I think you're talking about something else, that hasn't got much to do with original issue, if anything at all.
Also the cards may go up to 2800mhz (no idea where you got that from) but already at 2400mhz similar issues to those in low band appear within normal range.
The card could scan and detect transmission from my wifi router, the frequency was incorrectly detected and it showed two more harmonics at +several dozen mhz up...
From 900mhz up to 2350mhz everything looks good, and harmonics below 900mhz appear on both polarizations. How they are shown depends mainly on scanning procedure, FFT window is shown as spectrum inverted, maybe sweep method would show realistic plot, which is just as s-band wrote freq/3, freq/5 etc.
It is just a matter of setting blindscan window center freq the same as suspected harmonic center freq and then it is shown in plot.
Using wifi router in 2250-2350 mhz range and doing more scanning attempts as with above described procedure i could confirm the card sees 3rd 5th and 7th harmonic response
