Made some measurements on a 5065A optical unit. -There are 3 layers in the magnetic shield. -There is about 1/8" of insulation between the outer and middle, and between the middle and inner shields. -The C-field winding is wound on a cardboard form that fits tightly into the inner shield. -There is almost 1/2" of foamed insulation between the C-field winding and the cell and oven forms and windings.
Per Poul-Hennings data a 3.25 deg C change of the outer shield will result in a 1 deg C change in the C-field coil. This equates to a 3.4X10-14 frequency shift when not using active current drive. If the outer shield is actively held to plus/minus 1 deg C then the shift will be held within plus/minus 1.05X10-14 as long as the ambient temperature stays within the regulating range of the PC liquid cooler. Cheers, Corby _______________________________________________ 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.
