After the Daventry Demonstration
The Tizard Committee was wholly convinced that Watson Watt's ideas
were worthy of support. & £10,000 (well over £ 1
M today) was quickly released for serious research work to begin.
Within 10 weeks (13th May 1935), four scientists including A.F.Wilkins
(who had set up the Daventry demonstration), E.G. (Taffy) Bowen
(later to be a key player in the development of airborne interception
[AI]), Bainbridge-Bell and Watson Watt (as Superintendent) were
transferred to Orford Ness, islet off the Suffolk coast. This is
a bleak and unforgiving spot but ideal for beaming out over the
North Sea with no physical hindrance whatsoever. It was from here
that Watson Watt's 'Chain Home' network was planned and it was here
that the first functional 'R.D.F' [Radio Direction Finding] system
was constructed.
By late June the team had constructed a transmitter and receiver
that could detect a flying boat at 17 miles. Within 2 months of
commencement, it was possible to achieve a detection range of 40
miles over the sea. The RAF were asking for a detection range of
100 miles. Already the early warning time had been extended from
2-4 minutes to nearly 11 minutes and the work had hardly begun!
Watson Watt was beginning to formulate a new idea that could give
defensive cover to the whole coast of Britain.
Note that the term 'RADAR'
had yet to be coined and was in fact an American term introduced
at the beginning of the war.
Some of the technical parameters of those preliminary
systems:
| Wavelengths employed |
50 Metres, 26 Metres and 13 Metres |
| Pulsed transmitter output: Power |
100kW |
| Pulsed transmitter output: Time interval |
20 microseconds |
| Detection range |
17 - 40 miles |
| Transmitter output |
water cooled silica envelope triode valves |
| Masts |
6 x 75ft wooden lattice, 2 for transmission, 4 for receiving |
| To determine the direction of aircraft (source) |
crossed dipoles in the horizontal plane |
| To determine the height of aircraft |
crossed dipoles in the vertical plane |
|
