[SNIP]
=20
Oh, I don't know. The Heath HR-10 ham receiver, while admittedly in a =
lesser=20
league, did this on 15 and 10 meters and admitted it. I would strongly =

suspect that many of the lower end sets did this, but didn't fess-up.=20
=20

I am not sure of their rationale. Perhaps the stability of 30 MHz =
oscillator is, in practice, more than twice worse than that of a 15 MHz =
oscillator, so they preferred to work at lower frequency and take the =
second harmonic. They did not even care to filter the oscillator =
frequency so as to remove the fundamental and leave only the harmonic.

By the way I put a parallel LC circuit in series with the 20 meter RF =
input transformers, and, adjusting its for resonance around 9.6 MHz, the =
BCs disappear completely. Adjustment is quite critical and the resulting =
BCs attenuation is tremendously high.

73

Tony I0JX / K0JX