[Milsurplus] TCS Low-Power Operation

[Ray Fantini]

Thought the majority of TCS installations were for short range communications with vertical whip antennas, see picture at:

http://www.virhistory.com/navy/ant/ant-dd793-01.jpg

66047, 66053 with a lot of the antenna installations used again for the next generation of SSB radios. Think the point I am trying to make is the TCS was only intended as a short range low power set to begin with and when you seeing them being replaced with things like the URC-35 or later Sunair transceivers they were all 100 watt to maybe make up for the low power aspects of the TCS, so why would anyone ever want to reduce its low power further?
Perhaps it’s just me because I remember running a TCS on 40 for some time and did not get many contacts running that low of a power level. I went to running a TBW at around 100 watts and then the contacts started coming back. I know there are a lot of QRP people out there but not me. I know if I can barely hear someone calling CQ I won’t respond and assume that a great deal of other Hams feel the same.

Ray F/KA3EKH


From: Milsurplus [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of WA5CAB--- via Milsurplus
Sent: Thursday, January 26, 2017 11:10 AM
To: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] TCS Low-Power Operation

I have never seen an Ex-USN TCS transmitter with the jumpers pulled.  I still think that it was a hold-over from the pre-war civilian market.  There would have been no reason for any USN installation to have run the thing in the low power/low voltage mode.

As far as the most common antenna used, PT boats, the relatively few landing craft that had a permanent radio installation and vehicular installations used a whip.  From what I've seen or read, the majority of combatants and auxiliaries used a typically 40' to 60' end fed wire.

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480

In a message dated 01/26/2017 08:48:49 AM Central Standard Time, RAFANTINI at salisbury.edu<mailto:RAFANTINI at salisbury.edu> writes:

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<mailto: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.

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