On 11 Oct 2005 06:00:50 -0700, "Tim Shoppa"
wrote:

AM wide 12-16khz
Am narrow 6-10khz

Maybe it's my aging male ears but I've never heard an AM transmission
where a 10kHz filter was needed or even desirable. Whenever I switch
on the wider filter I just hear more hiss and static, and no more
fidelity.

I can hear a small difference between 6kHz, 8kHz, and 10kHz with local
AM BCB stations. My preference has always been to abhor hiss so I tend
to go towards the narrower side. I don't think my ears are as
sensitive to hiss as when I was younger but it still bothers me
especially with extended listening.

That is because most AM broadcast station use brick wall filters at
around 4-5khz. Use to be a time back in the analog days the roll off
was both higher and gentler. Of course the Beach Boys surf music
was current then.

I also listed two AM filters for that reason. Completeness only.
Though some of the 75M AM window folks (3885khz) insist that
a wide filter is useful.

I am told that the 16kc wide filter on my R-390A was used largely for
when multiple channels were being multiplexed (e.g. multi-RTTY or
multi-voice channels).

That may be but AM used ot be much better fidelity at one time.

Allison
KB!GMX