[HBR] Look Ma, no I.F. cans!

[Brian Burns]

Hello All,

 

In browsing back issues of  73 magazine I came across an article on
selectivity in the April 1961 issue entitled "Take Your Pick". It's about
filters in all their various permutations. Here is the link to the on-line
back issues:

 

https://archive.org/details/73-magazine

 

It's an excellent article, and about halfway through is the description and
schematic for a "crystal coupled I.F. amplifier"---no I.F. transformers,
just crystals. The author says just add RF stage, mixer, detector, and audio
stage, and you have a "good receiver". He says the selectivity is equal to
that of a mechanical filter.

 

My only reservation is that Carl, KM1H, says that selectivity gotten with
coils and capacitors sounds better. All those super high Q crystals look
likely to ring a good deal. 

 

Cheers,

 

Brian



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