[time-nuts] Spectracom 8170 grief... Watching the problem...
I just uploaded a video to YouTube of my scope display. Others have also made similar videos. You can see it at: http://www.youtube.com/watch?v=um8HxRHkkKw Pardon the fan noise. Burt, K6OQK Gang, I took a look at the WWVB signal using a 1:1 Lissajou signal the same way I do for the FMT's. Using a 10:1 scope probe I sampled off the output of the pre-amp in the 8170 and fed it into a HP-3586B tuned to 60 kHz and compared the resultant I.F. against a HP-3336A tuned to the 15625 I.F. Both the 3586B and the 3336A are GPS locked. I won't go into the nitty gritties of how I do this, but f anyone's interested they can see my FMT Methodology at: http://www.k5cm.com/k6OQK%20FMT%20NEW.htm What I saw was the phase of the WWVB signal shifting back and forth 180 Degrees coincident with the dips in the carrier. Coincidentally, this is what all of you have been telling me, but, just the same, it was interesting to watch. The duration of each shift obviously are a form of zeros, ones and place holder. I'm wondering if the code used to shift the phase is the same code as carried in the legacy system where the duration of the carrier dips corresponds to the ones and zeros, and the place holder. Burt, K6OQK Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ 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] Spectracom 8170 grief... Watching the problem...
Gang, I took a look at the WWVB signal using a 1:1 Lissajou signal the same way I do for the FMT's. Using a 10:1 scope probe I sampled off the output of the pre-amp in the 8170 and fed it into a HP-3586B tuned to 60 kHz and compared the resultant I.F. against a HP-3336A tuned to the 15625 I.F. Both the 3586B and the 3336A are GPS locked. I won't go into the nitty gritties of how I do this, but f anyone's interested they can see my FMT Methodology at: http://www.k5cm.com/k6OQK%20FMT%20NEW.htm What I saw was the phase of the WWVB signal shifting back and forth 180 Degrees coincident with the dips in the carrier. Coincidentally, this is what all of you have been telling me, but, just the same, it was interesting to watch. The duration of each shift obviously are a form of zeros, ones and place holder. I'm wondering if the code used to shift the phase is the same code as carried in the legacy system where the duration of the carrier dips corresponds to the ones and zeros, and the place holder. Burt, K6OQK Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ 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.
Re: [time-nuts] Spectracom 8170 grief... Watching the problem...
Burt Yes this has been looked at before by time-nuts and as you say it shifts. Its also documented by nist and unfortunately the AM code is nothing like the new psk code for a good reason. Better noise immunity and other things also documented. Its complex at least for me. Overall I get it but when I get to the error correction and disassembly of the message format its not so clear. Though perhaps it would be if I were building a psk decoder and that may happen later but only after the d-psk-r is really pretty complete. A by product of the d-psk-r is the psk code so its there for the taking. Regards Paul WB8TSL On Fri, Jun 14, 2013 at 8:13 PM, Burt I. Weiner b...@att.net wrote: Gang, I took a look at the WWVB signal using a 1:1 Lissajou signal the same way I do for the FMT's. Using a 10:1 scope probe I sampled off the output of the pre-amp in the 8170 and fed it into a HP-3586B tuned to 60 kHz and compared the resultant I.F. against a HP-3336A tuned to the 15625 I.F. Both the 3586B and the 3336A are GPS locked. I won't go into the nitty gritties of how I do this, but f anyone's interested they can see my FMT Methodology at: http://www.k5cm.com/k6OQK%**20FMT%20NEW.htmhttp://www.k5cm.com/k6OQK%20FMT%20NEW.htm What I saw was the phase of the WWVB signal shifting back and forth 180 Degrees coincident with the dips in the carrier. Coincidentally, this is what all of you have been telling me, but, just the same, it was interesting to watch. The duration of each shift obviously are a form of zeros, ones and place holder. I'm wondering if the code used to shift the phase is the same code as carried in the legacy system where the duration of the carrier dips corresponds to the ones and zeros, and the place holder. Burt, K6OQK Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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.
Re: [time-nuts] Spectracom 8170 grief... Watching the problem...
What I saw was the phase of the WWVB signal shifting back and forth 180 Degrees coincident with the dips in the carrier. Coincidentally, this is what all of you have been telling me, but, just the same, it was interesting to watch. The duration of each shift obviously are a form of zeros, ones and place holder. I'm wondering if the code used to shift the phase is the same code as carried in the legacy system where the duration of the carrier dips corresponds to the ones and zeros, and the place holder. Burt, K6OQK The new PM (phase modulated) WWVB format is *in addition* to the existing AM format. Consequently millions of commodity clocks and wrist watches continue to function just fine. The only instruments that break are vintage phase tracking receivers. Paul's Costas's loop project addresses those receivers. The latest preliminary version of the spec for the new PM code is here: http://www.nist.gov/pml/div688/grp40/upload/NIST-Enhanced-WWVB-Broadcast-Format-2012-12-07-3.pdf If anyone has seen a more recent version, let me know. Thanks, /tvb ___ 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.
