On Wed, 29 Oct 2014, William Sommerwerck wrote:

"Ian Jackson" wrote in message ...
I'm pretty sure that the local oscillator nearly always runs 10.7MHz HIGHER
than the radio signal.

Precisely If it were lower, you'd greatly increase the possibility of
images.

Isn't it more precisely, that by putting the LO higher, the image falls
where fewer strong signals are?

You don't want images to be below the FM broadcast band, then you end up
with TV stations 2 through 6. But above the FM broadcast band, you get a
decent stretch of aero band, amateur radio, public service, weather.
Channel 7 doesn't start until somewhere above all that.

Michael