Frank Barlow remembers Awarua Radio 1939-1941

By Frank Barlow ZL2NB

Frank Barlow ZL2NB

Frank Barlow

With the recent announcement that Awarua Radio ZLB is to be closed as a manned station, it is timely that some record be made of its activities over the years. As an operator there over the War Years, I would like to offer my recollections and, due to the length of the article, it is appropriate to divide it into two parts as follows:

  • Part I: 1939-41 Early days; pre-Japanese War
  • Part II: 1941-45 Later days; Japanese War period

I was transferred from the Dunedin Telegraph Office to Awarua Radio in 1939 to train as a Radio Cadet, which was the usual way in those days of obtaining staff for Coastal Radio Stations. The Dunedin Telegraph, like the other major offices, had a large number of Morse circuits, which gave good grounding in Morse operating.

The transfer suited me since I was from Invercargill and it was good to get near “home”. Awarua Radio is situated on flat, near-swamp, land halfway between Invercargill and Bluff and was built by the German Telefunken Company in 1913 just before the start of World War I.

Similar stations were built at Awanui in the Far North, and in one of the Pacific Islands (Samoa, I think). The transmitter was of spark design, working on a low frequency with high power, but it and the generating equipment had long since been removed from the transmitting building. The tall 400 ft steel tower had been demolished in 1938, but the three huge concrete anchor blocks for the guy cables remained.

The hall where this spark transmitter had been located had been converted into a temporary dormitory and this was where new arrivals at the station slept. The old Receiving Building (later converted for use as Domestic Quarters) was where we worked until a new Receiving Station was built some distance away.

The old building was basically two rooms, with the 500 k/cs Distress Watch, the Morse table with circuits to Dunedin and Invercargill at each end, and the Superintendent’s table in one room. The other room, called the “Short Wave Room” had the 36m and 24m marine band watches in it. Also in this room were the point-to-point circuits to Milford Sound, Jacksons Bay and Musick Point Radio.

At the end of the room was the “GBR” receiver which was about 4ft high, with a multi-turn loop on top. The receiver was fixed on the frequency of 16 kc/s, and the only adjustments you could make were to the volume control, the pitch of the note and the alignment of the loop aerial.

The British Official Wireless was broadcast from Rugby on this frequency and several short wave frequencies. The original station at Rugby had an output power of 350 kW with an aerial efficiency of 11 per cent. The mind boggles at the size of the aerial array to propagate on this very low frequency. Later, when the new Receiving Station was built, the old GBR receiver was not moved and reception was confined to the high frequencies only.

In the old building all reception and transmission was manual; copying by pencil on to message pads and sending on straight hand keys. The 1000-word British Official Press messages were sent forward to Dunedin for retransmission to Wellington. An essential part of the operator’s equipment was a case of sharpened pencils and a one-edged razor blade. Headsets were always used – there were no loudspeakers. There were no typewriters, apart from the one used by the Superintendent and Supervisor.

Shortly after I arrived at ZLB, the coastal vessel Waikouaiti ran aground in fog on Dog Island (ZMG), a small lighthouse island just out of Bluff Harbour. The line-of-sight distance would be less than 10 miles to Awarua Radio, and I can recall the spark transmission from the vessel really blotting out everything on 500 kc/s. This must have been an embarrassing grounding for the skipper as lighthouses, by their nature, are not normally navigational hazards. Fortunately there was no loss of life.

Three 150-ft lattice steel towers were erected early in the War to carry transmitting aerials. These were assembled on the ground and winched upright onto a concrete base.

One of three new 150ft towers being erected at Awarua Radio in 1938

One of three new 150ft towers being erected at Awarua Radio in 1941

The 500 kc/s Distress Watch was fairly quiet during the day but, come nightfall, signals came in from everywhere and so did the atmospherics. Apart from the other New Zealand Coast Stations ZLW Wellington, ZLD Auckland and occasionally ZLC Chatham Islands, the chorus was confined to the Pacific area with CIS (Sydney Radio) and KFS (San Francisco Radio) being the dominant players.

Singapore and Hong Kong Radio could be heard hammering away with their TTT Navigation Warnings of minefields laid near their harbour entrances.

The Silent Periods of three minutes at quarter past the hour and quarter to the hour, were the critical listening times.

The 36-metre band was the main global traffic band, and it was busy with Coast Stations broadcasting their traffic lists (TRs) and working vessels. Due to the war, all British ships maintained strict radio silence, but there was a lot of neutral shipping moving around. The SS Mariposa and SS Monteray (WHEX and WGEN), running from San Francisco to Auckland were regulars on the air and were distinguished by their “bug” sending. Vessels stayed within range of the medium frequency stations on 500 kc/s while they were within two days of the ports and then switched over to the high frequency stations.

The 24-metre marine band was open for 12 hours daily, but it was far less active than 36 metres. I worked my first vessel on this frequency, the Swedish tanker Pan Gothia (SIWN) coming through Bass Strait to New Zealand. The vessel asked for QSJ? (charges, please), which at that time was 73 gold centimes per word for foreign vessels.

The receivers used were National HROs with plug-in coils and operating from a battery bank in a separate room. These sets were reliable, sensitive, selective and gave good service.

