Please forgive my ignorance, but I don't understand what a
"noise head" is. Are you trying to build a noise generator? If
so, for what bands? FWIW, I found out many years ago that a very
inexpensive Zener diode makes a wonderful noise generator. I
built mine for my 144 MHz SSB/CW station. If you use the older
HP 342, more current HP8970A and some other Noise Figure Meters
the source of noise for tests is not integral to the Noise
Figure Meter. Rather a separate module containing a Noise Diode
is used. This allows you to connect the Noise Source directly to
the DUT (Device Under Test). In many labs techs and engineers
call the Noise Source a Noise Head as when it is attached to the
Noise Figure Meter there is a cable from the Meter to the Noise
Source which supplies power. It looks somewhat like a snake with
an enlarged head. Noise Sources (aka Heads) can use either a
vacuum tube diode or a solid state diode to generate the Excess
Noise for testing. The older HP342 was provisioned to use either
the tube or sil