[Milsurplus] The TCS question

[WF2U]

-----Original Message-----
From: milsurplus-admin@mailman.qth.net
[mailto:milsurplus-admin@mailman.qth.net]On Behalf Of Ray Fantini
Sent: Thursday, November 20, 2003 9:08 AM
To: milsurplus@mailman.qth.net
Subject: [Milsurplus] The TCS question

>..........was wondering what would happen if I use a higher plate voltage,
maybe 450 or 500 volts with the idea of a couple watts more,
A couple of watts more will add maybe a tenth or a couple of tenths of a dB
to your signal. In order to get one S-unit increase in your signal, you need
to increase your power by 6 dB, which means that you have to QUADRUPLE the
output of the transmitter. In terms of the TCS power output, you have to
increase it to around 100W to be received 1 S-unit stronger (transmitting
with the same antenna). This is impossible without completely destroying the
transmitter, or you can just use it as a driver for a higher power stage.
The problem with the increased voltages is that the components may fail on
you.
         >.....or if I can make the second RF tube active in the voice mode?
>..with a little more plate voltage on the modulator for increased
modulation. the real fear is that too much voltage on the plates will blow
the modulation transformer, although >looking at > this transformer it looks
just about as heavy as one in a ART-13 and they run at 100 watts with no
issues. as a end result would like to get about twenty to twenty five >watts
of AM  phone on a stock TCS transmitter. Has anyone else in the group worked
with this? anyone have any ideas on what the modulation transformer is
capable of? always >remember, AME sucks, their is no substitute for plate
modulation.
Ray Fantini KA3EKH
You can modify the mode switch to leave the second PA tube on when on AM.
However, the modulation depth is going to be way down from the original (the
TCS as designed, has about 30% modulation). The modulation depth can be
increased by adding another microphone preamp stage externally. Doubling the
power output on AM to 20 - 25 W will buy you only  half an S-unit increase
in your received signal.
Is it worth hacking up a nice classic radio which is irreplaceable nowadays,
as the TCS radios are getting scarcer and scarcer? Modification of an
antique military (or any other) radio renders it worthless for any future
sale.
I'm enjoying my complete, original, as issued TCS on the air and it works
just fine. Worked lots of  DX with it too.
My 2 cents' worth, your mileage may vary....

73, Meir WF2U
Landrum, SC