These screen-shots have been taken using osmocom_fft, with my USRP-B100 and WBX daughterboard connected the discone antenna in my loft. My preamp is set for 0dB gain, the USRP gain is set to a total of 43dB which is about as high as I tend to set it in order to avoid intermod.
The first few pictures are with my KX3 in its normal position with its normal cable connections, in its normal configuration, set to 7.080Mhz. The cables are smothered in #61 ferrite.
Firstly a 8Mhz spectrum capture (below) shows a fairly high noise floor due to the bandwidth and a faint trace of the sproggy (in the centre), but some other signals towards the upper end of the spectrum, probably TETRA stuff or similar.
Next, the same scenario, but with 125kHz sample-rate/bandwidth to drop the noise floor.
The next picture is with the KX3 disconnected from everything, but sat in the same location.
The next picture is with the KX3 relocated to the kitchen, about 30 ft away from it's operating position. Both of these locations are roughly equidistant from the discone antenna in the loft, which is about 30ft away.
This time, I have two turns (they just fit) of the 2.5mm to 3.5mm adapter cable around the mix #61 ferrite toroid. The peak hold is left from the last shot, so we can see the improvement.
So far, I've found spurs on (some of) the 10th, 20th, 40th, 55th, 75th and 100th harmonics of various VFO frequencies. With my VFO on 21.25Mhz, I'm getting an S-band spur on the 100th harmonic at 2.125GHz.