Working on a 5061 that I can actually see the beam current on. Looking at the manual it says to inject a frequency and there are several possible in the 50 KHz range. But it never says the drive level of the signal to use. Since this was fairly vintage equipment I might assume the coil was driven heavily. When I drive the coil at 3 or more dbm. I see the beam current go down. Is the adjustment done by actually driving the beam current down then adjusting the frequency for a slight rise? Or is it as the book says it should just be a rise from the steady state current? Just my luck the tek gen I am using has a band switch at 50 KHz splitting the possible Zeeman frequencies of interest. Lastly I stumbled into a document on C-field adjustment from HP vol 21_34 must be 1967. It suggests the better Zeeman frequency is something like 38 KHz instead of 53.53KHz. If I use 38 Khz I do see the rise. Thanks Paul WB8TSL