Hi If you want delay ( hardware delay and not propagation), calibrating a SDR should not be to nutty. Some boards ( the Lime SDR comes to mind) will generate a signal as well as receive one. That could be piped into a scope to make the measurement fairly easy. Once you know what is going into the receiver and what is coming out, it’s just twiddling the knobs ….
Bob > On May 5, 2018, at 5:50 AM, Dana Whitlow <k8yumdoo...@gmail.com> wrote: > > Hal, > > Some SDRs can tune that low and should provide a means to determine > if noise is really the problem as well as give some clues as to the > character > of said noise. But they are much less likely to help with delay > determination, > unless you can figure out a practical way to ascertain the latency in both > the > SDR's HW and its SW. The latter component will also vary considerable > depending on what computer you are using with the SDR, as well as with > random variations due to the vagrancy of typical operating systems. > > I recently did a crude delay estimation for WWV (not WWVB) using my > Sony ICF-2010 receiver, a 2-channel DSO, and an Adafruit "Ultimate GPS" > module's PPS output. The combined (receiver + propagation) delay was > very close to 5 msec in Kerrville, TX. The precision was mostly limited by > my inability to decide precisely where each WWV tick started on the 'scope's > display due to distortion arising from multipath and the receiver's > filters. > The actual received waveform varied considerably from second to second. > > Dana > > > On Sat, May 5, 2018 at 3:08 AM, Hal Murray <hmur...@megapathdsl.net> wrote: > >> Review/background: I have an UltraLink 333 WWVB receiver. It didn't >> work. >> Several weeks ago. a discussion here mentioned that the phone cable >> between >> the main box and antenna needs to be straight through rather than the >> typical >> reversed. That was my problem. With the correct cable, the meter shows >> signal and bounces around such that with practice, I could probably read >> the >> bit pattern. But it didn't lock up. >> >> That was several weeks ago. I left it running. When I looked last night, >> it >> had figured out that it is 2018. I wasn't watching or monitoring, so I >> don't >> know how long it took. >> >> I assume the problem is noise. Is there any simple way to measure the >> noise >> around 60 KHz? How about not so simple? >> >> Extra credit for a way that others nuts can reproduce so we can compare >> the >> noise at my location with other locations. >> >> Can any audio cards be pushed that high? I see sample rates of 192K, but >> I >> don't know if that is useful. >> >> I'd also like to measure the propagation delays on WWV so a setup for HF >> that >> also works down to 60 KHz would be interesting. >> >> ---------- >> >> The UltraLink documentation says the display has a slot for a C or H. The >> C is for Colorado and the H is for Hawaii. Did WWVH have a low frequency >> transmitter many years ago? The NIST history of WWVH doesn't mention it. >> >> My guess is a cut+paste from a version that listened to WWV/WWVH. >> >> >> >> -- >> These are my opinions. I hate spam. >> >> >> >> _______________________________________________ >> 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. _______________________________________________ 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.