"Len Over 21" wrote in message
...

On most modern HF transceivers, the 3rd harmonic has the strongest
content of RF. The 3rd harmonic of 3.5 to 4.0 MHz is 10.5 to 12 MHz
and there aren't many "ham listening frequencies" there, are there?

For most modulated sine waves, the 3rd harmonic is usually the strongest
*harmonic* although it depends upon several factors. Generally, the odd
harmonic components add and the negative components subtract with modulated
sine waves. Having said that, most modern rigs that produce FCC quality
signals will filter such harmonics several 10's of dB rendering reception
almost impossible except in the near field. I thought I needed to correct
this BS, that emanates from someone who claims to understand modern amateur
technology theory. Hams transmitting signals of any significance on 12MHz
will not be hams for long.

de KR4AJ