Hi all,
i just tried to measure the Noise Figure of SA44b at its signal input. The result is about 40 dB at 1100 MHz.
The double output power method is used, not an Y-factor one; the spectrum analyzer tests a noise signal from external generator (Rohde&Schwarz SMBV100A), the level of signal at the input is known and adjusted to get the 3 dB higher result in comparison with an unperturbed noise floor when RF signal is off. The software is Spike 3.2.0; the averaging detector, power units, averaging trace were switched on. The results for power were read with enabled “Channel power”, bandwidth – 1 MHz.The generator gives a noise in 10 MHz band. The 3 dB rise in analyzer readouts was at the input power about -73 dBm/1 MHz; that gives NF=174dBm/Hz-10*log(1MHz)-73dBm/1MHz=41 dB.
The same procedure gives NF almost 20 dB for Rohde&Schwarz FSW13.
Regards, Dimitry, UA3AVR.