[time-nuts] cesium Zeeman frequencies

corby d dawson cdelect at juno.com
Sat Jul 19 13:47:29 EDT 2008

The Zeeman frequency is calculated by the amount of C-field current you

If you change the Zeeman then to get the unit "on frequency" you then
have to change the synthesizer frequency and the C-field current to
compensate. The amount of C-field change is too big for the front panel
knobpot so a resistor change on the A15 board is required.

The earlier 5061A current (61miiliGauss) resulted in a synthesizer
frequency of 12.6317716 Mhz giving a corresponding Zeeman frequency of

On later 5061A and B units HP decided that using a different current (76
milliGauss) that was more stable which ended up giving you 12.7317725Mhz
and 53.53Khz.

There is NO difference in the tubes C-field winding (for 5061A/B and
5071A). The current set resistor on the A15 board and the synthesizer
frequency are the only change.

Corby Dawson
Learn about VA loan programs and benefits. Click now.

More information about the time-nuts mailing list