Sir Edward Fennessy, who has died aged 97, was a radar pioneer whose outstanding work during the Second World War was followed by a successful business career as managing director of Decca Radar, and later as deputy chairman of the Post Office.

Published: Daily Telegraph 6:25PM GMT 15 Dec 2009
http://www.telegraph.co.uk/news/obituaries/technology-obituaries/6819456/Sir-Edward-Fennessy.html

"Ned" Fennessy joined the Air Ministry research establishment at Bawdsey Manor in Suffolk in 1938. The work there was led by Robert (later Sir Robert) Watson-Watt, who had patented the first British "radio detection" technology three years earlier.

Fennessy played a part in the development of this system – later called radar as an acronym for "radio detection and ranging" – and the planning of a network of early-warning coastal "Chain Home" stations which were to play a crucial role in the Battle of Britain.

On September 29 1938, when war was thought to be imminent, Fennessy had driven through the night from Bawdsey to HQ Fighter Command at Bentley Priory to install the RAF's first radar operations room. But it was serviced by only five stations, and would have been, in his view, "quite inadequate" to its defensive purpose.

It was Chamberlain's negotiation of the Munich agreement that same day which bought sufficient time for the Chain Home network to be extended to 18 stations, giving Fighter Command a significant advantage in the air battle of 1940.
By the time war did break out, Fennessy was based at Harrogate, working on the Chain Home installation programme. At the time the only "office" available for him and a colleague was a bathroom; his desk was a door on top of the bath.
A bluff, tough and often outspoken Londoner of Irish parentage, he responded to an invitation to join the RAFVR by insisting that he would do so only in the rank of wing commander. After commissioning, he was shocked to find he was only a Pilot Officer (Probationary) – but he was soon in charge of offensive radio navigation aids in RAF No 60 Group.

Based at Oxendon, a Victorian pile near Leighton Buzzard, and staffed by former BBC technicians alongside regular officers, No 60 Group was known to Fighter Command airmen as "the Group that flaps but seldom flies", but it gave vital support to British and American pilots throughout the war. In January 1942 – by now a squadron leader – Fennessy took responsibility for the troubled project to establish "Gee" (G for Grid) ground stations to provide accurate offensive air navigation for Bomber Command and Coastal Command.

In late 1943, on his own initiative, he prepared a master plan for navigation and pathfinding systems to support a possible Normandy landing; but the Air Ministry reacted with horror when he presented his scheme, since he was not privy to the plans for the real landings.

He was briefly detained by provost marshals for breach of security, until he convinced them that his work was no more than a hypothetical concept. He was then "bigoted" – taken into the top-secret Overlord planning process – and so forbidden to tell even his immediate superiors at Oxenden what had transpired.
But he went on to oversee the radio navigation plan for the landings in June 1944, and the operations that followed, using Gee, Oboe, G-H and Loran "C" systems. On D-Day + 6 he landed in France himself, soon coming under fire from US troops unfamiliar with RAF uniforms. He was mentioned in despatches and appointed OBE in 1944.

Promoted to group captain the following year, Fennessy took charge of all RAF offensive terrestrial radio-navigation in Britain and Europe. At the end of the war Air Chief Marshal "Bomber" Harris declared that Bomber Command "could not have brought its work to a successful conclusion" without the contribution of No 60 Group.

Edward Fennessy was born in London on January 17 1912 and educated at St Bonaventure's grammar school in Forest Gate. After graduating from Queen Mary College, London, he worked first in telecommunications research, concerned with "sound location amplifiers" for Standard Telephones and Cables, before joining the Air Ministry. On demobilisation in 1946 he joined the Decca Navigator Co as a joint managing director. His first success was in selling navigation equipment to the Danish fishing industry, and he went on to launch the development of a simple but very effective marine radar system.

In 1950 he became the first managing director of Decca Radar, where he recruited a talented team of ex-RAF men to join him. He also found time to join the Royal Auxiliary Air Force, and for five years he commanded No 3700 (City of London) Radar Reporting Unit. Fennessy's entrepreneurial instinct as well as his formidable style of management – few dared to argue with him – drove Decca Radar to become a market leader in marine radar and to break new ground in aviation uses of the technology, including air traffic control equipment. The Decca 159 marine radar system, low-cost and simple to install and operate, was an early and enduring success. In 1952 he secured, and fulfilled, an MoD contract to supply Type 80 air defence radar systems, after competitors such as Marconi had declared that it would be impossible to meet the MoD's timescale. In 1962 he joined Decca's main board, but when its non-marine radar business was sold to the electronics group Plessey in 1965, Fennessy went with it, and in due course returned to his original specialism in telecommunications.

He was chairman of Plessey's telecoms research subsidiary, and of a joint venture with GEC and others which sought to secure for British manufacturers a slice of the growing world market for satellite ground stations. In 1969 he was recruited to join the Post Office, first as managing director in charge of telecommunications, and from 1975 to 1977 as deputy chairman. Among his many contributions on the technical side was a move to cut the 225,000-strong waiting list for new phones by the use of a fleet of mobile exchanges in areas lacking capacity for new lines. In 1975 Fennessy presented the 20 millionth telephone installed in Britain (it also happened to be the five millionth in London) to the Reverend Chad Varah of the Samaritans. But the Post Office was much criticised for slow progress, and in the same year Fennessy took exception to being described by the columnist Bernard Levin as "one of those clowns of such stupefying incapacity" who were responsible.

Fennessy was appointed CBE in 1957, and knighted in 1975. He was a founder member of the Royal Institute of Navigation, its president from 1975 to 1978 and a holder of its gold medal.

Ned Fennessy died on November 21. He married, in 1937, Marion Banks, with whom he had a son and a daughter. Marion died in 1983, and he married secondly, in 1984, Patricia Birkett, who survives him.