On 04/29/2013 11:19 PM, ewkeh...@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. Cheers, Magnus _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
