In message , William Sommerwerck
writes
"Michael Black" wrote in message
news:alpine.LNX.2.02.1410291558180.4171@darkstar. example.org...
On Wed, 29 Oct 2014, William Sommerwerck wrote:

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?

That would depend on band allocations and transmitter power. I'm
thinking of images from within the FM band.

Given that the FM band is 20MHz, and twice 10.7 MHz is greater than
20MHz, if the LO is above the incoming signal, images would come from
stations above 107.9MHz (outside the band). If the LO were below the
incoming signal, you could have in-band images starting at 98.9MHz.

No. Taking the upper band edge as 108, 108 - 2x10.7 = 86.6 (well below
the lower band edge). This is within old US TV channel 6 - and as you
tune lower, you will hit channel 5.
--
Ian