[AMRadio] AM Transmitter "quality"

Larry Szendrei ne1s at securespeed.us
Wed Sep 16 10:38:19 EDT 2009

Jim W4ENE wrote:

> It is the sudden cutoff that the ear dislikes.
> I point out the my old 51J4 sound pretty nice if
> the mechanical filter is kicked out.  Why?  Not
> only because of the increased bandwidth of the
> I.F.  but rather because the shape of the top of
> that filtering system is so rounded.  The cutoff of
> the audio frequencies is quite gentle.  Not all
> that wide, but the descent into the stopband is
> pretty gentle.

Very true. My R390 sounds so much better that my R390A when receiving a
good-quality AM signal at any given position of the bandwidth switch
appropriate for AM reception, and I've always attributed it to this.


Pay a visit to my amateur radio web page at:

More information about the AMRadio mailing list

This page last updated 23 Feb 2018.