Radio Discovers Australian Scientist.
The Australasian Wireless Review, Vol. 1, No. 6, June 1923, Pages 8 & 9, published an article on valve manufacture by the G & R Electrical Company, Sydney, Australia.
The text is reproduced below:
Radio Discovers Australian Scientist
The Wonderful New Australian Radio Valve
As a general rule, scientists pursue the more or less even tenner, unsought and unheard of. Suddenly the world is startled by some wonderful discovery, the successful outcome of a long course of patient research, with its numerous initial failures. The discovery may be something which will materially aid the health or increase the wellbeing, convenience, and enjoyment of the human race, and the value of scientific research is tardily acknowledged by a more or less apathetic public.
During the war it was necessary that radio valves be manufactured in Britain, to keep pace the demands for “listening in” apparatus for both the army and navy.
Under Professor J.J.Thompson in charge of the Cavendish Laboratory at the Cambridge University, valves were produced for war purposes, mainly for the navy, both detector and amplifier types.
Mr. A. J. Garrod, of Sydney, NSW was a student at the Cambridge University at the time and for over two years he had the opportunity of studying valve construction is carried out at the Cavendish laboratory.
After the war, and shortly after his arrival in Sydney, Mr. Garrod met a kindred spirit in Mr. S. Radcliff, an industrial research chemist, who has specialised in high vacuum work, mainly up to that time, in connection with X- Ray Tubes, and its production of modern high energy pumps.
Here was just the right person to produce, what Mr. Garrod had in view, the ideal radio valve.
The construction of valves necessitates, first of all, perfectly balanced elements. The plate, the grid and the filament must be perfectly designed in relation to each other to produce a high standard of efficiency. The research work conducted at Cavendish Laboratory had conveyed to Mr, Garrod all the information necessary to achieve that end.
The next step in valve construction is to exhaust the glass bulb that the electron thrown of by the filament have a free and unfettered path to the positive potential on the plate, and the residual gasses in the elements have to be eliminated in order that the gas molecules shall not interfere with the free flow of filament electrons. This latter is a highly important matter, perhaps the most important matter pertaining to valve construction.
Mr. Radcliff’s knowledge of vacuum phenomenon enabled him to deal with this important problem very effectively, and special apparatus was derived for this purpose.
It was perceived that it was possible to produce a valve that would operate at the highest state of efficiency, both as a detector and amplifier, and with a minimum of difference of plate potential, when employed for either purpose.
For many months carful and painstaking research was pursued, during the course of which apparatus was devised, constructed, and perfected, and we have no hesitation in saying that the highly scientific apparatus now employed in constructing the G. and R. Valve is second to none in the world, not even, excepting that employed in the huge research laboratories of the great American valve manufacturing companies. As a matter of fact, the Garrod and Radcliff apparatus, for producing radio valves is the best yet known to the world of science.
By the courtesy of both gentlemen, the writer had the privilege recently of going through the G. and R. Companies laboratories, just outside Sydney, when the wonderfully complex apparatus was demonstrated. The finished product was tested; both as a detector and as an amplifier, in the writer’s presence and the results were almost perfection.
As a detector, the valve operates on a plate potential of 20 volts and an increase of 10 volts gives the peak of amplification efficiency, the main feature of the valve being that its characteristic curve is a “straight line” throughout the whole course of operation. As much as 200 volts may be impressed on the plate without any of the well-known “bluing” appearing, and which indicates impending ionisation. There is no advantage gained, however by increasing the plate voltage, as maximum amplification is attained with only 30 volts on the plate, and there need be no hesitation in stating that, at that potential, the valve functions as an amplifier, equal to any valve that has ever been manufactured, and that is saying a great deal, but it is said advisedly.
The diameter of the valve is about one inch, and it is about 3½ inches long overall. Four contact pins are secured in the base for connections, but as the valve is smaller than the standard American four pin valves a special socket is being manufactured by the company, which will act as either an adaptor, to plug the valve into standard four-pin valve holders, or it may be used as a valve holder proper, screws In the base being provided for mounting purposes.
Being an Australian production, there is no duty, exchange, and transportation charges to pay, and the Company has wisely decided to give Australians the benefit of this and has provided, that the G. and R. Valve may be retailed at 23/6.
Arrangements have already been made with a large British concern for the distribution of the valve in Great Britain, and the distribution in New Zealand has also been arranged for.
Extracted by Gary Cowans from a faded copy of the magazine.