Here's more context on App Note 150 to round out the discussion on noise power and noise figure, and how to measure the NF of the SA-
"At room temperature and for a l-Hz bandwidth, kTB = -174 dBm. We know that the displayed level of noise on the analyzer changes with bandwidth. So all we need to do to determine the noise figure of our spectrum analyzer is to measure the noise power in some bandwidth, calculate the noise power that we would have measured
in a l-Hz bandwidth using lO*log(bwJbw,), and compare that to -174 dBm. For example, if we measured -110 dBm in a lo-kHz
resolution bandwidth, we would get
NF = (measured noise),m,, - l0*log(RBW/l) - kTB,_
= -110 dBm - 10*1og(10,000/1) - (-174 dBm)
= -110 - 40 + 174
= 24 dB.
Noise figure is independent of bandwidth."
Noise Figure is a function of device temperature and current flow. So there are three terms that define how much noise power is within a channel, K, T, and B. They are all physically independent parameters, and aren't correleated.
I have a good idea for us.
Measure with your 8566 the noise floor of your Cobra 148 radio, just before the detector diodes at the end of the I/F chain. Set the scan width to be 10 KHz total, and measure the peak noise at channel center.
Make the measurement with the radio off, and then turned on, with the antenna input terminated. No signal, RF gain at max CW, then post your results.
