together with electrical and mechanical engineering. They were therefore able
to undertake a wide range of tasks in support of the war effort. Even so,
although deeply involved with issues of radar throughout the war, the GEC
were not initially involved with the terrestrial ‘Chain Home’ (Chap. 16) and
‘Chain Home Low’ systems.
4 These transmitters were manufactured by
Metropolitan-Vickers, the receivers by A. C. Cossor Ltd., and the ‘curtain’
antennae array by Marconi. The transmitter was designed by Dr. J. M.
Dodds
5 of ‘MetroVick’ using his ‘de-mountable’, water cooled tetrode valves
(Chap. 15). Whitehall had very little faith in the British radio community in
those days
6 and although GEC were one of the few they believed to be
capable of work of a fundamental nature, the contracts went to ‘MetroVick’
and Cossor simply because Watson Watt was familiar with their research staff,
and Dodds’ demountable valves were the only ones that could give the high
pulsed output power necessary (about 300 kW, later rising to 750 kW–
1 MW) at the wavelengths required for this form of radar. But for the
development of mobile radar in military applications, viz., artillery gun laying,
airborne and naval radars, the principles involved in ‘CH’ and ‘CHL’ had to
be drastically miniaturised and air-cooled anode valves naturally had to replace
their water-cooled cousins. It was here that GEC staff were far more intimately involved.
7
During the late 1930s, major developments in the Laboratories led to a
range of small ‘sealed-off’ oscillator valves which were immediately recognised
by those developing mobile radar systems as suitable for use as powerful
compact microwave transmitters. The first of these was made in 1939 and
became known as the E1046
8
‘micropup’, later as the ‘VT90’. Peak pulse
powers of as much as 200 kW were obtained from pairs of valves of this
kind.
9 The breakthrough in construction of these valves came when the
Laboratories realised that Houskeeper’s technique (Chap. 16) of connecting
two glass tubes together via a thin copper disc would make an ideal RF
connection to internal valve electrodes and this was adopted by GEC, firstly
in the ‘micropup’, and then in a series of increasingly more powerful ‘co-axial’
valves
8 such as the ‘milli-micropup’ (Plate 17.1).
The Laboratory also concerned itself with modulator valves for radar, and
small rugged valves for proximity fuses
10 in explosive shells, but developments
by other groups also attracted their attention—especially the ‘cavity’ magnetron—‘invented’ by John Randall and Henry Boot at Birmingham
University.
11 This became an essential concern for the Laboratories and a
‘game changer’ during the war. The Randall-Boot magnetron was a vacuum
tube with a solid cylindrical copper anode containing six ‘cavities’
406
D. Sheppard
to undertake a wide range of tasks in support of the war effort. Even so,
although deeply involved with issues of radar throughout the war, the GEC
were not initially involved with the terrestrial ‘Chain Home’ (Chap. 16) and
‘Chain Home Low’ systems.
4 These transmitters were manufactured by
Metropolitan-Vickers, the receivers by A. C. Cossor Ltd., and the ‘curtain’
antennae array by Marconi. The transmitter was designed by Dr. J. M.
Dodds
5 of ‘MetroVick’ using his ‘de-mountable’, water cooled tetrode valves
(Chap. 15). Whitehall had very little faith in the British radio community in
those days
6 and although GEC were one of the few they believed to be
capable of work of a fundamental nature, the contracts went to ‘MetroVick’
and Cossor simply because Watson Watt was familiar with their research staff,
and Dodds’ demountable valves were the only ones that could give the high
pulsed output power necessary (about 300 kW, later rising to 750 kW–
1 MW) at the wavelengths required for this form of radar. But for the
development of mobile radar in military applications, viz., artillery gun laying,
airborne and naval radars, the principles involved in ‘CH’ and ‘CHL’ had to
be drastically miniaturised and air-cooled anode valves naturally had to replace
their water-cooled cousins. It was here that GEC staff were far more intimately involved.
7
During the late 1930s, major developments in the Laboratories led to a
range of small ‘sealed-off’ oscillator valves which were immediately recognised
by those developing mobile radar systems as suitable for use as powerful
compact microwave transmitters. The first of these was made in 1939 and
became known as the E1046
8
‘micropup’, later as the ‘VT90’. Peak pulse
powers of as much as 200 kW were obtained from pairs of valves of this
kind.
9 The breakthrough in construction of these valves came when the
Laboratories realised that Houskeeper’s technique (Chap. 16) of connecting
two glass tubes together via a thin copper disc would make an ideal RF
connection to internal valve electrodes and this was adopted by GEC, firstly
in the ‘micropup’, and then in a series of increasingly more powerful ‘co-axial’
valves
8 such as the ‘milli-micropup’ (Plate 17.1).
The Laboratory also concerned itself with modulator valves for radar, and
small rugged valves for proximity fuses
10 in explosive shells, but developments
by other groups also attracted their attention—especially the ‘cavity’ magnetron—‘invented’ by John Randall and Henry Boot at Birmingham
University.
11 This became an essential concern for the Laboratories and a
‘game changer’ during the war. The Randall-Boot magnetron was a vacuum
tube with a solid cylindrical copper anode containing six ‘cavities’
406
D. Sheppard