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ZC1 Mk-1

ZC1 Mk-1
Circuit diagram
Internal views
Remote Control
Installation Type
Truck      Photo
Ground    Photo
Special committee
Collier and Beale
Radio Corporation
Radio Ltd

An example of the very early and rare Mk1 fitted with two Meters.



The ZC1 Mk1 is a 2 - 6 MHz, single band. CW, MCW and phone capable radio transceiver suitable for vehicle installation (jeep or radio truck) and/or field base operation. The receiver use's a 6U7G RF stage, 6K8G mixer, 6U7G IF, 6Q7G detector and 1st audio stage, 6U7G output and 6U7G BFO. The transmitter use's a 6U7G master oscillator, 6U7G buffer, 6V6GT PA, 6V6GT modulator and 6U7G modulation amplifier. The power supply use's a non-synchronous vibrator with two 6X5GT rectifiers in conjunction with a tapped transformer permitting switchable HT voltages to provide two different RF power outputs. Its power requirements are 12 volts at 4 to 6 amps depending on mode of operation. In transmit mode a maximum of 2.75 watts RF output is achievable in standard configuration.

Using the supplied 34 foot rod field base antenna and associated counterpoise earth, the transmission range is typically between 25 to 34 miles over rolling country. Use of more efficient aerials and sky-wave working permit much greater distances to be worked. The top sections of this antenna were suitable for mobile use over shorter ranges.


Design of the ZC1 Mk-1. is generally credited to Percy Collier and Bill Fever of Collier and Beale; a Wellington based radio design and manufacturing company. It was as far as possible designed around components readily available at the time, largely those used in the manufacture of domestic radios.  For the initial pre production trial assembly run many components were sourced from the large spare parts stock holdings of the New Zealand Post Office.

The special committee set up with representatives from the army, industry, Ministry of Supply and the Post Office to oversee the specification, design, procurement of components and the manufacture of the new radio was able to report in April 1942 that sufficient materials were now available for the manufacture of 750 sets of the 1000 Mk-1 sets approved.  Considerable difficulty was being experienced in obtaining certain components, especially meters.  The lack of meters forced a minor redesign so that only one meter was required in production sets.  The hole left in stocks of already manufactured front panels was covered with a metal plate fitted with a watch holder.  In later production the watch holder was fitted directly to the front panel.

The extreme difficulty in obtaining key components such as meters, tuning capacitors and radio valves had caused lengthy delays in accumulating sufficient sets of components to enable production to commence.  The ongoing delays in commencing manufacture was causing problems in retaining skilled production staff as the Draft Board struggled to find experienced qualified personnel to draft overseas to meet the growing demand for skilled service personnel.


At least three versions of the Mk I are known.

  • The first version, produced in small numbers, was fitted with an aerial current meter. IF transformers with fixed cores and variable capacitors were used.
  • The second version, also produced in small numbers, used the same IF transformers but had a plate with a watch holder fitted in place of the aerial current meter.
  • The third and most numerous version used different IF transformers with fixed capacitance and variable cores. The watch holder is fitted directly to the front panel without the need for a plate.


Key components such as meters, valves and the main tuning capacitors were all of Australian, American or English manufacture. Shortage of these components was to plague production until the later part of the war when American "Lend Lease" components became available. Official NZ war records show considerable frustration over shipping problems with large quantities of urgently needed, and already paid for, components being held up for many months on the wharves in the USA while officials argued over their shipping priority.

In all, it is now believed that approximately 5,000 ZC1 Mk I sets were made. However manufacture of the Mk I was barely commenced before design and production of the Mk II was already being planned.

Wellington based Radio Corporation was given contracts for the production of the ZC1 Mk I as was Radio Ltd of Auckland.

War Service

The first issue of the ZC1 Mk I was in the Pacific at Guadacanal and it saw active service for the first time when NZ troops landed at Vella Lavella at 8am on the 18th of September 1943. Official records indicate that it performed well in the dense and wet jungle out performing many other types in use at the time. The Mk I also saw service on Stirling Island where once again good results were achieved. The NZ 3rd Division 2nd NZEF records show that they used the ZC1 in conjunction with the American 48 set with good results. However given the relatively small overlap of the frequency ranges of the two sets, the choice of working frequencies must have been limited.     Photo ZC1 Mk-1 in operation Nissan Island 1944.  Photo 1    Photo 2

Use was also made of the ZC1 for general communications between the various support bases in New Caledonia.  Photo Radio Mechanician servicing radio equipment in Noumea.

This is the only recorded active service seen by the ZC1 in WW2.


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