Björn

> So while I'm eager to see Donald's results, I question their merit. The 5061 standards already have a very convenient Cs-Off switch right on the front panel. It is there so you get the pure 10811 performance when you need it. Use it. In fact there's lots of people run their precious 5061 in > Cs-Off mode 23.9 hours a day and just turn on the Cs once a day, or once a > week, to re-cal the oscillator. It's not there just to conserve cesium; you also get full 10811 short-term performance. Note also some 5061 have a > short/long time-constant switch which also helps you tailor the ADEV you want out of the instrument. > /tvb Very nice design by HP. For the same era design, the OSA (telecom) module made other choices. When turning off CS, they turn off power to the output module and the efc tuning circuit. So even if there is a nice and warm BVA inside - without burning CS - the standard output is not working and also its off any manual tuning. -- Björn

Hi, On 05/28/2017 11:52 AM, "Björn Gabrielsson" wrote: >> So while I'm eager to see Donald's results, I question their merit. The > 5061 standards already have a very convenient Cs-Off switch right on the > front panel. It is there so you get the pure 10811 performance when you > need it. Use it. In fact there's lots of people run their precious 5061 > in >> Cs-Off mode 23.9 hours a day and just turn on the Cs once a day, or once > a >> week, to re-cal the oscillator. It's not there just to conserve cesium; > you also get full 10811 short-term performance. Note also some 5061 have > a >> short/long time-constant switch which also helps you tailor the ADEV you > want out of the instrument. >> /tvb > > Very nice design by HP. > > For the same era design, the OSA (telecom) module made other choices. When > turning off CS, they turn off power to the output module and the efc > tuning circuit. > > So even if there is a nice and warm BVA inside - without burning CS - the > standard output is not working and also its off any manual tuning. In addition, and I consider this somewhat of a design flaw, the external voltage reference to the oscillator (pre-BVA or BVA) is also powered of, so it drift south rather than stay put. Otherwise it would have been easy to trim the oscillator for zero lock enforcement and then free-wheel on the OCXO when Cs is powered down. The OSA 3000 and 3100 cesiums are nice analog cesiums, but lacking the refinement of digitally controlled that came later. Cheers, Magnus

Though I will never see a OSA 3000, It certainly sounds like a hack could be done to obtain a Cs off reference. But then when you don't actually have one you can make comments like that. Sounds nice. Regards Paul WB8TSL On Sun, May 28, 2017 at 8:20 AM, Magnus Danielson < magnus@rubidium.dyndns.org> wrote: > Hi, > > On 05/28/2017 11:52 AM, "Björn Gabrielsson" wrote: > >> So while I'm eager to see Donald's results, I question their merit. The >>> >> 5061 standards already have a very convenient Cs-Off switch right on the >> front panel. It is there so you get the pure 10811 performance when you >> need it. Use it. In fact there's lots of people run their precious 5061 >> in >> >>> Cs-Off mode 23.9 hours a day and just turn on the Cs once a day, or once >>> >> a >> >>> week, to re-cal the oscillator. It's not there just to conserve cesium; >>> >> you also get full 10811 short-term performance. Note also some 5061 have >> a >> >>> short/long time-constant switch which also helps you tailor the ADEV you >>> >> want out of the instrument. >> >>> /tvb >>> >> >> Very nice design by HP. >> >> For the same era design, the OSA (telecom) module made other choices. When >> turning off CS, they turn off power to the output module and the efc >> tuning circuit. >> >> So even if there is a nice and warm BVA inside - without burning CS - the >> standard output is not working and also its off any manual tuning. >> > > In addition, and I consider this somewhat of a design flaw, the external > voltage reference to the oscillator (pre-BVA or BVA) is also powered of, so > it drift south rather than stay put. Otherwise it would have been easy to > trim the oscillator for zero lock enforcement and then free-wheel on the > OCXO when Cs is powered down. > > The OSA 3000 and 3100 cesiums are nice analog cesiums, but lacking the > refinement of digitally controlled that came later. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. >