In article ,
"Stan Shankman" wrote:

can anyone say if it is possible to add option-002
(the frequency doubler option)? Can such parts be obtained - perhaps from a
dead unit? Or am I better off just finding a unit that has the doubler
option already installed and parting with my current unit?

Stan-

I recall seeing that discussion some time back. Someone mentioned using
an external HP Frequency Doubler 11690A. This is a small device with
male and female BNC connectors.

I found the 11690A Operating And Service Manual somewhere, possibly at
the HP site. It contains a graph of conversion loss for different
frequencies vs input level. Internal construction details are shown.

At the time, I asked if anyone knew if you could use the internal parts
of the 11690A to add option-002 to the 8640B, but did not get a response.

Fred
K4DII