The auxiliary accommodation in the “Old Transmitting Hall”, the “Bunkhouse” and the “Stone Hut” was no longer required. Somewhere around this time a new Receiving Building was built further away from the main buildings. All services were shifted over to it and the old receiving building converted into quarters for the housekeeping staff with a good sized kitchen and dining room. The new receiving station provided greatly improved working conditions.

A Small Ships watch came into service on 2162/2182 kc/s and this provided, for the first time, communication and weather forecasts to shipping on radiotelephone. A loudspeaker watch was opened to Campbell and Auckland Islands on 5965 kc/s, which was also the emergency frequency for Milford Sound (ZMV) and Jacksons Bay (ZLQ).

The Dunedin Morse circuit was closed and a Creed teleprinter link to Wellington opened to handle the press and increasing flow of Admiralty messages to the Navy Office.

With the increased services and staff the number of Supervisors was increased to give a full coverage over the 24 hours.

Awarua Radio was under the control of the Post Office and performed the services of a Maritime Radio Station but, with the advent of the Second World War, it also performed services for the Navy Office. This consisted mainly of copying messages from the Admiralty (London) to all British Merchant Shipping (GBMS), and sending them on to Wellington. These were broadcast from the Portishead transmitters (GIH, GIM, GIJ, GID, etc) on a range of frequencies and were addressed to GBMS, followed by an area number.

Our area was Zone 11 which covered New Zealand waters and a good portion of the nearby Pacific. These messages were addressed to GBMS11 and were all in five figure cypher. A watch was kept on the German Maritime Radio at Kiel (DAN) which was operating on the 35-metre band. DAN kept regular “silent periods” for shipping reports, mainly from UBoats operating in the Atlantic and although DAN could be heard repeating the received signal the actual vessel could never be heard. The signals were always short, of two or four letter groups, followed by a two letter group. The short duration of the transmission and the low power used, meant that it was very difficult to obtain a radio bearing on them. There was always a chance that a German Raider, out this way, would come up on this frequency, but they never did.

About this time the Admiralty introduced special short prefixes to be used before distress messages with the object of determining what sort of attack was underway before the radio was put out of action. Even if the victim did not complete the distress message the indicator would advise what sort of enemy was in his area and this sort of information was vital.

To assist with Naval communications a receiving link was opened from the UK using a large receiver, reportedly the shore terminal for the radio-telephone service to the trans-Tasman ship Awatea. The receiver had several stages of RF and was connected to an Undulator which produced an inked tape in Morse symbol at about 50 wpm. This was later fed back through an attachment above the keys on a typewriter and transcribed at hand speed.

Anyway, enough of this “operating information”; let’s go back to the start of the war in 1939.

There were no technicians on the station at this stage and I can recall the Superintendent, “Hec” Head, puffing heavily on his pipe inside the 500 kc/s transmitter cage making some repairs. Later on, a technician was stationed at Awarua but there was little for him to do at that stage. The only transmitter that needed regular tuning was the Airways one, working to Musick Point Radio ZLF, and the operators did this themselves.

When the new receiving station was being built, new equipment was installed and the technical staff began to increase and eventually covered the full 24 hours. The days were divided into four watches of six hours over a seven-day week, but Sunday duty was at overtime rates.

The air service across the Tasman between Auckland and Sydney was established by TEAL (Tasman Empire Airlines Limited) in 1939 using Empire class flying boats.

Direction-finding hut at Awarua Radio

Direction-finding hut at Awarua Radio. Date unknown. Click to enlarge.

These flights were controlled by Musick Point Radio ZLF and by Sydney Radio VIS, the control changing at the halfway point. Radio DF bearings were taken by Auckland and Sydney as well as Lord Howe Island VZLH and Awarua Radio ZLB. The high frequency direction finder at ZLB was a Marconi DFG 12 of robust construction and screwed together like a Meccano set. The receiver was a Tuned Radio Frequency (TRF) with plug-in coils for the Goniometer unit and was housed in a small hut well away from any electrical interference, with four vertical masts and extensive earth net system in the swampy ground. This site would be a Ham’s “Dream Location”.

Communication to Musick Point was by point-to-point radio, with the receive signal from ZLF tuned in at the receiving station and relayed to the DF station which was about a mile away. Transmission was by keying the transmitter in the transmitting hall. Although the transmitter was of relatively low power, rhombic aerials were used at each end, giving a strong consistent signal on this fixed frequency in the 5-6 Mc/s band.

The aircraft provided a daily service across the Tasman, leaving at 8am, taking 7-8 hours to cross, depending on the wind. They called up every half hour giving their position report, followed by QTH? and a long dash for bearing. Messages were short and in code, which was cyphered on a SYKO board by moving the code letters to give a decoded version. On the rare occasions when they had engine trouble and had to return, it was distressing during a time of petrol rationing, to hear them signalling that they were dumping fuel (1000 gallons of petrol) before landing.

Weather reports are a regular part of radio life and Awarua took regular observations; these and others from Puysegur Point ZMU, Milford Sound ZMV and Jacksons Bay ZLQ were passed on to the Weather Office in Wellington. ZMU used to come up on 500 kc/s with a growly old spark transmitter.

When the Japanese entered the war, activities at Awarua became more urgent and intense and this is covered in Part II – from 1941 to 1945.

It certainly looks as though modern technology has overtaken the traditional roles of the coastal radio stations and that, regrettably, their keys could become silent in the near future.

[Originally published in Break-In, June 1992]

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