[time-nuts] HP5071

[Magnus Danielson]

Hi,

On 05/22/2016 12:11 AM, Richard (Rick) Karlquist wrote:
>
>
> On 5/21/2016 11:25 AM, Attila Kinali wrote:
>
>> I'd give a lot to read the design documents of the 5071.
>> There must be a lot of knowhow and techniques in them.
>
> Read papers by me and my colleagues at the 1992 Frequency
> Control Symposium.  There is nothing else in the public
> domain.
>>
>>
>> What reference did you use to measure its absolute accuracy?
>> Did you have access to the NIST standards?
>>
>>             Attila Kinali
>
> At that time, HP had an ensemble of 5061B's that they
> compared to LORAN and it was somehow traceable to NIST.
> It was claimed to be the most accurate clock on the
> west coast at the time.
>
> Also, one of the first pilot production units was
> actually taken to Boulder and compared directly with
> NIST's frequency reference.  I remember that it was
> off by a few parts in 10^13, after correcting for
> the gravitation effect of Boulder at 5000 ft vs
> Santa Clara at sea level.
>
> Over time, customers like NIST and the Naval Observatory
> accumulated data on 5071A's to establish their accuracy.
> At one time, 85% of the weight of the TAI (International
> Atomic Timescale) consisted of 5071A's. Jack Kusters said
> that, as a group, the 5071A's were accurate to around
> 10^-14, because there were no significant systematic errors.
> Hard to argue with that.

Never the less NIST and USNO keeps them in temperature and humidity 
stabilized environment with well stabilized power. Just to keep such 
systematics out of major harm.

Cheers,
Magnus