> I really don't know the answer but maybe you could use a spectrum analyzer
> and a noise source. This will not tell you the impedance but you should be
> able to improve your circuit by trial and error. It may also show you any
> resonances in band, and noise peaks. A dense 'fence rail' signal may
> replace the noise generator and make the noise floor easier to see on the
> specan when you tweak the circuit.

Well, I have been developing a sort of a theory of operation when working
with analogue circuits:  Never use trial and error where calculations will
do the job.  So, I admit that I don't particularly like the idea of using
trial and error to solve this problem.

Aside from that, I didn't list the noise figure meter because I didn't think
it was relevant.  The problem I've had with it, though, is it measures
consistently higher than I expect.

For example: I have an antenna pre-amp with a rated NF of 0.5dB.  It has
50-ohm in and 50-ohm out ports.  When I hook it up to the NF meter, (which I
have calibrated using a noise source and the same 2 cables off the noise
source, only with a F-BNC to F-BNC connector, that I use with the antenna
pre-amp) It gives me 11dB or so.  Hardly an acceptable error.

It's primarily for that reason that I didn't mention the NF meter.

Anyways, got any clues on that one?

--Brendan

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