[time-nuts] WWVB: measuring local 60 KHz noise

Dana Whitlow k8yumdoober at gmail.com
Sat May 5 05:50:17 EDT 2018


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
of said noise.  But they are much less likely to help with delay
unless you can figure out a practical way to ascertain the latency in both
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
The actual received waveform varied considerably from second to second.


On Sat, May 5, 2018 at 3:08 AM, Hal Murray <hmurray at 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.
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