Noise figure of XCVR2450

Hi List,

I have previously claimed on this list that I have measured a noise
figure of some 4dB on the XCVR2450. However, I probably made the
following mistake: I used a CW of 2.4GHz as signal. However,there is
spurious at 2.4GHz which I mistook for being my desired signal. The
signal generator and the USRP2 was locked so there was just a single

When I measured today I got a noise figure around 25dB. I wonder if it
can be noise from the transmitter chain which is leaking into the


I spotted in the data-sheet that to get a noise figure of 4dB a voltage
gain of 50dB is needed.

My experience has been that a voltage gain above 20dB makes the receiver
go haywire. However, I may need to review this assumption.