[rec.radio.swap] TRF Receiver

rps@sunman.mlb.semi.harris.com (Ray Sumperyl) (04/09/91)

 Can anybody supply me with a schematic for a tube TRF receiver?

                                        Regards,
                                         Ray S

rps@sunman.mlb.semi.harris.com

whit@milton.u.washington.edu (John Whitmore) (04/10/91)

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.  Any of the '60s vintage Radio Amateur Handbooks, though,
will have 'grid-dip meter' construction articles, and a grid
dip meter is exactly a TRF receiver (not terribly sensitive, though,
as they usually leave out the preamplification).  After mid-60's,
the grid-dip meters used MOSFETs (what's a 'grid' in a MOSFET?).

	John Whitmore

stealth@caen.engin.umich.edu (Mike Pelletier) (04/11/91)

In article <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
  [...]

Could you, Mr. Whitmore, please refrain from crossposting your article to
all of rec.radio, and could you, Mr. Sumperyl, take a look at what groups
you`re following up to and modify them so that they're appropriate?  I
mean really, who in rec.radio.cb would have a schematic for a tube TRF
reciever?

And why in misc.forsale, let alone rec.radio.cb??

--
Mike Pelletier                     |
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Computer Aided Engineering Network |           [         left blank       ]
  Usenet, UUCP, IRC and mail admin |

fiesta@cbnewsi.att.com (eric.c.beck) (04/11/91)

>  Can anybody supply me with a schematic for a tube TRF receiver?

There's an outfit called Lindsay Books in Illinois that sells lots of
vintage books.  They've got two catalogs, one focusing on machine and engines,
and the second on electronics.   Get the catalog for "old-time" electronics
books - I'm sure you'll find something in there that is exactly what you need.


			Eric Beck
			

jfw@ksr.com (John F. Woods) (04/12/91)

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.
>Any of the '60s vintage Radio Amateur Handbooks, though, will have 'grid-dip
>meter' construction articles, and a grid dip meter is exactly a TRF receiver
>(not terribly sensitive, though, as they usually leave out the
>preamplification).  After mid-60's, the grid-dip meters used MOSFETs (what's
>a 'grid' in a MOSFET?).

Well, in fact the 1963 Radio Amateur's Handbook has schematics for
single-stage tube TRF receivers; you would just build a detector stage
(plate detector, infinite impedance detector, or grid-leak detector) and
wire the antenna to the RF input.  You could then add an RF amplifier,
if you wanted, remembering not to cheat and do any conversion stages ;-).

As for no one building a TRF receiver in most of a century, check out the
Ferranti ZN414 AM Receiver chip (available from Circuit Specialists and
a couple of other places).  It's a 10 transistor TRF receiver (4 amplifier
stages, detector, and AGC) built into a TO-92 transistor package; add
two resistors, two bypass capacitors, an LC tank, and an audio amp, and
you have a complete receiver.

(The 1963 Handbook also has a 110 page advertisement section that will make
you CRY -- MAYBE a quarter of the advertisers still exist)

whit@milton.u.washington.edu (John Whitmore) (04/12/91)

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