Here's a link to the other pdf that I spoke of on the programming. It goes into some of the same, but it does have other info.
http://www.dd1us.de/Downloads/precise%20reference%20frequency%20rev%200_4.pd f Best, Will *********** REPLY SEPARATOR *********** On 7/13/2011 at 8:06 PM Will Matney wrote: >I think it's more in who had them and tried to calibrate them, as some of >these are actually programmed for the desired frequency. I forget which pin >that is, but I think it may show it in one of the pdfs. There's another pdf >available out there from a ham who did a lot with these, and it did show >how to program/calibrate them. > >I know a few of the guy's over in Asia like to play with these before they >sell them, so I think a lot of it's all in whom you get them from. > >Best, > >Will > >*********** REPLY SEPARATOR *********** > >On 7/13/2011 at 4:56 PM WB6BNQ wrote: > >>David, >> >>The answer to your question is quite complex. A number of factors control >the >>operation of a passive atomic resonator acting as a filter. Temperature, >pressure, >>buffer gas mixtures, external magnetic forces, coupled light excitation, >the length >>of the cavity, the interrogating external RF energy level are but some of >those >>factors. >> >>The "Atomic" nature of the filter is based upon the extremely narrow >resonance of >>electron absorption of energy which occurs at a specific frequency and is >influenced >>by the previously mentioned factors. That specific RF excitation >frequency is >>different for each element in the Periodic Table. For example the >Hydrogen Maser is >>around 1.45 GHz; the Rubidium is in the 6 Ghz range and the Cesium is in >the 9 Ghz >>range. >> >>None of the specification sheets even approach trying to answer such a >question >>directly. However, with certain qualifying assumptions, it could be >inferred from >>"certain" specs, if available, as a general idea, BUT, by no means the >complete >>answer. >> >>For example, looking at Symmetricom's XPRO Rubidium spec sheet, they give >a 10 year >>spec of ?+/-1x10e-9. The assumption is the unit was built correctly, was >adjusted >>to be precisely on frequency at its intended installation site and was >left powered >>on, in a stable atmosphere, without failures of any kind for the entire 10 >years. >>If the product truly met those assumptions and specs, then I would say, >with some >>confidence, that if you picked up a used one working properly that it >would be >>reasonable to assume after powering up and allowing it to come to a stable >>temperature (24 hours) and it indicated a locked condition that it would >be within >>1x10e-9 of the correct frequency. Unfortunately, FEI is not so forth >coming with >>their product literature, but I suspect their units are similar. >> >>Also, be aware that at least one member on this list has reported buying >two 5680A's >>from China and they were both significantly off frequency by many hertz. >Inspection >>and determination of the problem is a project in motion. This same member >has >>further stated other reports exist on the WEB of other units exhibiting >the same >>problem, although I have not seen those reports. >> >>It may prove out that the two 5680A's have a problem. It is equally >possible that >>they are deliberately offset for some specified yet unknown reason. Time >will tell. >> >>While a Cesium frequency standard is by definition and without question >accurate, >>that only applies under a narrow set of circumstances. It is possible to >miss >>adjust such a beast and that is why multiple standards labs constantly >cross check >>themselves. >> >>Remember, to error is human and machines do what we tell them ! >> >>Bill....WB6BNQ >> >> >>"Dr. David Kirkby" wrote: >> >>> If an old random 10 MHz Rubidium oscillator is working (i.e. powers up, >and >>> eventually locks), what is the maximum possible frequency error it could >have? >>> >>> Could it remained locked with an error of 1 part in 10^7, 10^8, 10^9, >10^10 etc? >>> >>> I assume there are physical limits which would simply stop it >functioning too >>> far from the correct frequency, but don't have much clue what they are. >>> >>> -- >>> A: Because it messes up the order in which people normally read text. >>> Q: Why is top-posting such a bad thing? >>> A: Top-posting. >>> Q: What is the most annoying thing in e-mail? >>> >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> >>_______________________________________________ >>time-nuts mailing list -- [email protected] >>To unsubscribe, go to >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>and follow the instructions there. >> >>__________ Information from ESET Smart Security, version of virus >signature database 5851 (20110206) __________ >> >>The message was checked by ESET Smart Security. >> >>http://www.eset.com > > > > >_______________________________________________ >time-nuts mailing list -- [email protected] >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > >__________ Information from ESET Smart Security, version of virus signature database 5851 (20110206) __________ > >The message was checked by ESET Smart Security. > >http://www.eset.com _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
