History of NZ spark stations

Operating room at Awanui wireless station. The high-tension room is through the window at the right.

Operating room at Awanui wireless station. The high-tension room is through the window at the right. Photo: Awanui Scrapbook, Te Ahu Museum

By George Newlands ZL2THQ

The establishment of a wireless link between Australia and New Zealand was first proposed by the Marconi Company in 1902 but it was not until 15 December 1909 that an Imperial conference was convened in Melbourne to discuss the matter in detail. On behalf of New Zealand the conference was attended by JK Logan, the chief technical officer of the New Zealand Post and Telegraph Department.

One of the recommendations to come from this conference was for wireless communications to be established across the continent of Australia, between Australia and New Zealand, and between New Zealand and Fiji.

Australia undertook to build two stations, one at Applecross, near Freemantle, and another at Pennant Hills, near Sydney. New Zealand undertook to build two similar stations, one at Doubtless Bay near Kaitaia, to communicate with a Marconi station being built at Suva, Fiji and another near Bluff to communicate with Pennant Hills.

By 1909 the two principal systems, Marconi and Telefunken, had stabilised and tenders were called the following year for two New Zealand high-powered stations, with a reliable working range of 1250 miles, to be installed at Doubtless Bay and Bluff. The tenders also called for three low-powered stations, with a range of 500 miles to be located at Cape Farewell, Gisborne and Sumner.

Three companies — Lepel, Marconi (UK) and Telefunken — submitted tenders.

Surprisingly German

The successful tenderer was the Telefunken Company of Germany through their Australian agent, Australasian Wireless Ltd of Sydney, and it may seem surprising that they were able to sell their equipment to Australia and New Zealand, both British Dominions, ahead of the rival British Marconi Company.

Details of the Lepel tender are no longer available and the Marconi tender was considered prohibitive at £30,000 against £23,730 for the Telefunken system. System efficiency was considered also; the Marconi system required generator power of 200 hp against just 70 hp for the Telefunken system. Also, the British Government was at loggerheads with the Marconi Company at the time, over patents and royalties, and the Dominion Governments had been instructed not to deal with Marconi.

The acceptance of the German tender may seem all the more surprising, given the lamentable state of world affairs at the time and the powder keg that Europe was becoming. Any feelings concerning the Anglo-German naval armaments race and the growing hostility between the Kaiser and the so-called Triple Entente of France, Russia and Britain were over-ridden by practicalities. The German system was recognised as word class in all respects. The English speaking world held German science, technology and education in high regard and German expertise and education in the new technologies was unsurpassed, as were the construction techniques and reliability. Even at this early stage in wireless development, German electrical firms such as Siemens & Halske and Telefunken had ready markets well beyond Continental Europe.

The tender document, couched in the wordy legalese of the time and exquisitely detailed, makes interesting reading. The proposal, dated 30 November 1910, is addressed to the New Zealand High Commissioner in London (Mr Hall Jones) from the Telefunken company in Berlin. It comprehensively details major components, general conditions and a guarantee of service. It is interesting to note also that the company required the station sites to be selected by one of their own engineers. Only then would they give a guarantee of service.

The document was signed by his Excellency John Poynder Dixon-Poynder, Baron Islington, the Governor of the Dominion of New Zealand and by W McLeod and Walther Straeker, two of the directors of the Australian agents of the Telefunken Company. The tender was then concluded between Australasian Wireless of Sydney and the Minister of Telegraphs in Wellington on 9 December 1910 and a tender deposit of 300 pounds paid.

Marvel of technology

Some technical detail is in order here. The terms “High Power” and “Low Power” must be viewed in perspective. The high-powered stations worked with a 30kW input and were specified to provide an “oscillating energy of 15kW in the aerial”. The low-powered stations required 5kW input for an aerial energy of 2.5kW and were actually Telefunken type D shipboard stations adapted for land based installation.

The order for three low-powered stations was later increased to five and they were installed at Auckland, Wellington, Chatham Islands and on the Government steamship Tutanekai. As far as is known, nothing was ever installed at Cape Farewell, Gisborne or Sumner. The fifth set was a standby and spare parts source.

Paragraph 25 of the original tender document, referring to the high-power stations, is reproduced here verbatim and gives an idea of the detail and language used. It will be noted that it is one single, long sentence.

25: The said stations at Doubtless Bay and Bluff shall be capable of maintaining a minimum range of signalling seawards as aforesaid of One thousand two hundred and fifty (1250) nautical miles at a rate per day of seven thousand five hundred (7500) words each of five (5) letters during Ten (10) successive days of Twenty four (24) hours each and under all normal atmospheric conditions and shall be capable of sending during the day or night Twenty (20) words per minute each word consisting of five (5) letters and so that the signals sent from the said stations at the said speed may be read with accuracy and certainty at a distant station and so that signals sent from a distant station capable of transmitting signals for such distance as aforesaid at the said speed may be received and read with accuracy and certainty at the stations at Doubtless Bay and Bluff.

