"Richard" wrote in message
...
Went into a shop today and tried a small (5" x 3"x 3/4") PLL AM/FM
portable.
Tuned to a local AM station. Audio excellent for the size of speaker.
Tuned
up 9Khz and station still there, very much audible, with a bit of
splatter.
Tuned up18Khz from station, station still audible, but much slatter. Gosh,
they make the AM filters wide these days don't they in your pocket
portable!

What leads you to believe there are ANY filters in the radio? Sounds like
the BW obtainable easily within the IF and no lumped filters at all.

Dale W4OP