[ARC5] WWII Liaison Set Usage (long)

[David Stinson]

----- Original Message ----- 
From: "Al Klase" <ark at ar88.net>
Subject: [Boatanchors] WWII Liaison Set Usage


> Do we have any good information of the actual usage of the liaison sets 
> in WWII bombers?
> I assume virtually all traffic was in Morse.
> Was encryption utilized?  What system?
> What was the typical profile of the radio operator's activities during a 
> mission?
> What was he listening for?
> How often, if ever, did he transmit?

The question of usage is complex. There is "by the book,"
which says contradictory things depending on the 
who, what and when of the material you're reading,
and "what they really did," which is reflected in testimony
and in the logs. 

One of the best sources we have for this are original 
Radio Operator logs.  I have a collection of originals and
a stack of copies supplied by a friend.

One must be careful not to jump to conclusions when
reading this old material. Context is important.
For instance, one can read: "Aircraft were to maintain 
radio silence" in several places. But if you read more carefully,
you find this applies only to bomber formations forming-up
and on their way to a target. 
In some Radio Operator (R.O.) accounts, a person can read: 
"We never used the Command Set" and join the "so that's
why they junked all this stuff" crowd. But that person would
be wrong. The logs are crystal clear- the Command Sets were
used extensively. A Radio Operator 
that was doing his job was to log *all* transmissions 
coming from an aircraft, including those
by the pilots over the Command Set (one reason the Command
Sets often doubled as an intercom in USAAC ships).
The R.O.s aren't lying; *they* didn't use the Command Sets- 
the pilots did. The R.O.s used the Liasion set.
Even the logs must be read carefully.
I have a collection of logs from R.O. Staff Sgt.  Joseph Bryant
in which he dilligently documented everything he was
supposed to (except sometimes he skipped logging
the 500 KC "nothing heard" watches).
I have others where the R.O. logged only his traffic
on the Liasion Set, not even noting his mode
(though from the text it's obviously CW).

Concerning the radios on a bombing mission:
Pilots used the Command Sets for any take-off instructions.
Once airborne, all ships observed radio silence until the target
was hit, when the lead ship in each flight sent a strike report.
The Radio Operator listened for order changes, which were sent
encrypted using a daily code (can't find my docs on the
codes at the moment), copied weather, etc. Orders were to be
decrypted and a written copy on a message blank delivered 
to the aircraft commander.  "In the clear" weather went to 
the Nava-guesser.  If the flight took place over water, 
the R.O. maintained the 500 KC watch at :15 and :45
after each hour and was supposed to log anything heard
(though many logs don't show this,
 I assume because nothing was heard).
The only transmission the Radio Op on such a mission 
was supposed to make was for Distress.

There were dozens and dozens of other aircraft 
and other missions with no such restrictions.
On cargo flights, ferrying and etc., the R.O. used
 the Liasion Set on CW for all kinds of routine traffic 'in the clear."
The logs do not show encryption, but a vast, bewildering array 
of "Q" signals and abbreviations were used extensively.
The R.O. was supposed to carry the codes of the day
and it's safe to assume he could decrypt any encoded 
messages; his procedures call for him to do so and
deliver written copies to the aircraft commander.
Most of these logs show requests for bearings, signal reports,
weather report requests, logs of listening to weather broadcasts
from various stations etc., all on CW.
In no case have I seen a log of a Radio Operator making 
an AM transmission, nor have I seen a log of a Pilot 
making a CW transmission, but I'd bet coffee and donuts
it happened at some time or other.

The short answer to "how were the radios used 
other than in bombers?" is:
Anytime and anywhere an AM HF transmitter was
needed for any reason, and BC-191/BC-375 was
on hand, it got pressed into service one way or the other,
from installation on ocean vessels to 24/7 transmitting
as a navigational beacon and even more unlikely situations.
SCR-274N and "ARC-5" HF transmitters
did duty as Control Tower rigs and flight-line vehicle radios.
If they needed an AM transmitter and they had one, 
they hay-wired it up and used it.

I've scanned a complete radio log from November 7th, 1944,
of a flight of Army cargo aircraft "DogFourMike" from 
Hickam Field at Pearl Harbor Hamilton Field in San Francisco.
The Pilot transmits to Hickam Tower on 6500 KC 
and listens to the Tower on 236 KC.
The Radio Operator's Liasion rig is on 4570 KC CW,
shifting later to 5165 KC.  He also logs copying weather 
broadcasts "listening for the M.Os" (maritime ops) on 457 KC
An Air-to-Ground on-route order to the pilot for flight level 
is at 1748 hrs, sent in-the-clear.
On arrival at Hamilton Field, 
the pilot uses the lower Command Set channel of 4220 KC, 
the Tower using the same freq to reply.
The log sheets can be downloaded at:

http://home.netcom.com/~arc5/ROLogs/ROLogP1.jpg
http://home.netcom.com/~arc5/ROLogs/ROLogP2.jpg
http://home.netcom.com/~arc5/ROLogs/ROLogP3.jpg
http://home.netcom.com/~arc5/ROLogs/ROLogP4.jpg

73 DE Dave AB5S