Between 1938 and 1939, before the start of the Second World War, a number of teams of scientists and engineers at Bawdsey Manor, on the East Coast of England were working on various radio direction finding systems (soon to be called radar) for future airborne and land-based operation. They had already designed a ground-based low-frequency radar system, called Chain Home, which was being installed around the coast to give early warning of high flying intruder aircraft. They were joined by scientists recruited from Cambridge, Birmingham and other universities.
For airborne radar receivers they needed a compact, good quality, broadband intermediate frequency (IF) amplifier with a gain of about 80 to 100dB. At the suggestion of Professor Edward Appleton, who was Professor of Natural Philosophy at the University of Cambridge and ex-Cavendish Laboratory, in May 1939 Dr. Taffy Bowen visited Pye Ltd in Cambridge. At Pye, Bowen saw the Model 915 television receiver chassis, which, as a Tuned Radio Frequency (TRF) type of receiver, was essentially a high gain, broadband 45 MHz amplifier based on the Mullard/Philips EF50 valve, and most suitable for use by the team at Bawdsey. The TV cathode ray tubes developed by Pye Cathodeon Ltd were also found to be suitable for radar display applications.
The eventual outcome of Bowen’s visit was that the core Pye TV receiver design, using the Mullard/Philips EF50 valves, was adopted as the standard IF amplifier circuit for much of the VHF airborne interception radar (AI), air-to-surface vessel radar (ASV) equipment and VHF ground radar designed in the UK during the War.
Due to the Pye relationship with Professor Cockroft of the Cavendish Laboratory, in October 1939, following the sinking of the Royal Oak Battleship in Scapa Flow by a German submarine, Pye (by then called Pye Ltd) was contracted to urgently manufacture three (later four) 150 MHz radar stations currently being developed for coastal defence (CD) to detect shipping. These were for use in the Orkney and Shetland Isles to watch for German submarines. This led to a further order to produce 24 additional stations (later a total of 52) of the VHF radar stations to be pressed into use with the Chain Home air defence network to detect low-flying aircraft, and designated Air Ministry Experimental Station Type 2 (AMES 2), otherwise known as Chain Home Low (CHL). See .
This led the Pye TV group into further co-operation with other Government radar and telecommunications research groups which resulted in war-time design and manufacturing work on a number of airborne and ground-based radar systems including: -
- Airborne Interception radar (Type AI)
- Air-to-Surface Vessel Radar (Type ASV)
- Coastal Defense radar (Types CD & CDU)
- Chain Home Low radar (Type CHL)
- Light Warning Set (Type AMES 2)
- Searchlight Radar (Type SLC or ‘Elsie’)
- Ground Movement radar (Type FA or ‘Watchdog’)
- Beam Approach Beacon system (Type BABS)
The Pye co-axial connector was developed at this time by Donald Jackson and George Baguley to allow removable interconnections using RF co-axial cables to be made between the modules of airborne radar systems.
During the late 1930s, the Army Council had taken the view that any future war would be a static conflict, very similar to World War 1 and that line communications using field telephones plus the Despatch Rider Letter Service (DRLS) would serve adequately well. As a result very slow progress was made in re-equiping the British Army with more up-to-date wireless communications.
It was not until August 1939 that Pye Ltd and Murphy Radio were asked to quote for the manufacture of Wireless Set No. 8, an Army man-pack radio transmitter/receiver for the Infantry, which had been designed by the Government Signals Experimental Establishment Department (SEE). Pye declined to quote for the manufacture of the set because the Company considered it too costly to manufacture and too heavy for the man-carried application. Within six weeks Pye offered the prototypes of two alternative configurations made in a case of thin tin-plate and featuring heavy ribbing for strength and after successful field trials in France, orders were placed for one of these designs, designated Wireless Set No.18. Royal Signals figures show that by the end of hostilities 76,000 of the Pye Wireless Set No.18 design had been made by Pye and other manufacturers.
Requests for Pye to design other urgently needed Army wireless equipment rapidly followed. Next came the famous Pye Wireless Sets No.19, which soon became the standard UK radio set for armoured fighting vehicles (AFV) and also many other vehicles and ground station applications. A total of 115,000 WS19 sets were manufactured during the war by the various companies involved. Wireless Sets No.19 contained three different communications systems in one case - two separate transmitter-receivers and an intercommunications amplifier.
It is not generally known that early in the war, Pye also designed a VHF hand-held radiotelephone for Infantry Soldiers to use for communication with the WS19 ‘B’ set in tanks. Just after the war, in 1946, this Pye hand-held VHF two-way radio was featured in a cinema newsreel film to demonstrate how such advanced communications concepts could be utilised in the future by the general public for personal radio communications.
Between 1941 and 1942 Pye designed the Wireless Set No. 22, primarily intended as a general purpose, low-powered radio for non-armoured vehicles and which could also be used as a man-pack or as an animal-pack set. Another military wireless set developed and manufactured by Pye (only) during World War II, was the lightweight and waterproof Wireless Set No. 62, intended as a replacement for WS22. Another Pye design for the Army was Radio Link Sound Ranging MK II, part of a system to detect the location of enemy artillery.
Pye also designed and produced the receiver section of the transportable microwave link, Wireless Set No. 10. GEC and TMC were responsible for the transmitters and the multiplex filtering respectively. This advanced equipment was the world’s first multi-channel Time Division Multiplex (TDM) microwave radio relay link, and operated in the 4GHz frequency band. WS10 was used extensively across Europe by the British Army following the D-Day invasion.
Pye Ltd was involved in other military wireless sets and more details can be found in the section on Pye Telecommunications Ltd.
Towards the end of the war, in February 1944, Pye Ltd registered a new company called Pye Telecommunications Ltd, in readiness for the anticipated post-war civil demand for radio communications equipment. Following the war, due to dissatisfaction with the Ministry of Supply system for allocating manufacturing contracts, Pye Ltd gradually (but not completely) withdrew from the main military supply contract business to concentrate on the markets for civil, industrial and professional radio communications equipment, together with industrial electronics, broadcasting and domestic radio and television.
Sources: 1. Mr. D. B. Delanoy 2003, 2. British Army Signals in the Second World War, Major-General R. F. H. Nalder, 1953, 3. The Radio Man, Mark Frankland, 2002, 4. Wireless for the Warrior, Volumes 1, 2, 3, Louis Meulstee, 1995, 1998, 2001, 5. Pye Telecom Historic Collection, 6. Bowen E.G., Radar Days, 1987, Adam Hilger, Bristol, 7. Memories of Radar Research, Cockroft J. D., IEE Proceedings-A Vol. 132, Part A, Number 6, October 1985 (original paper Royal Signals and Radar Establishment 4136A (S7, E15))