[time-nuts] WWVB: measuring local 60 KHz noise
Bob kb8tq
kb8tq at n1k.org
Sat May 5 09:57:12 EDT 2018
Hi
Even if you get the 60 KHz process working, a $20 GPS module ( or maybe $50) will
do a much better job. That’s not saying *don’t* do the WWVB stuff. Just realize it’s
limitations. A second limitation is that the new phase modulation process makes
comparison a bit more complex.
60 KHz noise can be measured with any of a number of SDR’s that tune down there.
An RTL-SDR probably isn’t ideal, but there are a lot of sub $200 devices that will do
very well.
Once you have a tuner you need a “standard” antenna (if this is for noise). Some sort
of single turn loop is probably the best bet. Assuming the input to the SDR comes
pre-calibrated you are ready to go. If it’s not calibrated you will need to squirt a test
tone of known level in at 60 KHz to calibrate it ( likely a one time thing).
60 KHz reception is a bit iffy these days. The low cost world *loves* 60KHz as a
switcher frequency. It only takes one of them near your reception site to mess things
up. The E-field probe vs loop debate has been going on for at least a century by now.
I’d go with some sort of loop. With a proper location, either can work well.
Lots of fun ….
Bob
> On May 5, 2018, at 9:17 AM, Ulrich Rohde via time-nuts <time-nuts at febo.com> wrote:
>
>
> I am trying to use the 60 KHz for synchronization of a Rb receiver. The local NJ noise and the signal in dBuV are about the same with an active antenna, electric field. A better solution might be a ferrite selective antenna, H field , if I find one.
>
> 73 de N1UL
>
>
> In a message dated 5/5/2018 4:09:25 AM Eastern Standard Time, hmurray at megapathdsl.net writes:
>
>
> 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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