Dave, thanks for the info. I am, as I have said, money limited to the point
where most solutions won't work for me.
My counter is an HP 5328A I belive. Not the top of the line but with care it
can do a decent job. It's oscillator is the standard oven job. When I got it,
it was almost spot on but it's been a while and I'd like to reset or at least
recheck it. It's good enough that it can watch other oven oscillators drift,
such as the one in my 8657B generator. I mean, who is crazy enough to sit for
hours watching a display progress more and more slowly toward some monte carlo
frequency?
Anyway it's all in fun for me and I have no real need for this precision. And
I know how close my transceiver must be to be 'on frequency' and it certainly
is fine with no intervention.
Bob
On Saturday, January 26, 2019, 8:01:40 AM PST, DM <[email protected]>
wrote:
Bob,
Please advise the make & model of your counter, and if possible, the make &
model of the OCXO it contains, or if you have the manual, the aging spec on the
time base. It's entirely possible (probable) that the OCXO is already several
orders of magnitude better than any HF WWV broadcast. BTW, higher frequency
broadcasts are much more susceptible to atmospheric shifts than lower
frequencies. That's why WWVB at 60KHz was used for many years as a traceable
standard.
How long has it been since its last real calibration (not beating against WWV,
but properly calibrated)?
I agree with the others who have advised in favor of a GPSDO. A second approach
would be a Rubidium standard. Much more stable than a stand-alone OCXO, and
they don't need an antenna. But, you would need to be assured that it's
properly calibrated when you buy it. Ebay seller rdr-electronics sells Rb
oscillators, and I'm pretty sure those they sell are properly calibrated before
they ship them out. Good folks.
Since you live in the LA area, surely there are other hams in the area who have
the ability to properly adjust the time base in your counter. Get on the air
and ask around. Might be someone just a couple of blocks away who has all you
need.
Cheers,
Dave M
----- Original Message -----
From: "Bob Albert via time-nuts" <[email protected]>
To: "Discussion of precise time and frequency measurement"
<[email protected]>
Cc: "Bob Albert" <[email protected]>
Sent: Saturday, January 26, 2019 12:06:43 AM
Subject: Re: [time-nuts] Frequency standard
Paul, thanks for your reply.
You ask what I want to accomplish. Basically I just want to be able to
calibrate the OCXO in my counter. I don't get a good enough signal from WWV and
don't really have a proper method for adjustment.
I listen to the highest froquency WWV I can hear, and these days it's probably
only 10 MHz. I listen on a communications receiver to my counter and to WWV
beating. As I watch the S meter, the pulsing gets slower and slower as I zero
in, and at some point the pulsing is lost because the atmospheric fading masks
it. That's usually around one fade every couple of seconds, for an accuracy of
only about 1 part in 20 million. I want it somewhat better, but no way do I
need it 100 times better. If I could set it within 0.1 Hz that would be fine -
it would enable frequency measurement at 100 MHz with pretty good confidence,
less so at 500 MHz. I used to be able to hear 20 and 25 MHz from WWV but those
days are gone. Even then, the confidence level is a bit poorer than I'd like.
So maybe a GPSDO would help but it seems the cost is out of proportion to my
needs.
Bob
On Friday, January 25, 2019, 9:01:59 PM PST, paul swed <[email protected]>
wrote:
Bob
The gpsdos will be far superior to the method you are currently using. I
will guess 100-1000 times better and higher. I took a quick look at EBAY
boy there are lot of them these days. We all have our favorites. Trimbles,
HPs... But what would help is understanding your need. What do you want to
accomplish.
Regards
Paul
WB8TSL
On Fri, Jan 25, 2019 at 9:05 PM Bob Albert via time-nuts <
[email protected]> wrote:
> Please excuse my ignorance but I have been trying to improve on my
> frequency calibration.
> I have always used WWV but when I try to get really close in frequency,
> the beat and the fading are difficult to separate.
> Someone suggested I get a GPSDO to refine my 10 MHz. I looked around and
> have seen a few, mostly in the $100 range, but before I shell out fot
> something I know little about I wonder if someone can give me a short
> tutorial or at least some advice on what I need to do.
> I live in Los Angeles so I imagine signals would be reasonably strong.
> But what hardware and software do I need? I want 10 MHz to put into my
> counter or, at least, to calibrate the time base in the counter. I prefer
> the latter, since that means I won't have to receive GPS signals in order
> to measure frequency. Most of the time I don't need really accurate
> results.
> I could run an outdoor antenna if needed. What receiver ought I look
> into, how much budget do I need, and all the other questions relating to
> this subject.
> And finally, how much frequency error can I expect?
> Bob
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