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David · July 30th 06, 05:19 PM posted to rec.radio.shortwave

On 30 Jul 2006 09:06:34 -0700, wrote:

wrote:
snip
Except we are not talking about IF filters .The "fading" filter is at
the end of the chain, i.e. past the demod.
snip
Except this is at audio frequencies, where the component sizes are much
larger. Again, this is not at IF frequencies.

Mr. Lankford's main concept is that by using a narrow enough IF filter,
a narrow filter with with a step attenuation skirt, and by offset
tunning to
only get the carrier and the desired sideband, and with a following
suitable AF LP fitler can do wonders. It is not magic, and doesn't work

with every receiver and under every condition. In the ret of this, and
all
future posts, I will simply call it "ELPAF".

I can say is that it is a usefull technique, and will even help when
used
premium receiver like an AOR7030 or R390, the filter can really reduce
the effects of "fading". With a modest receiver like the R2000 that has

been upgraded with a suitablely narrow IF filter, the results are
impressive.
With a "marginal" receiver like the ATS909/DX398 the results are
nothing
short of amazing.

Terry

I used a similar technique with my R-390A. I'd tune one side of the
carrier and use the BFO to provide a local one. You have to back way
off on the RF gain as the 390A BFO is sort of weak.