The ZC1 Mk2 is a 2 - 8 MHz, dual band radio transceiver with a 2 - 4 MHz LF band and a 4 - 8 MHz HF band. The set offers CW, MCW and AM working and is 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 synchronous vibrator.
Its power requirements are 12 volts at 4 to 6 amps dependent on mode of operation. In transmit mode up to 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.
Initial experience with the Mk I in the Pacific proved the basic soundness of the design but also highlighted the need for improved tropicalisation and frequency range. Improvements made included the tropicalisation of components and improved sealing and weatherproofing of the case, repositioning of the antenna matching controls and meter, replacement of battery terminals with plug and socket, relocating the lamp socket to a more central position and other minor changes often dictated by the availability of specific parts at a given time.
The ZC1 Mk-2 is a development of the Mk-1 and it's design changes are generally attributed to J Orbell of Radio Ltd
Official records show that the Mk-II was originally planned to have a UHF transceiver included in the design matching the No. 19 set. The UHF section was to be an associated stand alone unit with it's own power supply. This idea was not followed up, although prototype UHF modules for this project were designed and constructed as a joint effort between Collier and Beale and the NZ Post Office Radio Section.
Key components such as meters, valves and the main tuning capacitors were all of Australian, American or English manufacture.
Wellington based Radio Corporation was given contracts for the production of the ZC1 Mk II as was Radio Ltd of Auckland.
In all, it is now believed that a little over 9,500 ZC1 Mk II sets were made.
A number of ZC1 Mk-2 sets were issued for use on the "Home Front" inside New Zealand in the last months of the War. This is the only recorded service seen by the ZC1 Mk-2 in WW2.