"HankG" wrote:

In my recent SWL
experience, I found that most AM signals could be detected at less than
+/-
10 khz (usually 5) from the broadcast frequency. He's on 12.172 (I
think).
My meter seems to be resting on +30. His lower sideband is unclear, being
interrupted by other powerhouse stations.

It's not easy to determine the bandwidth of a station by using a receiver.
For instance, just because you can hear "something" from a station as you
tune your receiver over a 20 kHz range doesn't mean the station is 20 kHz
wide. You have to take the bandwidth and shape factor of your receiver's
i.f. section into account. The strength of the signal will also affect what
you observe.

For instance, a steady unmodulated carrier has essentially zero bandwidth.
But if you tune across it in lsb or usb mode, you will hear the heterodyne
over at least a few kHz. That's a funtion of your receiver, not the
transmitted sugnal.

The correct way to characterize a station's bandwidth is with a spectrum
analyzer.

Art N2AH