> Le 5 sept. 2017 à 16:17, Bob kb8tq <[email protected]> a écrit : > > Hi > > > >> On Sep 5, 2017, at 6:06 AM, Hal Murray <[email protected]> wrote: >> >> >> Clay Autery <[email protected]> said: >>> I will use something better than RG-59 or RG-6 (even if it is only "better" >>> in my opinion). >> >> Crazy thought department. Can you also run a parallel run of RG-6 and run >> some tests to see if you can measure the difference? > > There is pretty much no experiment you could run that would show a difference > between the two. With a normal GPS, the “front end” of the radio is in the > antenna. The > filtering and RF amplification there determine a lot of things. The cable is > just a > chunk of wire in the middle of the system.
Agreed. I tried to see if there was any difference in the signal quality reported by Motorola UT+ and U-Blox Neo 6M (not timing grade but has a good 1PPS) over 30m of 2 different cable types. I only had RG58(75 Ohm) and RG174(50 Ohm) . I used the signal quality graphics of the respective manufacturers utilities winoncore12 and u-center. There was very little visible difference in the levels and reported resolved positions were as in the same ball park ( I never get exact replication after surveys ). Neither was there any significant difference in the 1PPS signal. I only have a 2 channel scope so had to measure each seperateley against a standard (PRS10). The receivers 1PPS quantization swamps the difference in the cable delay (which I was able to differentiate when measured separately). It make sense as the GPS signals are very weak and the receivers are good at getting data out, so just throwing in a bit of extra attenuation and noise doesn’t phase them at all. I was thinking of doing a test with just a twisted pair…. > > Bob > > >> >> >> -- >> These are my opinions. I hate spam. >> >> >> >> _______________________________________________ >> 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. "The power of accurate observation is commonly called cynicism by those who have not got it. » George Bernard Shaw _______________________________________________ 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.
