[Milsurplus] TCS Low-Power Operation

[Ray Fantini]

As low power as the TCS is in the AM mode to begin with don't see any reason why they would need an additional low power setting. Remember that the TCS transmitter removes one of the two PA tubes in AM mode and with their possibilities for poor tuning between the antenna and the general use of a short antenna in the first place the radio in a PT or any small craft would have limited range to begin with.
I have run TCS transmitters in the past and with a real antenna and eliminating the almost useless antenna loading box I think I was able to get a whopping four to six watts output. That was without adding additional capacitance or otherwise modifying the output tank but can only imagine that when in use with a short vertical antenna being too loud was not an issue. I always assumed that's why the TCS receiver was somewhat too sensitive being as broad as it was because the idea was it would be paired with a poor preforming antenna.
If you think of the original mission criteria for the TCS as a general use short range radio for use ship to ship or in the harbor it's a great radio but don't ever think it was intended for any long distance communications. What we do with the radio in Ham operations are far outside the original design intent.


Ray F/KA3EKH





From: Milsurplus [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of WA5CAB--- via Milsurplus
Sent: Thursday, January 26, 2017 1:33 AM
To: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] TCS Low-Power Operation

I think that it was a holdover from the Atlas 56Q, which was the transmitter only.  For it, Collins offered two power supplies.  The larger one supplied the (to most of us) normal 400 VDC.  The smaller one (and no doubt the cheaper one) supplied 230 VDC.  I would have to check the manual to confirm it but assume that both supplies furnished 12 VAC for the heaters and 12 VDC for the relays.

So I always assumed that it was a dollar thingy.

Robert D.


In a message dated 01/25/2017 18:18:31 PM Central Standard Time, ka1kaq at gmail.com<mailto:ka1kaq at gmail.com> writes:

PT boats on night patrol? No idea, actually. Would be different if it were switchable. Maybe it was just an option they made the procurers aware of as an extra selling point?


~ Todd/KAQ


On Wed, Jan 25, 2017 at 7:06 PM, Hubert Miller <Kargo_cult at msn.com<mailto:Kargo_cult at msn.com>> wrote:

Anyone know the "why" of TCS low-power operation?
I think this is only referred to on the transmitter schematic, where it, if i recall, shows screen resistors jumpered.
Why would they want to operate on the same B+ as the receiver?
My first thought was harbor use, but no other boat radios turned down their power for local use. You had
everything going from 10 watts to 150 watts.
What say?
-Hue



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