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Date: Thu, 3 Dec 2015 15:10:32 +0000
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From: Andy Talbot <andy.g4jnt@gmail.com>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Decode EbNaut and thrash a PC
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Status: O

I don't know that model - but with an HP tag it's likely to be one of
the 'good ones' .

In direct answer to your question, nothing will compare with Caesium -
although I don't think you really meant that :-)   Cs is a standard in
its own right, not something you can lock.  Unless you have a hydrogen
maser perhaps? (I suppose you could try using that to control the
Zeeman line magnetic field compensation - but you'd have to use a PLL
time constant of a few decades or centuries to do it properly!)

It is unlikely to be as good as a GPS disciplined Rb reference, but
even that would only be near-perfect if the time constant were made
long enough and it didn't use a frequency locked loop creating  steps
to correct as certain well known GPSDO designs do.

For a look at the state of the art in amateur timekeeping, this site
takes some beating http://leapsecond.com/time-nuts.htm

Andy


On 3 December 2015 at 14:52, Warren Ziegler <wd2xgj@gmail.com> wrote:
> Andy, Paul,
>
>      How does the HP Z3816A rate for short term stability compared to
> caesium/rubidium based GPSDOs?
>
> Thanks
> Warren
>
>
>
> On Thu, Dec 3, 2015 at 9:39 AM, Paul Nicholson <vlf0403@abelian.org> wrote:
>>
>> Edgar wrote:
>>
>>> why is a GPSDO better than using just a Rubidium
>>> Oscillator for EbNaut?
>>
>> If you have a rubidium oscillator, then use it.  But if
>> buying, then I'd suggest a GPSDO because they're often
>> cheaper, you don't have to worry about calibration, and
>> it also gives you a PPS for your soundcard and the UT for
>> your PC.
>>
>> VO1NA 2015-12-02/03 8K19A 1S 25C QRO
>>
>>  start  Eb/N0  BER    rank
>>
>>  21:00   11.5   4.6%  0
>>  21:30   14.9   0.6%  0
>>  22:00    2.5  27.4%  0
>>  22:30   10.8   5.8%  0
>>  23:00   15.4   0.4%  0
>>  23:30   13.2   2.0%  0
>>  00:00   12.1   3.5%  0
>>  00:30   14.2   1.0%  0
>>  01:00   13.1   2.1%  0
>>  01:30   14.4   0.9%  0
>>  02:00   14.3   1.0%  0
>>  02:30    4.5  22.5%  0
>>  03:00   15.6   0.3%  0
>>  03:30   12.8   2.5%  0
>>  04:00   12.4   3.1%  0
>>  04:30    6.3  17.7%  0
>>  05:00   13.7   1.5%  0
>>  05:30    5.5  19.9%  0
>>  06:30   11.4   4.8%  0
>>  07:00    9.2   9.7%  0
>>  07:30   10.9   5.8%  0
>>  08:00    8.1  12.6%  0
>>
>> Only one missing, 06:00
>> --
>> Paul Nicholson
>> --
>>
>
>
>
> --
> 73 Warren K2ORS
>                 WD2XGJ
>                 WD2XSH/23
>                 WE2XEB/2
>                 WE2XGR/1
>