Open Museum Archive

Challenger Transmitter
Object ID5229
Works NoN40-1100-01
Accession NoIF:2014:112
StatusBeing returned to service
Category Radio
Collection IDMarconi
Made ByMarconi International Marine Company
Made InChelmsford, Essex
Description1.5Kw HF transmitter
LocationPride of Calais Radio Bay, Radio Room

The following note from an ex R/O & Marconi employee:-

..... the equipment had only a short life; the initial, reduced, production run of 200 equipments was further reduced to 25 before any were finished (apart from 3 prototypes). How many of that 25 were delivered from the factory I can't recall.

I had some involvement with its Type Approval and pre-production testing and consider Challenger was the best marine transmitter ever to come out of the Marconi stable. We had long agitated for the use of forced-cooled, ceramic, output valves and wanted to have them in all transmitters after Crusader. However the then head of MCSL's Maritime Development Unit (to whom we had to contract all new developments) had a 'thing' about them and it was not until his retirement that we eventually got our way. Challenger was the first transmitter produced under his successor. It was outstandingly reliable from the outset, always stable, easy to install and to operate and had oodles of power to spare.

However it was a dinosaur - we in Marconi Marine's technical department had pressed for equipment that would be suitable for use by unskilled operators such as Mates on the bridge or Pursers. We were involved in the international group (IMCO) working on a project called the Future Maritime Distress and Safety System and could see that the era of Morse was coming to a close. The arrival of marine HF telex, closely followed by Comsat-General's Marisat maritime satellite service convinced us that the customer would prefer to have the same communications facilities aboard his ships as were present in his offices ashore - dial-up telex, telephone and facsimile. It made no sense for a major asset - a multi-million dollar facility manned by company employees - to be contactable only at limited times of the day and requiring the special skills of only one of those employees.

We wanted a 400-watt, solid-state, remote self-tuning transmitter/receiver coupled to a telex-terminal and automated selective call modem.

The Marine management were not prepared to make any radical steps and the new head of Marconi's Maritime Development Unit had limited solid state experience and was not convinced that such equipment could be built. The Marine Sales & Marketing manager stated that shipowners would not buy any transmitter with less than 1kW and that a traditional communications receiver was essential if we were ever to get any sales.

So the Challenger transmitter and Apollo 2 receiver were authorised and commenced development, the latter making much slower progress than the transmitter. Only 3 Apollo 2 prototypes were made and it never reached the pre-production stage.

Unfortunately the world had moved on whilst Marconi marked time and the auto-tuning transceiver and the magic words 'solid state' were now the must-have products. GMDSS was already being finalised and it was clear to us that the 1500W manually-tuned transmitter and separate receiver would not be required in future.

During the 12/15 months between approving the prototypes and the first Challenger coming off the production line, the Swedish PTT introduced their Maritex automatic telex service and it was announced that a marine international satellite service was to be introduced - it was to be called INMARSAT.

Then Skanti produced a 150W remote controlled solid state transceiver, followed soon after by a 400W version. With the Thrane & Thrane telex terminal they could offer a station that met all regulations but could be used by anyone capable of typing.

Just the thing that we had proposed but that Marconi said could not be done. That was the end of both Challenger and Apollo 2.