I started using WWVB in 1970 in Houston working for TI using a Tracor Omega receiver. Modified it for 60 KHz and used it for 40 years. TI liked what I did and I modified quite a few for their Cal Labs in the US and Europe. Got a award and could keep all the extras. In those days TI was still in Oil exploration. Houston OCXO, on moving to Dallas buried an OCXO 20 feet in the ground, later purchased a FRK (over 3K). Two years later added temperature control and a year later a 12 bit blue Philrik DAC that I ran with a 3 MHZ Collins TCXO. Adjusted it once a year and only once did major change because I moved in 93 to Miami.
When I got my first Austron Loran C it was in parts E-13. Continued using it till the FRK died in 2010. The only bad thing was that you could hear the mechanical counter throughout the 2 story house day and night. Visitors did not appreciate it. Bert Kehren In a message dated 8/30/2018 2:03:49 PM Eastern Standard Time, kb...@n1k.org writes: Hi Same basic problem with WWVB. If you were using it as a reference, you timed your data collection to avoid the transition periods. You got both phase shifting and the amplitude took a dive. Neither one was going to help you make a precision measurement. In addition there are various weather events (terrestrial and solar) that can get into the mix. You can see blips here and there that do not correlate with the sunrise / sunset stuff. Again, not a big deal if you are manual evaluating the data to check your local Rb standard or super duper OCXO. Not a good thing for disciplining a system 24 hours a day 365 days a year. Bob > On Aug 30, 2018, at 1:54 PM, Attila Kinali <att...@kinali.ch> wrote: > > On Thu, 30 Aug 2018 12:27:12 -0400 > Bob kb8tq <kb...@n1k.org> wrote: > >> WWVB as transmitted ( = right at the input to the antenna) is a wonderfully stable signal. As soon as >> that signal hits the real world things start to degrade. Propagation between transmit and receive sites >> is a big deal, even at 60 KHz. On top of that, there is a *lot* of manmade noise at 60 KHz. The receive >> signal to noise will never be as good as you might like it to be …. > > I don't know about WWVB, but for DCF77 it's known that sunrise/sunset > causes a phase shift of several 100µs at even moderate distances > (like ~500km). Unfortunately I don't have any measurements at hand. > > > Attila Kinali > > -- > It is upon moral qualities that a society is ultimately founded. All > the prosperity and technological sophistication in the world is of no > use without that foundation. > -- Miss Matheson, The Diamond Age, Neal Stephenson > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
