[Elecraft] KX-1 BC interference on 20m

[Tom W8JI]

> Given a 100 KW transmitter, with 2nd harmonics 40 dB down 
> from the
> fundamental (which would be considered reasonably good 
> suppression)  is still 10 watts at the 2nd harmonic,


I'm not sure about Europe but the Amateur radio *minimum* 
standard at HF for 1500 watts is about 45dB down for any 
spurious or harmonic. While there are lower suppression 
levels at lower power, it is set at a 50 milliwatt maximum 
limit.

The USA commercial BC standard is in the -80dB range, I 
can't remember the exact amount. I just dealt with that with 
an AM BC station 100 miles from here that had a spur on 160 
meters that was in the -40dBc range.

In all cases there is an overriding regulation that says no 
matter what the level of spurious or harmonic, the unwanted 
emission cannot cause interference to a licensed service.

This doesn't prevent BC stations from violating rules, 
especially in the USA with the poor enforcement and poor 
maintenance, but the rules themselves are pretty 
strict. -40dB would be considered very very poor 
suppression.

73 Tom