions could be used to correct the timing solutions after the fact. Best regards, Florian _______________________________________________ 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.