I have been seeking a transmitter to pair with my RAS reciever, and the TCS-12 looks very nice. I have access to a transmitter (just that, no other components).
I would be interested in hearing from TCS users about the ease of use of the transmitter, the vfo stability, the audio quality, and the use of non-oem power supplies (such as Heathkit, etc.).
Thanks
David Goncalves
W1EUJ
Hello Dave!
Been running a TCS outfit here for some time now, pretty much as Uncle Sam meant it
to be run, except for a homebrewed AC supply, and some selected (reversable) mods.
First off, a warning... RESPECT THE RECEIVER PLATE VOLTAGE SPECS! It calls for about
200 VDC, and the supply I built runs about 275 - 300. That caused a premature failure of
the RF gain control... and since the AGC switch is on it, in an unconventional setup, it
is a ROYAL pain in the butt to find a suitable replacement!
As has been already pointed out, in stock configuration only one of the PA tubes is used
on AM (they don't light the filament in the second tube). A couple of minor wiring changes
kept BOTH tubes lit in AM position, providing a good bit more output power and PA plate
dissapation capability... but that exacerbated a common TCS transmitter problem.
As you've no doubt already learned, the speech amp in the rig is minimalist, to the point
of the rig not HAVING a speech amp! With one PA lit, the modulation is poor, not even
able to hit 100%; with BOTH tubes hitting it, modulation percentages are a joke!
I do NOT want to hack up the rig too badly, and everything I do has to be reversable.
I haven't used the transmitter too much lately, but I think I've found a suitable answer
to the mod problem.
I came into a neat little plug in module made by Op Amp Labs; it's about a 2 watt audio
amplifier that will feed a low impedance (like the primary of the carbon mike to 1625 grid
transformer used in the TCS). It can be run off of the DC supply used to power the
relays in the TCS. A second Op Amp Labs module can be set up as a mike amplifier to
drive this stage; depending on the input it can use either the traditional T-17 carbon
mike (ugh!), or a dynamic mike. These modules are in octal cans, and can probably be
mounted inside of the rig without too much trouble.
On the transmitter I cheated on the plate supply; instead of 400 VDC my supply cranks
out 540 VDC under load. That extra PA and modulator plate voltage, along with both PA
tubes lit, makes for a VERY meaningful increase in transmitter power output, and the
transmitter doesn't seem to object any.
In CW operation... the note and keying are EXCELLENT on 160 and 80 meters. On 40,
things begin to get a bit chirpy, but still not too bad.
The first time I used the rig on 30 meters, my CQ was answered by a Cuban, and a lot of
those guys are notorious for BAD notes on CW.
When a Cuban complains about your clicks and chirp, it's DEFINITELY time to look into it!
<<grin>>
All in all, a TCS is a pretty good rig. Have fun with it.
73's,
Mr. T., W9LBB
