[ARC5] TBS Radios (VHF for PT Boats)

J. Forster jfor at quik.com
Fri Dec 10 17:59:37 EST 2010


I'm not do sure about TBS on PT boats. One reason is the Tx HV came from a
several hundred pound MG set that ran on 115 VDC. The receiver runs of 115
V 60 Hz.

FWIW,

-John

================



> Dennis wrote:
>
>>Hmmm...  The account relates "excited chatter of the Martinis (PT
>>boats) on the TBS tactical radio...."  PT boats carried TCS radios.
>>Were they equipped with the TBS also?
>
> The following is from a 1945 USN publication "Know Your PT Boat" found
> at http://www.hnsa.org/doc/pt/know/index.htm .
>
> ----------------START EXCERPT
> ----------------------------------------------
> Notes for Radiomen.
>
> 8. Your VHF is not as secure as you perhaps assume. Transmissions over VHF
> have
> gone 400 to 500 miles beyond the horizon. PTs operating reasonably close
> to enemy
> territory or units can give away their position and valuable information
> by useless
> chatter over a VHF circuit. And remember, you are not the only pebble on
> the beach.
> Our planes use it extensively.  Unnecessary PT transmissions must not
> clutter up
> communications of a vital operating aircraft squadron. You may think the
> air is
> clear because you do not hear any transmissions, but, remember, they may
> be
> receiving you several hundred miles away where they may be making a
> strike. So do
> not depend on the term "line-of-sight" transmissions. It is not reliable
> at all
> times, hence guard the use of your VHF set much as you do the TCS. Jam
> sessions,
> razzle-dazzle cowboy stuff, and hot-shot vocalizing are all very amusing
> to you
> if you are a lunk head. Just consider the harm you can do to yourself,
> your
> shipmates, and our aviators and you will be sure to knock off all
> unnecessary
> transmissions. Even when another boat in your section cannot hear you,
> your
> transmissions may carry to out-of-sight areas where the enemy may be
> listening.
> Transmission security for both radios is greatly enhanced by the use of
> follow-the leader tactics, basic formations, and courses established
> before
> leaving the base, and prearranged rendezvous points and times if the boats
> get separated. When PTs operate in sight of land, special care must be
> taken
> in VHF transmission. The Japs have many monitor stations on land and they
> have
> made many experiments with VHF type of equipment. It is to be expected
> that they
> are aware of our approximate frequencies. Give a Jap station enough
> transmissions
> and a shore battery will be laying a shell in your cockpit. For valuable
> aids in
> operation and on your equipment see MTB Communication Manual, 1944.
> ----------------END EXCERPT ----------------------------------------------
>
> The above discussion contains this caution about VHF usage:
>
> "And remember, you are not the only pebble on the beach.  Our planes use
> it
> extensively.  Unnecessary PT transmissions must not clutter up
> communications
> of a vital operating aircraft squadron. You may think the air is clear
> because
> you do not hear any transmissions, but, remember, they may be receiving
> you
> several hundred miles away where they may be making a strike."
>
> This seems to positively indicate that VHF on PT boats, at least by 1945,
> meant
> something like the AN/ARC-4 (or even a SCR-522/624 variant) in the 140 MHz
> range,
> just as these sets provided similar capability for US submarines.
>
> In any event, it appears the PT boats had some sort of VHF set in addition
> to the
> TCS.  Were the PTs at the Battle of Suriagao Strait in late October 1944
> equiped
> with the same VHF as PT boats in 1945?  I don't know.  Even if they used
> something
> on the old "talk-between-ships" band of 60 to 80 MHz, was it a a TBS?  I'd
> suspect
> that a MBF would be more likely.  The MBF and (IIRC) TBS needs 115 vac or
> 115 vdc.
> Did a PT boat even have 115 volt power?
>
> As far as this article written by Admiral Holloway goes, I would bet that
> the reported
> radio chatter actually took place on MF/HF, provided by the TCS.  I doubt
> that a PT
> had a TBS (or even MBF) as its VHF set.
>
> It's frustrating that the many sites dedicated to PT boats seem to
> consider details
> about the radio gear to be uninteresting technicalities.  In that respect
> they are
> just like so many WWII aircraft "restorers" and operators.
>
> Mike / KK5F
>
> BTW:  "Naval History" magazine, the source for the article that is being
> discussed, is
> a wonderful magazine.  It is published by the US Naval Institute (the
> professional
> society for US naval officers).
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