High-power sites

The sites chosen for the high-power stations were at Awanui in the north (Doubtless Bay) and Awarua in the south (Bluff) and thus the stations came to be named. The original callsigns for the stations were VLA for Awanui and VLB for Awarua. The sites, 100 acres each, were similar in aspect, being flat with good ground conductivity and no surrounding hills or forests. The construction of the stations was similar also. The dominant feature of the stations was the aerial mast. This was a massive triangular steel lattice structure, 9 feet across each side, 394 feet high and built to withstand a wind pressure of 25 lbs per square foot. It cost £1600 and the base weight, with the aerial rigged, was in the order of 120 tons.

Awanui Radio VLA, circa 1919

Awanui Radio VLA, circa 1919. All three guy anchor blocks can be seen. Photo: Northwood Brothers

The mast stood on a three-layer insulator consisting of iron plates interspersed with glass. It was supported by two sets of three guys, actually iron rods broken up with insulators, attached at the 150ft and 300 ft levels. The bottom ends of these terminated in three massive concrete anchor blocks, 42 tons each, with a tensioning shed at the rear. These anchor blocks are still in position today and are likely to remain so.

An interesting stipulation regarding the guy wires was that they had to leave the anchor blocks at a height in excess of that of a man standing in the stirrups of a horse, presumably to protect any horseman riding among the guy wires.

The construction of both masts was overseen by a Telefunken engineer by the name of Eugene Reinhardt. The company undertook to provide expert supervision during the construction of high-powered stations and Herr Reinhardt gained eminence in erecting stations throughout the world. He died in February 1959, aged 82.

Jas Twiss, Norm Furness, Eugene Reinhard at the base of the Awanui wireless station tower in 1913.

L-R: Jas Twiss, Norm Furness, Eugene Reinhard at the base of the Awanui wireless station tower in 1913. Three concrete plinths below the mast upright members allowed insertion of bottle jacks to raise the mast if the base insulator required replacement.

Aerials

The aerial was a high capacity umbrella type favoured by Telefunken. A large number of phosphor-bronze wires, (the spec. states “phosphorous bronze”), terminated in six groups at the top of the mast and spread out radially for about 1200 feet from the mast base to where they terminated on short wooden poles. The top 600 feet of these wires was the active part and the mast was part of the system.

Beneath this was a counterpoise, a radial earth mat of more phosphor-bronze wires ploughed into the ground, radiating out from the mast base to the limit of the aerial system. One can wonder at the necessity of this. The ground at both stations is swampy and conductivity good. Probably the installation of a counterpoise was a standard procedure with the Telefunken system.

The station buildings were the same at both stations and consisted of a power house, and a smaller building comprising a high tension room and an operating room. A superintendent’s house and staff quarters were also provided. Such was the similarity of the buildings at the two stations that photographs of the internal fittings and apparatus are often difficult to distinguish. (The operating buildings were indeed similar, but the accommodations were quite different, as can be seen in photos elsewhere on this website – Ed.)

Equipment

The powerhouse contained the main alternator and its driving engine. The specification called for a 70 hp “petrol-oil” engine and the machines were actually Gardner semi-diesels, started on petrol and switched to light oil or power kerosene when up to running temperature. They were started by compressed air.

The 75hp Gardner petrol-kerosene engine that drove the 30kW alternator

The 75hp Gardner petrol-kerosene engine that drove the 30kW alternator.
Courtesy: Te Ahu Museum. Click to enlarge.

The engine was belt coupled to a 30kW alternator which produced 220 volts at 500 Hz when running at 1000 rpm. This gave the transmitter a spark rate of 1000 per second and produced the high pitched “singing spark” note that was a characteristic of the Telefunken system. The use of a British engine is strange as Telefunken was part of AEG and would have had access to very good German engines. Probably a political decision.

30kW 500Hz alternator at Awanui Radio VLA

30kW 500Hz alternator at Awanui Radio VLA. Photo courtesy Te Ahu Museum

No attempt will be made here to describe the finer points of the technical apparatus. There is no reason to believe that the equipment was anything other than standard Telefunken and the system is well described in published literature. It is worth noting, however, that most of the equipment was made in Sydney and a brief description of the transmitter operation is in order.

High tension room at Awanui

High tension room at Awanui. At left are the keying relays and their blowers. In the centre is the step-up power transformer. The cylindrical objects to the left of the transformer are probably RF choke coils. At right is the bank of quenched spark gaps with their blowers. Behind them is a bank of Leyden jars. Tuning inductors are suspended from the ceiling.

The 220 volt 500 Hz power from the alternator was fed via massive keying relays to a step-up transformer producing 30,000 volts. These relays, equipped with air blast over their contacts, were an impressive and very noisy feature of the stations. The oscillatory circuit consisted of silver plated copper pancake inductors in series with a bank of Leyden jars and banks of quenched spark gaps. Like the keying relays, the spark gap banks were equipped with air blast. Coupling to the aerial was inductive with shortening condensers and inductors for tuning. The aerial was fed through an RF ammeter scaled for 250 amperes and generally reading about 50. All this produced the required 15kW of RF on wavelengths between 600 and 2000 metres.

