Piston Attenuator?

[Somebody]

I'm seeking tutorial and /or building instructions for a piston
attenuator which is a short waveguide operating well below
cut-off and is capable of an easily calibrated (by mechanical vernier)
attenuation factor.


AIUI, these were commonly used in valved signal generators.
Any info anywhere?

 

[Baron]

Somebody Inscribed thus:

I'm seeking tutorial and /or building instructions for a piston
attenuator which is a short waveguide operating well below
cut-off and is capable of an easily calibrated (by mechanical vernier)
attenuation factor.


AIUI, these were commonly used in valved signal generators.
Any info anywhere?

Some of the "Marconi" sig gens used those attenuators.

 

[Somebody]

Any info anywhere?

Answering my own question ...

http://www.royalsignals.org.uk/refEMERs/TelsA014.pdf