> Now if the device was on one of those side peaks what would that make the > offset at 5 MHz be?. > I think something like 1 Khz divided by 9192631770. I am sure 5 MHz comes > into the calculation. > Pretty small. But may guess thats what I see. Its 44ns slow over 27 minutes > as of yesterday. > The systems been on 4 days.
Paul, 40 kHz / 9192 MHz is 4e-6, so you're obviously not locked to one of the 6 wrong peaks. 1 kHz / 9192 MHz is 1e-7, or 100 ns per second, so I don't think you're locked to one of the 2 side peaks either. A 1e-7 error translates to 0.5 Hz out of 5 MHz. 44 ns / 27 minutes time drift = 2.7e-11 frequency offset. Maybe all you need to do is adjust the C-field dial. As a quick test measure the 5061A output frequency at min C-field and max C-field to get an idea of your tuning range. HP used two different ranges on the 5061A. Or measure at each turn of the dial, as I did here: http://www.leapsecond.com/pages/hp-5065a-cfield/ If you want, perform the Zeeman calibration as described in the 5061A manual. It says "an error of 1% in the Zeeman frequency causes an error of 3.6 parts in 10^12 in the 5 MHz output". /tvb ----- Original Message ----- From: "Tom Van Baak" <t...@leapsecond.com> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Saturday, December 06, 2014 9:04 AM Subject: Re: [time-nuts] HP 5061Cs reference question Paul, There are 7 peaks total, about 40 kHz apart (on my 5061A). If you're talking about just the central peak, there are two smaller peaks on either side, about 1 kHz apart. The exact value depends on internal magnetic field, which is specific to each beam tube design. For some measurements of all the peaks, have a look at: http://leapsecond.com/pages/cspeak/ You can play with the C-field in addition to playing with peaks: http://leapsecond.com/images/cfield.gif (578 x 4610 pixels) For more details search the archives for the word Zeeman. For example: https://www.febo.com/pipermail/time-nuts/2005-April/018171.html A nice description from hp how a cesium beam standard works: http://leapsecond.com/museum/hp5062c/theory.htm /tvb ----- Original Message ----- From: "paul swed" <paulsw...@gmail.com> To: "Time-nuts" <time-nuts@febo.com> Sent: Saturday, December 06, 2014 6:11 AM Subject: [time-nuts] HP 5061Cs reference question >I have a curious question that really applies to all Cs references. > Its possible to set them on to the wrong peak. > Typically in the literature it will speak to at least 3 peaks and you want > to select the highest central peak. > However if you select the wrong peak, how much would the output frequency > be off? > I had read a tech note for the airforce that seems to indicate its pretty > easy to get on to the wrong peak. > Regards > Paul > WB8TSL _______________________________________________ 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.