[TMC] TMC Digest, Vol 54, Issue 3

[John Poulton]

Mahlon, and the group:

I've actually seen four variations on the GPR-90RX.  I have a junker
that is pretty much nothing but an "improved" GPR-90.  Same front end
design as the '90, with the addition of the xtal panel and circuitry.

Another version has the 6AB4 1rst RF amp, but aside from the xtal
LO is much like the GPR-90.  Yet  another version is missing the BFO tube
and instead has an octal plug-in module (6BE6) that's a product detector.
And finally, the GPR-90RXDS, which has all of that, but is missing the 5U4
rectifier and has a pair of silicon rectifiers instead.  I believe these
latter designs have the 6DC6 RF amp as well.

There's also the question of the nomenclature.  R (Rack mount) and X
(xtal controlled LO) are common, but I'm assuming the D (Diveristy) only
applies to radios that were used in TMC diversity systems.  S is for
"Solid state" and describes the silicon-rectifier power supply mod, as
far as I can tell.  Are there any 90 RXS's, I wonder..?

There may be other versions, for all I know!  Be interesting to hear 
from others who have these radios..

At this point there are approximately a half-dozen of these radios
at my QTH...  Many are destined for other homes eventually, but before
they depart, I'll attempt to record all of their differences, and take
some pix.. :)

73, John K4OZY

On Sun, 30 Aug 2009, Mahlon Haunschild wrote:

> John,
>
> Note that there were/are two different GPR-90RXDs; one with a 6AB4 1st
> RF amp, the other with a 6DC6 1st RF amp.  There may (and most likely
> are) other differences.  The 6DC6 version appears to be the later of the
> two.
>
> regards,
>
> Mahlon - K4OQ
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Sat, 29 Aug 2009 14:56:05 -0400
>> From: John Poulton <jp at cs.unc.edu>
>> Subject: [TMC] TMC Price List posted
>> To: TMC at mailman.qth.net
>> Message-ID: <8FFD8162-0626-4A20-AAF0-557B800F6070 at cs.unc.edu>
>> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>>
>> Thanks to Hal, KK6HY, who sent me a good copy of the 1966 TMC price
>> list.  In all the years I've been
>> interested in, and collecting, TMC equipment, I've never seen one of
>> these, nor even talked to another
>> collector who had one!
>>
>> In any case, I just posted the list to:
>>
>> http://jptronics.org/radios/TMC/manuals/
>>
>> for your enjoyment.
>>
>> Just a reminder that I'm working through a mountain of TMC manuals,
>> which will eventually join the
>> stash already at my site.  There were 25 banker's boxes stuffed full,
>> and I'm nearly through Box #7.
>> There's nearly 2 GB of scans already done, with over 2/3 of the way
>> to go.
>>
>> If you haven't already done so, check out:
>>
>> http://jptronics.org/radios/TMC/manual_project/
>>
>> which contains some notes and initial scans from this stash.  Have a
>> look at the lists of equipment
>> and systems for which there are manuals.  I've shaded the ones
>> destined for scanning; if you see
>> something that you're interested in that's not marked, let me know,
>> and I'll add it to the list.
>>
>> Also, if you see something that you're really interested in getting
>> your hands on, I can easily move
>> it to the top of the queue!
>>
>> 73, John K4OZY
>>
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