I have to agree that the subjects really drifted. I am very excited about what seems like a reasonable effort to improve the 5065. Since I have one all the more interest. So I want to hear about the reflectors and concentrators and how they were added and then how the system may have been retuned to leverage the change. Have I accidently gotten on to the wrong thread?? If so can some one please point me to the correct thread? Thanks Paul WB8TSL
On Mon, Apr 29, 2013 at 6:30 PM, Bruce Griffiths <bruce.griffi...@xtra.co.nz > wrote: > Since performance improves as the bandwidth of the "lamp" spectrum > decreases its not unreasonble to suggest that a suitable laser source may > improve performance further. > > The following paper (and theoretical considerations) indicate that your > conclusions regarding the potential performance of a laser pumped rubidium > standard are incorrect. > > http://tf.boulder.nist.gov/**general/pdf/1219.pdf<http://tf.boulder.nist.gov/general/pdf/1219.pdf> > > The addition of second harmonic traps tuned to the 2nd harmonic of the > modulation frequency of the resonance interrogation signals should improve > the performance considerably. > > > Bruce > > > 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. 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? >> 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. >> Bert Kehren >> ______________________________**_________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/** >> mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >> and follow the instructions there. >> > > ______________________________**_________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/** > mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> > and follow the instructions there. > _______________________________________________ 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.