Fwd: [Milsurplus] The TCS question

Fri, 21 Nov 2003 06:12:20 +0000

  Hi John,
            Yes the TCS discussion emails certainly do make interesting 
reading. Thanks for that.
Only one of the emails mentioned using a "carbon telephone insert" which is 
better than the original mic used (T17 derivative?).
A british No 8 carbon mic, similar to that used in older type telephones 
produces 90-100% modulatoion without the necessity to build a mic pre-amp, 
even when running both tubes on A.M. at this location.
Carbon mic quality though!
Running both tubes increases power output a little, but helps to share the 
loading between two tubes with a total of 110-130ma plate current when 
loaded into a resonant dipole.
The maximum power P.A. power should not exceed 60w on the plates if running 
two tubes.
The modulation transformer will not take any more without the possibility of 
causing damge to it.
My TCS12 transmitter & reciever recently restored, runs 425v & 225v. The 
reason why 225v was chosen was to cut down ambient noise in the reciever. 
These voltages are adequate enough to do the job!
I use 12v D.C. in the filaments. Useing A.C. causes hum when netting (i.e. 
the "M.O. Test" position.)
There is a good modification to avoid having to zero beat the B.F.O. onto 
the station, then net the transmitter to the B.F.O. a clumsy way to net, but 
has to be done due to high R.F. output from the V.F.O. & driver stages in 
it's normal configuration!
If interested, then drop me a line?
(I think the transmitter was never designed to be netted on to a station? I 
suspect either crystal control was used or split frequency operation in its' 
orignal U.S. Navy use?)
These sets are getting rare nowdays, so take care of them, you may not get 
another chance!

  73's George ZL2BGZ.

>From: John Nicholson <[email protected]>
>To: [email protected]
>Subject: Fwd: [Milsurplus] The TCS question
>Date: Fri, 21 Nov 2003 16:02:41 +1300
>
>Hi George,
>I am forwarding to you a series of emails from the milsurplus reflector on 
>the TCS, thought they might make interesting reading.
>73
>John
>
>
>>Delivered-To: [email protected]
>>Delivered-To: [email protected]
>>X-Mailer: Novell GroupWise Internet Agent 6.0.2 Beta
>>From: "Ray Fantini" <[email protected]>
>>To: <[email protected]>
>>Subject: [Milsurplus] The TCS question
>>Sender: [email protected]
>>X-BeenThere: [email protected]
>>X-Mailman-Version: 2.0.8
>>List-Id: Discussion of Military Surplus Electronics 
>><milsurplus.mailman.qth.net>
>>List-Archive: <http://mailman.qth.net/pipermail/milsurplus/>
>>Date: Thu, 20 Nov 2003 09:08:25 -0500
>>
>>I have been building up a new AC supply for my TCS transmitter, and  I 
>>know the B+ feed to the oscillator and doubler stages will be +250 like in 
>>the original installation but what I was thinking of playing around with 
>>the HV feed to the PA and modulator tubes. originally they were feed +400, 
>>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, 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
>>
>>_______________________________________________
>>Milsurplus mailing list
>>[email protected]
>>http://mailman.qth.net/mailman/listinfo/milsurplus
>

_________________________________________________________________
Download MSN Messenger @  http://messenger.xtramsn.co.nz   - add your 
friends!