[time-nuts] HP5065B !!!

Magnus Danielson magnus at rubidium.dyndns.org
Wed May 1 09:00:49 EDT 2013

On 04/29/2013 11:19 PM, EWKehren at aol.com wrote:
> I am still sitting here trying to figure out the purpose  of posting the
> article on laser diode pumping of the Rb. One look at the data  and it is
> clear that Corby’s work far surpasses the data shown in the paper. All  it does
> is distract from Corb’s accomplishments.

You are over-reacting. Common thread is really cleaner pumping action. 
Providing better filter or other pumping source is among the same range 
of improvements. It is not to dismiss Corbys work, rather thinking about 
the same basic approach, but implemented in another way.

What I think is interesting is that it could point to the problem with 
maintaining the filter cell aligned with the lamp cell, which in itself 
is an approximation of a filter anyway. I have not seen any rubidium 
which automatically steer this alignment.

> Lets be clear, Corby has opened
> the door of H Maser performance for those that have a HP 5065A. Not all work
> is  done but a giant step has been accomplished, the challenge now is to
> continue  the work. In simple terms it gets down to keep the A/V slope from
> turning  upward. Work is going on off list to address some of the issues and
> maybe some  one is willing to contribute. But what the list at a whole can do
> is contribute  data as to HP 5065A performance. There are quite a few 5065A’s
> out there but  very little data besides HP spec. To better tackle the
> flattening of the curve,  aging, temperature sensitivity, barometric pressure
> sensitivity and even  humidity sensitivity has to be understood. It is
> unrealistic to get past 1 E-13  unless this is understood and compensated for. Also
> some of these parameters  will vary from unit to unit and some degree of
> tailoring to a particular unit  has to be considered in the design. Some tests
> have to be done by those members  that have access to a Maser.
> Also Corby  found out that units with older A3 modules did not get the
> performance boost but  replacement of A3 did get the super performance. That
> confirms my suspicion that  there is room for work on frequency generation. PRS
> 10 does a direct  frequency generation. Somehow using the  step recovery
> diode as a mixer obviously works but is it optimum, or is there a  better way
> to generate the resonator frequency? What is key to get the best  signal and
> S/N ratio?

Locking a YIG? See HP5071A paper for that purpose.

> When previously mentioning aging control, concern was  voiced as to getting
> in to the HP 5065A. Corby’s work gets to the hart of the  unit, the RVFR,
> but Corby has gone four for four.  Adding control will only move the two C
> field wires to the analog board and using 30 mA from the unit. Unit can
> easily  restored to its original condition as far as frequency control is
> concerned.
> Obviously the RVFR is the big differentiator in the  HP5065A and I know of
> no commercially available unit that even gets close but  once the work is
> complete a look at a FRK may be in order, I doubt it will ever  be as good,
> but there is room for a filter and the physics part is considerable  larger
> than today’s units.  Some  other units may be using a filter but the physics
> package is so small that  compromises had to be made and the goal was more
> cost than ultimate performance.
> It is up to the list to turn this in to a Maser like  performance with out
> mortgaging your home.

If I get more details how I should modify my HP5065As I would consider it.


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