[time-nuts] True to there word. - Fancy WWVB

J. Forster jfor at quik.com
Tue Feb 9 01:49:39 UTC 2010


I was using a HP 105B and 117A before the Austron 2100F and still have
them. From what I remember, the diurnal shift was not repeatable.

By looking at an output from the 117A and syncing the 'scope to the 105B,
I could assess the quality of the signal pretty well. Sometimes it was
stable, sometimes it was jittering all over the place by a cycle or more.

Bottom line is, IMO, WWVB is no substitute for LORAN.

I'm still hoping that the european chains will be usable.

YMMV,

-John

================


> Hi
>
> Yes indeed, you need to be sure you don't get a cycle slip. That's not
> trivial when the signal goes to zero while moving phase.
>
> There I think you need to depend on something like a reasonable OCXO and a
> long time constant loop. That brings in other problems. I assume that you
> are going to have to train your loop to "expect" the ID shifts and time
> markers. Again, they are predictable. It's just software ....
>
> More or less:
>
> Take all of the things you can compute about the signal and feed them in.
> Lock the "computed" signal against the received signal. Way less complex
> than what they do with GPS. Since it's all *very* slow, a beater PC can
> easily keep up with all the adjustment math.
>
> Bob
>
>
> On Feb 8, 2010, at 8:28 PM, J. Forster wrote:
>
>> If you track for a day, and draw a straight line throught the diurnal
>> shift, you can easily see a frequency drift of 45 degrees. That's 1/8
>> cycle of 60 KHz or about 2 uS. So 2x 10 E-6 out of 10 E5, so you can see
>> 2
>> x 10 E-11 in a day.
>>
>> ASSUMING the lock does not break.
>>
>> -John
>>
>> ===================
>>
>>
>>
>>> Hi
>>>
>>> People rarely want to use WWVB mobile. The location of the transmitter
>>> and
>>> receiver can be looked up on a map. The time of sunrise at both
>>> locations
>>> should be something that could be calculated.
>>>
>>> Assuming you are willing to put up with all of that, you should be able
>>> to
>>> do a first order correction on the shifts. The question obviously is -
>>> just how good would the net result be? Is it a 5:1 sort of thing or do
>>> you
>>> get a couple of orders of magnitude?
>>>
>>> Bob
>>>
>>> On Feb 8, 2010, at 6:40 PM, J. Forster wrote:
>>>
>>>> Yes, but WWVB is a PITA to use (because of the diurnal shifts)
>>>> compared
>>>> to
>>>> LORAN.
>>>>
>>>> -John
>>>>
>>>> ===============
>>>>
>>>>
>>>>> Hi
>>>>>
>>>>> WWVB is pretty safe. When they do a cost/benefit thing on these
>>>>> services,
>>>>> they take a look at how many taxpayers are using the service as
>>>>> intended.
>>>>> The "mission" of WWWVB is to put out time signals. There are a *lot*
>>>>> of
>>>>> taxpayers with WWVB "atomic clocks" on their walls.
>>>>>
>>>>> Bob
>>>>>
>>>>> -----Original Message-----
>>>>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]
>>>>> On
>>>>> Behalf Of Don Henderickx
>>>>> Sent: Monday, February 08, 2010 4:07 PM
>>>>> To: Discussion of precise time and frequency measurement
>>>>> Subject: [time-nuts] True to there word.
>>>>>
>>>>> The lights went out (actually red) on my Austron 2100 r this morning.
>>>>> (whats  next WWVB ?)
>>>>> Don H
>>>>>
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-nuts at 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 at 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 at 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 at 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 at 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 at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>





More information about the time-nuts mailing list