Did 222 Group Catalinas operate on two WT nets?

[Rob Stuart]

In the files of the defence department’s Directorate of History and Heritage in Ottawa there is folder which includes a "Weekly Communications Equipment Return" for 413 Sqn dated 7.1.42. The unit had six Catalina I aircraft and the return says that each of them had one TR9 transceiver, two TA 2J transmitters and two RA 1B receivers. According to http://www.airbattle.co.uk/b_research_3.html, the TR9 was a somewhat old voice radio. Presumably they were meant to be used for comms between unit aircraft or with flying control. I’ve not been able to find much on the TA 2J and RA 1B but they must have been the WT sets. Presumably the reason why the Catalina I was equipped with two WT sets was to allow it to be on two nets at once. In the case of 413 Sqn, when it was based in Ceylon, and especially in April 1942, one of those two nets was apparently a 222 Group net for comms to and from aircraft patrolling out to sea. Can anyone say what the other net might have been? Or might the second transmitter and receiver have been on the alternate frequencies for the same 222 Group net?

Thanks,

Rob

[Resmoroh]

Rob, Hi,

Very difficult (but not impossible) for a singleton WOp to operate on 2 nets simultaneously! It is possible that there was, say, an Ops Net and an Admin Net. The Ops Net was worked all the time but the Admin Net was only worked, say, on the hour every hour. You could have one Tx/Rx tuned to one Net, and the other to the other. To work 2 Nets from the same set would require re-tuning to the frequencies of the ‘other’ Net every time you needed to change Nets! Re-tuning was not instantaneous. You needed to get the Tx/Rx up (and probably to change the length of the trailing aerial!). My guess (having only worked on the periphery of the Black Arts of the Wiggly Amps) is that the second set was simply a spare. After all, what use is a Catalina 3000 miles out over the ‘Oggin if it can’t report what it sees?
What we really need is an ex-Brass Pounder to give us “The Gen”!!
HTH
Peter Davies

[David Duxbury]

The TR9 was certainly an "elderly" type of British combined R/T set, but it was I believe kept in production and on operations until quite late in WW2 for taxiing and circuit work - its operating range was generally pitiful, but the later versions had crystal-controlled frequencies so were much easier to use and therefore more useful. Amazingly this short operating range was seen by some RAF Commands as an advantage which is why it remained in use on heavy aircraft (Bomber, Coastal) becasue it was believed that the Germans could not detect the weak transmissions, and it enabled all local control conversations between pilot and ground base to take place without worry of interception by the unfriendly types on the other side of the channel. After the war it was learned that in fact the Germans knew quite a lot about these transmissions and had consequently built special aerials to "pull in" them in, so were able to gain some advance detailed knowledge of the size and source of pending raids over the Continent by analyzing the R/T chatter at each airfield. Naturally this came as something of a shock to the RAF signals people.

"two TA 2J transmitters and two RA 1B receivers"
These were American-made sets, and it should not be too hard to find good technical specifications for them on Google. Many American-built aircraft in the RAF would have been equipped at the factory with these sets in WW2, such as Ventura, Mitchell, Liberator, etc - I think they may be US Navy type sets rather than USAAF, but I will not muddy the water further with pure speculation on this point - they may even be the manufacturer's designation! (specific USAAF sets usually had SCR prefixes, with various sub-items having BC prefixes, but from 1944 onwards most American sets had ben redesignated with Army/Navy, or AN prefixes, such as AN/ARC-5.)
David D

[David Duxbury]

Fuirther to my previous post, it was not unknown for certain aircraft to have multiples of various sets, although the only one I know for certain was the USAAF's SCR-274 Command set (or R/T to RAF). To give the required selection and range of frequencies, the SCR-274 HF set up (as fitted to A-20, P-38, P-40, P-51, B-17, B-24, B-25, B-26, C-46, C-54, etc) included no less than three receivers (BC-453A, -454A, 455A) and two transmitters (BC-457A, 458A). The later SCR-522 (VHF) had a single RX (BC-624A) and single RX (BC-625A), widely fitted in most USAAF types in place of SCR-274 equipment. However W/T sets (long range Morse, and othr functions, called Liaison sets by Americans) normally had only a single TX and RX.
David D

[Rob Stuart]

Peter and David, thanks for your responses.

One of 413 Sqn's Catalinas was shot down on 4 April 1942 by Zeros, after sighting the Japanese task force which was approaching Ceylon and while transmitting its sighting report. The WAG on watch at the time later commented that:

"I had been on radio watch doing my four hours when the action began. When the first cannon shells blasted in they knocked out my receivers but left the transmitters luckily. I'd got two transmitters but I had to use the generator of one to support the other. And I'd got a smashed Morse key so I had to bang the part together hopefully."

By "generator" I suppose he might mean "frequency generator", but I'm very hazy about such details. Can one also deduce that the two transmitters had been tuned to the same frequency?


Rob