Gary, WB9JPS wrote:

I built a noise source as described by Bill Sabin, W0IYH in QST (1995)
and EMRFD. Works fine, but now it's time for calibration. Chatting with
Bill, he reinforces the notion that the best way to go is comparison
with another calibrated source, or a direct measurement with a
calibrated noise figure test set. NoiseCom used to provide this service
to hams for $50, but now they claim they have dropped that offer (it's
about $600, now). So my question is, is there anyone in the SF Bay
Area (I live in Livermore) who might be able to help? If someone owns a
source or test set, perhaps we could get together. I'm open to other
suggestions, too.

FYI, this is primarily for testing HF rcvr performance. I'm building an
R2-style DC rcvr, and it's turned into a nice research and education
project, so I go a bit overboard sometimes, but it sure is fun. I'm
also using an IQPro DDS VFO. I wrote a couple reports on its
performance that are up on the AA0ZZ website.

This is my first post to this group. There seem to be a lot of talented
folks lurking out there... Thanks in advance for any help.

73,
Gary, WB9JPS

For very low noise frequencies, perhaps you could use a pseudo-random
sequence generator made from fast logic clocked at say a hundred MHz, and
calculate what the "noise" power spectral density in the output signal is.
My only other suggestion is if you can make a 50 Ohm resistive terminator
on the end a teflon cable that will go into an oven, then you can just
measure the noise temperature directly... as long as you don't want an ENR
over 3dB.

Chris