Re: AM radio receiver - design





As you have seen the problem is generally not the receiver, it's the noise
on the band.
Check out this site, Dallas Lankford has been working at this problem for
many years.
Reviewing his many projects will give you an education on the source of
problems and
some ways to minimize them.
I built one of his phasing unit about 13 years ago, had a lot of fun with
it. Several times
I had a situation where I nulled a station, and then by flipping a switch
I
could hear another
station on the same frequency. I think he is now 2 maybe 3 generations
past
the one I built.
http://www.kongsfjord.no/dl/dl.htm

Mike

I've seen Lankford's work. A lot of it is dubious at best. I recall he
had a "paper" where adding a lowpass filter in the audio path would
reduce fading.

Please look through the papers and on the URL I postedm and post any
dubious
material you find. Inquiring minds want to know!


The phasing schemes work if the QRM/N is local. I have a ANC-4 for
that purpose.

Phasing schemes are also helpful to null out unwanted stations on the same
frequency
Mike



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