Jimmie wrote:
"I am trying to find data that will let me calculate the power from just
knowing the DC voltage output from the RF body."

DC load is the microammeter itself. My instruction book for the Model 43
gives the replacement meter part no. as: 2080-002. I don`t find the
meter`s sensitivity or resistance. These might be determined from a good
meter. The meter is calibrated in watts so the scale is not a straight
line function of volts or amps. Meter characteristics for your
particular model? Bird may be willing to tell you. They have a number of
application notes and data sheets available for the asking. Their
address is given as:
Bird Electronic Corporation
30303 Aurora Road
Cleveland (Solon) Ohio 44139-2794

Best regards, Richard Harrison, KB5WZI