Steve Kavanagh wrote:
"Jim" wrote in message ...

It has been a couple of years since I have done a noise figure measurement
so my brain may be a bit rusty, but I don't see anything wrong with this.

Thanks, Jim. I thought I had it right but did want a check from
someone with more experience in this field.

In fact, if you had a calibrated noise source, this is one of the 'official'
methods of measuring noise figure.

Ahhh...and therein lies the real problem for most hams. It just
occurred to me that there might be another solution to this (at least
at HF), which could be to generate noise at an accurately calibrated
level (as accurate as the power supply voltage) using a pseudo-random
digital signal.

You might find Terry Ritter's work on getting a good noise source to
be of at least a bit (ahem!) of interest:

http://www.ciphersbyritter.com/NEWS5/FMRNG.HTM

There are lots of other hits in Google for a search on
'calibrated "pseudo random" noise'
(without the outer single quotes).

It's hard to generate good noise, and at least as hard to find it.

--
Mike Andrews

Tired old sysadmin