[Milsurplus] TCS-9 Output matching?

[Roger Basford]

Hi Robert,

The note I have about the moving of the ammeter is attached to the 
TCS-13 manual and was from serial number 1387, again there's no clear 
reason for it. I've had good results loading up a short piece of 
Flexweave wire, about 1.5 amps into 20 ft of the stuff, hung vertically. 
I'm using the A-58/15 for testing, a French copy, I think.

The TCS station is coming on well. You supplied the connectors a couple 
of years ago and I've just got around to setting up a PSU, as genuine 
TCS PSUs are unobtainable over here, and I think we have discussed the 
cost of shipping before! I have used a Heathkit HP-13 DC:DC 12 volt 
inverter to run the TCS; it supplies ~400V HT if you remove the voltage 
doubler and fit a bridge instead. A lot quieter and lighter than a 
dual-dynamotor PSU too!

73

Roger/G3VKM




On 05/05/2011 20:38, WA5CAB at cs.com wrote:
> Roger,
>
> The modification you refer to (moving the RF Ammeter from the ground 
> side of the Variometer to between the antenna post and the T/R Relay) 
> occurred at S/N 9363 of TCS-12 production.  The final NAVSHIPS does 
> not say why it was done.  TCS-13, -14 and -15 also have it at the 
> antenna post.
>
> The only official Navy mod for coaxial cable I know of was to use it 
> with TN-233/SRC to feed RG-162/U hard line and apparently still 
> feeding a short antenna.  The phantom antenna included in the tuner is 
> 12.5 ohms in series with either 100 uuf or 300 uuf.  The only change 
> to the transmitter (and receiver) was installation of Type N chassis 
> connectors.  Coax used between the transmitter and tuner was RG-9/U.
>
> If the phantom antenna you have is the A-58, it has 10 and 5 ohm 
> positions.  The 10 ohm position works OK with the TCS and the 
> BC-1306.  And it was originally made for the BC-191 in SCR-193.
>
> In my experience, the basic TCS transmitter will load a 30-50 foot 
> end-fed wire satisfactorily.  That and a standard 35 foot whip are 
> what I've seen used aboard several vessels.  And a 40 foot wire is 
> what my TCS-14 is hooked to.  If I were to need to feed a coaxial 
> cable fed antenna like a doublet, I think I would opt for the 1:4 
> balun (technically I guess it would be an unun) at least in part 
> because it is smaller and would be one less control to fiddle with.
>
> In a message dated 5/5/2011 2:13:12 PM Central Daylight Time, 
> Roger at new-gate.co.uk writes:
>> I think the mod I heard about was a link winding over one of the coils
>> in the output circuit, so quite like the balun suggested by another
>> poster. Using a Windom is a possibility here too, so I may give that a
>> try. I'd be interested to know what the military did when they wanted to
>> use the TCS with a bigger antenna than the supposedly standard 20ft whip.
>>
>> The mod to move the RF ammeter to the antenna lead was apparently
>> because under certain (unspecified) circumstances the meter in the
>> ground lead could show a reading when the in fact little power was going
>> out to the antenna. I have a second, junker, TCS TX here and that has
>> either had the mod done or was built that way.
>
>
> Robert & Susan Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480