Wartime Radar Applications
World War II Klystron
This example, a CV35, didn't help to win as it's still in
its original box!
The klystron and magnetron were developed in great secrecy
during the early years of the war and enabled Britain to produce
static, shipbourne and airborne radar equipments to defeat the
Luftwaffe and the U-Boat menace.
Does anyone know in which set this valve was used?
And here's a couple undressed:
On the left a CV35 like that above but
without its waveguide attachment
And on the right another marked "CV67"
Another World War II Radar Valve
As you can see it's a "CFT-15-E" and it's a triode
with a directly heated filament. From the short leads it must
have been designed for VHF operation.
According to www.electricstuff.co.uk it's a 5Kw 600MHz triode
pulsed radar valve used in WWII bombers.
What was the radar and was it used exclusively in U.S. aircraft?
Does anyone know?
The box is dated August 14 1943 and measures about 3.5"
cube
RF Power Oscillator
This VTR135, having an International Octal base,
was originally supplied to the RAF and I believe is equivalent
to the DET20 and is classed as a small transmitting valve. Output
power is over 4 watts at 50 MHz although it can be used at lesser
powers up to its maximum rating of 300 MHz. It has a big brother
of similar appearance, the DET19, which is a twin triode used
as a push-pull output valve for higher powers. Below is a similar
valve carrying the code CV6 which is a "joint service number"
for the DET20.
Several methods were adopted to minimise the grid-anode capacity
coupled with reduced in-built inductance. This example uses the
simple expedient of two top caps. The valve was designed specifically
for use with a tuned circuit connecting its anode and grid. By
using silver plated wire a decent efficiency could be obtained
at VHF.
Having recently purchased a WS No19, that's the wartime
tank transceiver, I recalled where I'd seen this valve before.
In the 19 set is a simple super-regenerative receiver which doubles
as a transmitter. Output is around 230 to 240 Mc/s. It was used
for local tank to tank communications and officially had a range
of about 1000 yards.
On the left is a bird's eye view of the compartment containing
the valve.
It may also have been used in other equipment. Anyone any
ideas?
Other valves used in early VHF communications equipment, albeit
having a lower power rating were the acorn valves, the 955, 956,
957 and 958 which I used to buy in the 1950's for a few shillings
to build small super-regenerative VHF receivers for listening
to transmissions from the local airport. These valves, of which
all my examples unfortunately bit the dust years ago were tiny
things no more than an inch or so in height.
The smallest valves were made near the end of the valve era.
These were the "nuvistor"
types which were much the same physical size as some transistors
around at the time they were in use. The nuvistor had a good spec
at UHF and was often used as a front end in sensitive receivers.
In fact their performance was far superior to that of transistors
until the advent of semiconductor devices with gain bandwidth
products measured in GHz.
The 832 is another type of "twin-horned" wartime
VHF valve, of all-glass construction, capable of around 25 watts
output at 200 to 300 MHz. This I recall was used in the SCR522,
an American radio-altimeter which used radar techniques to bounce
signals off the ground thus providing, after suitable processing,
an aircraft's height. I may have one somewhere which I will include
here once unearthed.
See
more interesting valves>>