By Frank Barlow ZL2NB
In part two he covers 1941-45, the period of the Japanese War. The whole character of Awarua changed during this period to meet the demands of wartime communications.
1941 was not a good year with the war in Europe. Britain was still battling away on its own. Germany had invaded Greece and Yugoslavia, and its troops were deep into Russia on a seemingly irresistible onslaught. There were also ominous rumblings in the Pacific, and both Britain and the US were reinforcing their bases there.
Intelligence gathering by the interception of enemy, or potential enemy, signals was a priority and the British had established a section for this purpose at their base at Singapore. The Japanese had their own Morse alphabet known as “Katikana” and it was a prerequisite to learn this code before any copying of their signals could take place. It was decided that some operators at Awarua should do this and arrangements were made for them to go to the Navy Office in Wellington for this purpose; my turn came in March 1941.
There were four Naval Reserve telegraphists training there also and they were destined to go to Fiji to open an HF Direction Finding Station. After memorising the Katikana code (we were not allowed to keep a copy of it) I spent a week at Musick Point Radio ZLF at their High Frequency Direction Finding station. Here I was able to listen to a Catalina Flying Boat (PBY) on the way from the States to Australia. At this stage the US was ferrying these aircraft to form a reconnaissance squadron at Townsville on the Queensland Coast.
It should also be mentioned that before the attack on Pearl Harbor in December 1941, the US had scored a major triumph by cracking the Japanese secret codes and the information gained from these played a significant part in the war.
I returned to Awarua Radio from Musick Point in April and spent some time, along with others, copying Katikana messages from shipping operating on the 24 and 36-metre bands. Japanese shipping was very active; all sending to Tokyo Radio JJU. Later on I was shifted to the HF Direction Finding station to join other Katikana operators there. The HFDF kept a watch on the Trans-Tasman TEAL flying boats during the day and searched around during the night for any suspicious signals.
Things changed dramatically in December 1941 with the bombing of Pearl Harbor, and the entry of Japan into the war and for six months the Japanese moved steadily southwards. It was during this period that Awarua was organised into a Copying and Direction Finding Network. Japan had established a major base at Rabaul in New Britain and this station’s radio traffic to Tokyo was copied continuously by Awarua and then transmitted to the Navy Office Wellington by teleprinter.
The Direction Finding Network was set up by connecting the two DFs at Awarua ZLB and Auckland ZLF by landline and extending the line to Waipapakauri WPP where another HFDF was installed. The search for signals from enemy vessels was now coordinated by the US Naval Headquarters in Hawaii. A continuous watch was kept on Hawaii’s frequency of anything they wanted a bearing on. This information was passed immediately to ZLF and WPP landline. The actual bearings of these signals were then accepted from ZLF, WPP and, together with ZLB’s, were passed to the Receiving Station and then on to Wellington. Later this system was improved by the landline passing through the Navy Office and the bearings recorded there. They were passed back to Hawaii by the naval station Waiouru Radio ZLO, which handled the outgoing link.
The US Navy had a network of about 30 DF stations throughout the Pacific and they required their radio bearings back within 10 minutes. A weekly performance guide was circulated by them listing all their stations and their performances. Our group did reasonably well while the action was in the South Pacific. The Awarua group was at the bottom of the Pacific and there was another at the top in the Aleutian Islands; Dutch Harbour, Kodiak, and later Attu. ZLB DF could call in Suva DF if the bearing angles showed that the “fix” was getting close.
The frequency and callsign that was most regularly broadcast by Hawaii was 6710 kc/s, callsign RSN/. The last character of this callsign was the Katikana symbol known as “N Bar”, and was formulated as “dah, did, dah, dah, dah”. RSN/ appeared to be the universal callsign for Japanese submarines and the calling was unique in that the called station was preceded by an E (dit) and the calling station preceded by an I (dit, dit). Another unusual feature of these transmissions was the fact that the messages were always repeated, giving ample time to copy the message and take a bearing. The sending was always good and steady.
For a period the Japanese bases in the South Pacific kept changing their callsigns daily at midnight (3am our time) but this was no real hassle since all the stations were identified within 24 hours. Sometimes the Japanese operators forgot and used their previous callsign, but generally the station was identified by its note frequency and bearing.
There was heavy radio traffic preceding and following the Battle of the Coral Sea (May 1942) when a large Japanese Naval force heading for Port Moresby was met by a US Navy force. The battle lasted for four days and was fought mainly by aircraft, both carrier and land-based.
Four weeks later the Japanese thrust eastwards with a large force in an attempt to capture Midway Island but were met by the US Navy. This was the decisive battle of the Pacific, in which Japan lost four aircraft carriers and a major part of their air arm, effectively breaking their offensive power.
US Marines landed on Guadalcanal in the Solomon Island in August 1942 and were stalemated there for a long time. There was intense radio traffic in this area until the US Forces resumed the offensive in November 1943 by landing on Bougainville and Tarawa Islands.
Perhaps the nearest submarine that was detected was the large “I” class one that lay off Sydney Harbour and released three midget submarines which entered the port and caused considerable damage. This vessel had a very strong signal and gave a first-class bearing of 308°, which was the bearing of Sydney. The Japanese “Betty” reconnaissance aircraft could be heard sometimes when they were patrolling far south from their base. Sometimes we were directed to obtain bearings on FLPs (Friendly Lost Planes) which had been damaged and were seeking guidance as to their position.
A medium frequency Direction Finder working on the Bellini-Tosi system was installed at a later stage and was used to keep a watch on the Distress Frequency of 500 kc/s. It was used to work the National Airways planes flying from Dunedin to Invercargill, and also to keep a watch on Captain Mercer’s plane during his monthly surveillance flights around the Fiordland Coast.
Some time during 1942/43 a new HFDF was installed. It was a Marconi DGF 24/2 working on the Adcock system and was a more modern set than the original DFG 12. The receiver was a superheterodyne and the plug-in coils had been eliminated. The set was fitted with an oscilloscope, which was effective on strong signals without interference, but difficult to use on weak signals with interference.
As the US offensive got underway, aided by New Zealand troops in the Solomons, and Australian troops in New Guinea, the Japanese were gradually pushed back. From then on, and following the capture of Rabaul, radio activity in the area dropped as the centre of operations moved north. Signals became weaker, bearings not as good, and Awarua was not called in as much. With the capture of Guam in 1944, the US Navy moved their Headquarters there.
There was a DF examination introduced at some stage – I can’t remember when – but it must have been later in the war. A Radio Engineer conducted the test with equipment which produced a signal, interference and static, all of which was controllable, and could be fed into a Goniometer. When the examination was completed satisfactorily we were entitled to an allowance of £26 per annum if we were employed on DF duties.
The war with Japan ended with their surrender in August 1945 and this event signified the end of special services at Awarua.
I was transferred later to Milford Sound Radio ZMV, and this ended my connection with Awarua for a couple of years.
Of the many operators and technicians who passed through Awarua Radio during the war years, there must be a number in the Ham fraternity, and it would be interesting to hear of them or about them.
Finally the Jubilee Celebrations held in 1988 to commemorate the 75th Anniversary of the establishment of Awarua Radio in 1913 was a fitting and memorable event. If and when Awarua Radio closes as a staffed Coastal Radio Station, it is hoped that some similar suitable function would be arranged to commemorate its years of service.
[Originally published in Break-In, June 1992]