Fred Hoyle An observer of the world and a ponderer on its problems ...

A Secret War

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London Bombed WWII - US Government

The Hoyles began their married life renting a small new house in De Freville Avenue, Cambridge. It was not until the autumn of 1940 that Hoyle was posted, as a civilian, probably on Maurice Pryce’s recommendation, to the Admiralty Signals School at Portsmouth. He was to work on naval radar, at a salary one third of his income and exhibition as a research fellow.

He was transferred to the outstation at Nutbourne, not much more than a field of sheep, huts and horse boxes where electrical engineers were developing antennae. Based in Hut 2 he set about reading available material and
reports on radar. The report on aerial design of Type 79 radar gave Hoyle an idea on how to include the altitude of an attacker. He devised a simple Type 79 calibration model, which was used till the end of the war to solve the altitude determination problem.

Herman Bondi recollected:

The most important person is Fred Hoyle, who through making simple graphs, very early on enabled radar operators on (aircraft) carriers to determine the height of a plane from its fading pattern. I understand this was operationally very significant but he has never received proper recognition because it was a software not a hardware problem.

In the summer of 1941 he was joined by
Cyril Domb and later in April 1942, after being released from internment, by Hermann Bondi. In Autumn 1942 the renamed Admiralty Signal Establishment (ASE) was moved out of Portsmouth to relative safety. Hoyle was appointed director of Section XRC8 at ASE Witley with Bondi as deputy director. The final core member of the team, also released from internment, Tommy Gold joined in November 1942.

Tommy Gold recollected:

I felt I could not possibly have done better for myself than join the group. The great enigma to start with was the director, Fred Hoyle. He seemed so strange: he appeared never to listen when people were talking to him, and his broad North Country accent seemed quite out of place….
(I)n fact he listened very carefully and had an extremely good memory.

Quoted in G. Burbidge 2003 p 218

A key aspect of the team’s work was ‘Anomalous Propagation’ – short wave effects of water vapour. Such was the importance of the subject that an inter service propagation panel was formed, with ASE being represented by Hoyle and Frank Westwater, a meteorologist and fellow maths student from Emmanuel College.

To obtain data Hoyle set up a field experiment siting a radar transmitter on the top of Mount Snowdon, North Wales and a receiver in Aberporth, South Wales, thus giving a path of propagation across Cardigan Bay. This experiment was extended to include ‘Sea-clutter’ - reflections of the sea waves giving rise to noise, which masked the desired signal.

A further key area of work related to ‘Window’ – where strips of aluminium foil are released from an aircraft to mask genuine signals and confuse enemy radar. Hoyle was asked if there was a way to discriminate between the echoes from an aircraft and ‘Window’. To have access to a continuous supply of flying aircraft, Hoyle conceived an experiment based on the north Cornish coast. The radar set was sited near Bedruthan Steps on the flight path from the Coastal Command Station at St. Eval. Tommy Gold’s ingenuity in converting electrical information into sound provided the solution. Although not ready for use in the war it was used for many years afterwards.

Hoyle’s research group was highly successful but because of the ‘
Most Secret’ classification of their work they never received due credit.

But what of family life? It had taken some time for Hoyle to find adequate accommodation for a married couple near Nutbourne - a cottage attached to a larger house in Lye Lane outside East Ashling. With insufficient coal to run the range Barbara cooked every meal for ten months on a small camping primus stove. About the time of the move to Witley the Hoyles had just found a more suitable house to rent in Funtingdon. They were unwilling to start house hunting again, particularly as they now had a baby son, Geoffrey.

In early 1943 Gold found a farmhouse with three bedrooms to rent in Dunsfold, empty as it lay on the flight path of a nearby bomber station. He was joined by Bondi and during the week Hoyle stayed over, sometimes accompanied by his family. Rigorous discussions took place on the evenings the three of them spent together. Hoyle's enthusiasm for astrophysics was infectious and with his wide knowledge, insight and ability to explain problems, Bondi was soon taking further the work Hoyle and Lyttleton had done on accretion.

In 1944 Hoyle and Westwater were deputed to attend a conference on ‘Anomalous Propagation’ at the Naval Research Laboratory in Washington DC. Invitations were received to visit the radio propagation teams at MIT and San Diego.

Arriving three days before the conference, Hoyle chose to visit Henry Norris Russell at Princeton University Observatory. From Russell he received a letter of introduction to Walter Adams at Mount Wilson Observatory. On his trip to the West Coast he stayed the weekend at the observatory, hosted by Walter Baade, who had discovered two distinct stellar populations and opened up the study of stellar and galactic evolution. Baade brought Hoyle up to date with three years of progress in American astronomy. They talked about the implosion of massive dying stars and the nuclear explosions triggered by stellar collapse.

Hoyle returned via Boston and a meeting with Harlow Shapley of Harvard College Observatory and then by train to Montreal, ostensibly to visit radar stations in Ottawa. There he ran into Maurice Pryce who had joined the atomic weapons research team in 1942.

While Hoyle believed the war years had robbed him of his best years of research, it had introduced him to a number of players who would be significant in the years ahead.

He returned to Cambridge in July 1945. His apparent affluence of the immediate pre war period had gone. The purchasing power of money had halved; only eighteen months of his St John’s junior research fellowship remained and he could obtain only a temporary junior appointment as a lecturer to the Faculty of Maths. The price of houses in Cambridge had doubled and the Hoyles now had a second child, Elizabeth.