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From: whit@milton.u.washington.edu (John Whitmore)
Newsgroups: rec.radio.amateur.misc,rec.radio.amateur.packet,rec.radio.swap,rec.radio.cb,misc.forsale,ne.forsale,sci.electronics
Subject: Re: TRF Receiver
Message-ID: <1991Apr12.020538.11271@milton.u.washington.edu>
Date: 12 Apr 91 02:05:38 GMT
References: <1991Apr9.124118.27031@mlb.semi.harris.com> <1991Apr9.220744.4049@milton.u.washington.edu> <3106@ksr.com>
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Organization: University of Washington, Seattle
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In article <3106@ksr.com> jfw@ksr.com (John F. Woods) writes:
>In <1991Apr9.220744.4049@milton.u.washington.edu> whit@milton.u.washington.edu (John Whitmore) writes:
>>In article <1991Apr9.124118.27031@mlb.semi.harris.com> rps@sunman.mlb.semi.harris.com (Ray Sumperyl) writes:
>>> Can anybody supply me with a schematic for a tube TRF receiver?

>>	No such devices have been built by THAT name in most of a century.

>As for no one building a TRF receiver in most of a century, check out the
>Ferranti ZN414 AM Receiver chip 

	Okay, I guess I was a little strong on that statement; what
I really meant was that TRF receivers usually show up as little glue
components (like in a garage door opener) rather than as a 'receiver'.
Yes, there IS a place for tuned RF receivers, but conversion is
the norm nowadays (and has been for quite a few years).  TRF works
best at low frequency (where the Q of an LC circuit offers adequate
selectivity), and its only real advantage (cost) has rather been
taken away by the cheap ceramic IF filters in use nowadays.

	John Whitmore