Radar Receivers

Between 1935 and 1939, before the start of the Second World War, scientists and engineers at Bawdsey Manor, on the East Coast of England were working on various radio direction finding (Radar) equipment for future airborne and land-based operation.  For the radar receivers they needed a good quality (and stable) broadband, intermediate frequency (IF) amplifier assembly with a gain of about 80 to 100dB.  The scientists were led by Dr.' E.G. Taffy' Bowen, (who later became known as the "father of airborne radar").

At the suggestion of Professor Edward Appleton, in May 1939 Dr. Bowen visited the Pye works in Cambridge.  Edward Appleton (later Sir Edward Appleton), had previously been his Professor at King's College, London and by then was the Jacksonian Professor of Physics at Cambridge University.

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, band-pass 45 MHz amplifier based on the Mullard/Philips EF50 valve, and most suitable for use by the team at Bawdsey for processing radar returns. With help from B. J. Edwards, then the Technical Director of Pye Radio Limited, Bowen left Cambridge with several samples of the Pye TV chassis. The cathode ray tubes developed by Pye were also found to be suitable for radar display applications.

This meeting between Edwards and Bowen led to further co-operation between Pye and other Government telecommunications research establishments.  The final outcome of Bowen's visit was that the Pye design, using the Mullard/Philips EF50 valves was adopted as the standard  IF amplifier strip for most of the radar equipment designed in the UK during the War.  Pye Radio Limited, together with other radio manufacturing companies in the UK, produced many thousands of radar sets using the Pye design and the EF50 valve during World War II.  The early airborne interception radar (AI) and air-to-surface vessel radar (ASV) receivers were manufactured by Pye, E.K. Cole and EMI.  The Pye co-axial connector was developed at this time to allow convenient RF interconnections to be made between the modules of airborne radar systems.

First Pye Army Wireless Sets

In August 1939, Pye was asked to quote for the manufacture of an Army man-pack radio transmitter/receiver for the Infantry, which had been designed by the Government Signals Experimental Establishment Department (SEE).

After careful consideration, Pye declined to quote for the manufacture of the set as initially designed, because the Company considered it too costly to manufacture and too heavy for the application.  However within 6 weeks Pye offered the prototypes of two alternative configurations to the Ministry of Supply.  These were built in light-weight tin cases with heavy ribbing for strength.

Eventually, after successful field trials in France, orders were placed for one of these alternative designs and the equipment was designated Wireless Set No.18.  This set was developed by a small team, which included Donald Hughes and William Pannell.

A small quantity (about 500) of the original SEE designed sets were manufactured by Murphy Radio and called Wireless Set No.8, however Royal Signals figures show that by the end of hostilities, 76,000 of the improved Wireless Set No.18 design had been made by Pye and other manufacturers (Invicta Radio - another Stanley family company, Murphy Radio, Bush Radio and EKCO).

Donald Hughes was also the principal designer of the famous Pye Wireless Sets No.19, which soon became the standard UK radio set for armoured fighting vehicles (AFV) used by the British Army and also in many other vehicles and ground station applications.

For a time Pye was the only manufacturer of WS19, but eventually three other British and six other companies in the United States, Canada and Australia were also contracted to manufacture the MKII and MKIII Wireless Sets No.19. in order to increase production.  Some of these later sets produced under the Lend-Lease scheme had dual English/Russian front panel and dial markings. A total of about 115,000 WS19 sets were manufactured during the war by the various companies.

Wireless Sets No.19 contained three different communications systems in one case - two separate transmitter-receivers and an intercommunications amplifier.

The main 'A' set, which was used for medium and long range communications covered the frequency range 2.5 to 8.0MHz in two bands, and the 'B' set, which operated between 229 to 241MHz for short range communication between tank  commanders.

The 'B' set (which fulfilled part of the specification of Wireless Set No. 24) could be claimed as the first ever Very High Frequency (VHF) mobile radio that was built in quantity by Pye.

First VHF Hand-held Portable

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.  This was intended to fulfill part of the specification of Wireless Set No. 24, and was proposed to the Government in a secret report dated 9 November 1942. However, this revolutionary concept was turned down.

It is believed that samples of this hand-held radio were sent to the USA with the Tizard Mission, and shared with the Canadians.  Just after the war, in 1946, this Pye hand-held 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.

Other Military Wireless sets

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.  W.M. Pannell also led the design of this set, and Pye and the Mitcham Works factory of Philips Lamps Ltd manufactured a total of 55,000 of this equipment during the war.

An add-on linear amplifier called Amplifier RF No 2 was also designed by Pye to boost the transmit power output of the WS19 and WS22 equipments.

Another military wireless set funded, developed and manufactured (only) by Pye during World War II, was the Wireless Set No. 62, intended as a replacement for WS22.  This was a lightweight, low-power (0.5 to 1.5W), high frequency mobile transceiver covering the frequency range 1.6 to 10.0MHz in two bands. It was constructed mainly of aluminium and was designed to withstand immersion in water for up to 5 minutes. The British Army adopted this as a vehicle mounted station for un-armoured vehicles, as a man-pack station for use by airborne troops, and also as a portable animal-pack station.  W.M. Pannell was again the principal designer and started work on the design in early 1944.  First prototypes were demonstrated at RAF Leeming Bar in Yorkshire in June 1944, and shortly after this Pye was given the go-ahead for quantity manufacture.  In February 1945, about 200 equipments had been delivered, and at the end of the war Pye Ltd had manufactured 7,350 WS62 units.

After the war, Pye continued to supply the WS62 to various armed forces and later sold the WS62 commercially as a rugged HF transceiver.  This remarkable set was still in volume production in 1955 and was finally removed from the Company product catalogue only in 1965.

In early 1944 Pye finalised the drawings of a portable communications receiver type PCR which covered long, medium and short wave bands.  This equipment was based on the receiver section of the Wireless Set No.19 "A" set, together with an external PSU and internal loudspeaker.  This receiver is often mis-described as a forces entertainment receiver, which became its later post-war role.  However, according to wartime Pye employees, it was intended to be used for reception of Army information broadcasts by troops in Operation Overlord, the D-Day invasion, and was also dropped to Resistance Groups in Norway, Holland and France.  Pye was contracted to produce 17,000 of these receivers, and Philips Lamps also manufactured the design as did Invicta Radio, London, a company managed by C.O. Stanley's sister, Pearl.  Donald  H. Hughes has now been identified as the design authority for the PCR receiver family from original blueprints.

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 worlds first multi-channel Time Division Multiplex (TDM) microwave radio relay link, and operated in the 4GHz frequency band.   WS10 was used by the British Army following the D-Day invasion to maintain communications back across Europe and over the English Channel to Jersey and then by land-line to London.  Pye was initially contracted to produce 400 of these units, and the design was shared with USA companies who subsequently pioneered commercial microwave links after the war.

During the War, Pye Limited expressed great dissatisfaction with the Ministry of Supply procurement system, which led to other companies being given contracts to manufacture larger quantities of the Pye designs than Pye itself.  This led to an increasing reluctance by the Company to accept military design contracts (as opposed to military manufacturing contracts).  As a result, the design of Wireless Set No.62 was privately funded by Pye Ltd, and subsequently only manufactured by Pye Ltd over its 20 year production life.

Following the War, Pye Ltd largely (but not completely) withdrew from the military supply field to concentrate on commercial two-way radio, trading as Pye Telecom, and also industrial electronics and domestic radio and TV.