Keying relays at Awanui

Keying relays at Awanui. These were controlled by the operator’s telegraph key and carried the whole 140 ampere primary current. Note the air blowers mounted below the relays. The switch at top centre is for earthing the aerial. (Relays of this type, probably from Awarua or Awanui, were seen to be stored at Ferrymeade Museum near Christchurch in 2016 – Ed.)

The receiving system was entirely conventional for the time and used the standard Telefunken “acoustic receiver” type GAH. These impressive machines are prominent in photographs of the operating positions, as are wavemeters of type EGW. The receiver is little more than an elaborate crystal set with provision for different detector types and tuning arrangements and the wave meter is a multiple indicator absorption type. Again, such equipment is well described in published literature. All instrumentation and equipment in the stations was of superlative quality and finish.

Services

Awanui and Awarua stations were opened for business on 18 December 1913. Information on exactly what services the stations eventually provided is now both sparse and scarce but it is obvious that Awanui was the busier of the two. The intended purpose of Awarua, a service in conjunction with Pennant Hills, obviously never eventuated although it can be assumed that tests would have been made. The station seems to have served chiefly as a marine communication and distress watch facility but restrictions imposed by wartime regulations, with ships required to keep radio silence, must have left the station with little to do.

The war with Germany started in 1914 and quite early a force was sent to Western Samoa to take over the German colony there. The operation was successful but the high-power Telefunken station at Apia was damaged by the German staff in an attempt to deny its use to the New Zealanders. Stories vary as to what actually happened but it seems that the engine governor was sabotaged and the flywheel disintegrated when it was started. A consignment of parts, including an engine flywheel, was sent from Awarua to get to Apia station operational.

On 8 March 1922 attendance at the Awarua station was curtailed to 6 am to 6 pm other than for a distress watch and the transmission of marine navigation messages but the station was handling commercial traffic again on 24 June 1925. A twice-daily service (9.15 am and 4.15 pm) to the lighthouse station at Puysegur Point was commenced on 1 August 1925.

A shortwave service, using thermionic valve transmitters was commenced from Awarua in 1924 and it can be assumed that the spark transmitter, or whatever remained of it, would have fallen into disuse at that time. (Valve receivers, De Forest 1Bs, had been introduced about 1916).

At this time radio broadcasting was becoming common and with domestic receivers of the day being designed for sensitivity rather than selectivity the powerful spark signals must have been less than popular with the general public. Shortwave services were taking over long distance communication and the longwave stations were having ever less to do.

By 1930 spark wireless had had its day and maintenance of the mast, always a substantial on-going expense, ceased. By 1938 it had deteriorated irreparably and it was felled on 24 March of that year.

Not much more is now known about the services operated by Awanui but it had a less passive role than Awarua. As with Awarua and Pennant Hills, there is no record of Awanui ever working a regular service to Suva, the service for which it had been built, although it did so for a short period in 1920 when the cable between Norfolk Island and Suva broke. Apart from assisting Auckland Radio with shipping traffic it operated a regular telegraph service with Apia between 1917 and 1927. On 12 January 1925 the station commenced broadcasting press messages on a wavelength of 2000 metres. These contained New Zealand news and were free to all ships and coast stations within range. This service ceased on 1 November 1927 (taken over by Auckland Radio) although a weather report was still provided at 10.10 pm daily on 600 metres.

From 1 February 1929 the listening service at Awanui was curtailed to 9 am to 1 pm and 2 pm to 5 pm. The station was closed Wednesdays at 1 pm and all day Sundays and statutory holidays. With ever less to do, closure was inevitable and this finally happened on 10 February 1930. The station was dismantled, the land sold off and Radio Awanui passed into history. In retrospect this was an error because at the outset of World War II a complete new station had to be established at Waipapakauri, not very far north of Awanui.

Radio Awarua became Awarua Radio and remained an active station for another 61 years, providing a particularly valuable monitoring service through World War II. Awarua is roughly the same distance from Rabaul (New Britain) as is Tokyo and radio traffic from the Japanese base at Rabaul was monitored constantly at Awarua. The station also provided an invaluable High Frequency Direction Finding service over this period. With the closure of Awarua Radio, on 30 August 1991, a significant period of radio communication in New Zealand came to an end.

The original 394 ft mast at Awarua Radio being felled on 24 March 1938

The original 394 ft mast at Awarua Radio being felled on 24 March 1938

Acknowledgements

The author acknowledges the assistance and information provided by the following organisations and individuals:

Telecom New Zealand Museum and Archives
Break-In Magazine
Southland Museum and Art Gallery
FE Barlow ZL2NB
TR Clarkson ZL2AZ
C MacKinnon VK2DYM
GA Weston ZL1BLX
AR Williams
Dr AC Wilson

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