[TMC] Sideband Exciters

Fri Aug 27 16:49:41 EDT 2021

Chris,

Don't know if you've discovered this page on tmchistory.org, but it's a
reasonably comprehensive list of everything that TMC built over the years:

https://tmchistory.org/tmc_tables/tmc_comp_list_table.htm

As you've noticed, TMC built a bunch of electronic tinker-toys.  That may
seem strange, but, when a request for quote (RFQ) came down from the Navy
or other government agency for a particular piece of gear, TMC could often
put a proposal together very quickly using mostly already-existing
components, mixed/matched in a new way.  You can see how this worked for
some of the major systems that TMC supplied to the government, by having a
look at the military 'system' manuals:

https://tmchistory.org/tmc_manuals/tmc_military_manual_page.htm

You can also get an idea how these systems were composed by going to the
tmc_comp_list_table above, then scroll down to the "SBT-xx" entries, just
by way of example.  There are SBT-350's of many flavors (350-watt
transmitters configured in various ways). The chart lists the sub-units in
each of these transmitter config's.

To take just one example, the SBT-350R was an AM/CW/SSB transmitter with
350W (PEP) output power.  It consisted of 1 each:

SWR-1K,  TMC's handsome cross-needle SWR meter
PAL-350, a 350W RF linear amplifier with power supply
SBE-2, a many-featured SSB exciter that could also do double-sideband and
carrier insertion for "AM"
VOX-5, a multi-output variable frequency source
APP-5, a power patch panel

And then, of course, there are a BUNCH of SBT-1K's (1KW PEP transmitters)
in many dozens of configurations, and a zillion GPT-10K, -40K, and -200K
configs as well (10KW, 40KW, and 200KW PEP transmitters that were probably
TMC's most successful products).

TMC continued to offer separate frequency sources and exciters right up to
the end..  The VOX and PMO frequency sources were sold right into the 90's,
but in the 1970's the company introduced the MMX series of exciters, which
included frequency generation.  They were marvels of compactness and
extremely flexible, but they had a terrible reputation for reliability..
there's an amusing cartoon on the website somewhere.. :)  Anyhow, the basic
SBE- series of "analog" exciters was gradually replaced by synthesized
ones, the first of which was the SBG.  SBG's were among the very first
commercial synthesized SSB exciters, were insanely complex, and took up an
entire rack.  Nick K4NYW has one of them in regular operation.  Our friend
John Vendely K9WT has *many* ancient synthesizers operating at his QTH in
Florida.

If you REALLY want to geek out and get into the nitty-gritty of all this, I
have several of TMC's proposals in response to RFQ's from the government.
I could easily scan them and get them online.. :)

73, John K4OZY

On Fri, Aug 27, 2021 at 3:14 PM Chris Bolkan <bolkyboats at gmail.com> wrote:

> That is an awesome build Meir! Very clever and neat looking implementation!
>
> My goal is also to ultimately build a complete basic TMC station. To
> that end I have GPR and PAL but no SBE or Master oscillator which is
> why I am trying to figure this out. I have to know what I am looking
> for so if/when it becomes available I know what I need :-)  By the
> way, thanks for the tip on the SBE models.
>
> Now I understand that the SBE will run self contained on crystals, but
> to variable tune it will require a VOX of some kind. I have not looked
> at the PMO's so will do that to become a bit familiar with them too.
> For my use I cannot imagine requiring multiple outputs that you say
> the 0-330 does, but it is a Nice looking piece!.
>
> I wish there was more information and examples on how this TMC
> equipment was actually deployed and used. It would be a godsend to
> understanding all of the individual components they produced. One
> thing is certain. They were prolific designers and created some
> beautiful equipment!
>
> Chris
>
> On Fri, Aug 27, 2021 at 11:18 AM Meir Ben-Dror WF2U <wf2u at ws19ops.com>
> wrote:
> >
> > Chris,
> >
> > Nick is correct of course, but as TMC master oscillators are concerned,
> besides the VOX series, you can also use a PMO if you need only one output.
> Another advice: the older SBE-2 is a pain in the neck, but the SBE-3 (and
> up) is much better and if needs to be, easier to align.
> > Here is my multi-mode 350 W TMC system I put together; I had enough
> space in the rack to mount the GPR-90RXD receiver in it as well, and a
> homebrew dual speaker panel, for single rack integrated station. I have a
> PMO in there, because the VOX I have needs some work, but I'll keep the PMO
> in the system.
> >
> > 73, Meir WF2U
> > Landrum, SC
> >
> > Get BlueMail for Android
> > On Aug 27, 2021, at 1:59 PM, Nick England <navy.radio at gmail.com> wrote:
> >>
> >> Yes you also need a variable master oscillator like the TMC VOX (O-330).
> >> Otherwise the SBE can run crystal-controlled and has a switch for
> multiple
> >> crystals. For many government and commercial applications, crystal
> control
> >> was fine.
> >> Hey, it’s TMC.
> >>
> >>
> >> On Fri, Aug 27, 2021 at 1:31 PM Chris Bolkan <bolkyboats at gmail.com>
> wrote:
> >>
> >>>  Hi TMC lovers!
> >>>
> >>>  I have been looking at a few TMC transmitters on the history site and
> >>>  am confused about something. It seems that most of the systems have a
> >>>  master oscillator (0-330 or something like that) in addition to the
> >>>  SBE exciter (SBE-3 or 3 or whatever)
> >>>  I am hoping to assemble a complete working transmitter at some point
> >>>  if it ever becomes possible to obtain the components, but at this time
> >>>  I know precious little about what is actually required to assemble a
> >>>  working transmitter. I thought based on reading and images of the
> >>>  controls on the SBE's that they contain the required oscillators and
> >>>  are self contained. My question is do they? Or is the 0-330 master
> >>>  oscillator required in addition to the SBE to have a fully functioning
> >>>  exciter, or is the "master" oscillator an "extra" that allows
> >>>  synchronization of multiple transmitters and receivers and so forth? I
> >>>  apologise if this is an ignorant question. I suppose I could
> >>>  eventually figure it out if I read enough on the history site, but
> >>>  it's not always easy to figure everything out looking at just manuals
> >>>  without an understanding of the original deployment and (intended use)
> >>>  for these devices.
> >>>
> >>>  Thanks in advance!
> >>>
> >>>  Best regards,
> >>>  Chris
> >>>  KI7NXY
> >>> ________________________________
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