On my Kenwood HF scanner, if a high power signal is received too strong, it can cause interference on other frequencies around the band, I have an attenuator switch I can use to lessen the signal overdrive... it has nothing to do with the transmitters though, simply a high power HF signal being received too strongly. My attenuator switch allows me to attenuate reception by 10 to 40 db in 4 stages.
What a pity ! Attenuate the antenna signals because just behind there is too much amplification !
I rarely use the ATTN , I can set the RF gain lower. And the ATU really tunes.
Believe me, those spurs are spurs !