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ID = 17139
Great Britain (UK)
Brand: MO Valve Co. Ltd.; GB
Developer: MO Valve Co. Ltd.; GB 
Tube type:  Transmitting Triode, air cooled   Text 
Identical to E1232 = 4C27 = NT99
Similar Tubes
Normally replaceable-slightly different:
Other class quality (otherwise equal):
Successor Tubes NT99   CV1256  

Base Wires Sidecontact and top contact.
Was used by Radar
Filament Vf 6 Volts / If 6.5 Ampere / Half indirect / Specified voltage AC/DC

Given the MOV company's experimental type number E1232, this tube was one of the first "micropup" using oxide-coated unipotential cathode. It was a pulsed triode and was designed by the GEC-MOV Hirst Research Center at Hammersmith, near Wembley, outside of London. According to Sir Paterson, its design had already started with considerable difficulties in May 1940. Certainly it was influenced by the parallel work of E.C.S- Megaw on the use of oxide-coated cathode in his E1189 magnetron, to drametically increase emission. Volume production started from September 1940.

It was made in large quantities by GEC-MOV and also in other countries, including the Canadian Rogers for REL and the National Union Tube Corp in the US. Given the British Navy designation NT99, it was mainly used in airborne radar. It was used in the AMES11 600 MHz mobile ground radar by the RAF and in the naval fire control radar type 284 at the same frequency. It was also used in the A1 radar, operating at 200 MHz. While it was a small tube, it could operate at around 50 kw.

Dimensions (WHD)
incl. pins / tip
x 133 x 52 mm / x 5.24 x 2.05 inch
Weight 197 g / 6.95 oz
Information source Taschenbuch zum Röhren-Codex 1948/49   
The Saga of Marconi Osram Valve   Pages 260 & 265
E1232: John Dodgshun
John Dodgshun

More ...
E1232: Manufacturer's Literature
Emilio Ciardiello

E1232: Manufacturer's Literature
Emilio Ciardiello

More ...

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