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smcv.jpg (1013 bytes)smmini.jpg (1083 bytes)Spark gap and triggered gap tubes

Small thyratrons

trigatron.jpg (5041 bytes)trigpic.jpg (8682 bytes)STC 24B9 Trigatron. 6" high x 2" dia.

This gasfilled tube is normally covered in a protective 'sock' made from what looks like resin-impregnated bandage (as in right-hand picture), to prevent injury if the very thick glass shatters.

These devices were typically used as pulse modulators for high-power radar applications.

The table below lists specs for two other devices from the 1959 Ediswan catalogue.

Type Pout Gap Vpk  Pulse Length P.R.F Trig V Zl
  KW KV S Hz KV ohms
24B1 150 -7.4 0.25 2500 3.2 80
24C3 530 -13.3 1.0S 800 4.0 80

gap2.jpg (3345 bytes)gap1.jpg (3732 bytes)< Ferranti CC11 Triggered spark gap tube. (2" long)

< Small " dia. gas-filled gap tube, possibly argon or xenon as it glows blue-white when a high voltage is applied.

Marked V1507 10E/462

sylvgap.jpg (4321 bytes)Sylvania 1B26.

This unusual device has a very small needle gap in the round cavity at the bottom, visible through small glass windows either side. The gap is adjustable via a screw arrangement on the right, sealed with a cylindrical metal bellows arrangement. The bottom cavity is made of solid copper, 10mm thick - it's not clear whether this heavy construction is for thermal, mechanical or electrical (RF?) reasons.  Judging from the comments below, maybe it was designed to bolt in-line to flanges of a waveguide.

Thanks to Harry Visser for the following info : The 1B26 is a spark gap tube. It is used between the ring duplexer and the receiver section in a RADAR set. It is designed to keep the RF out of the receiver section. A ring duplexer is pretty good at isolation but not enough to prevent blowing the mixer diodes in the receiver. The terminal is used with some high voltage to make the tube more sensitive. My MG2 Hughes RADAR has one.

I've also received the following info from Manuel Carbonell: 1B26: Information from the book "Microwave Duplexers", Massachusetts Institute of Technology, Radiation Laboratory Series, McGraww-Hill
book Company, 1948. Developed by Westinghouse Research group and C.W.Zabel at the M.I.T. Radiation Laboratory Production by Westinghouse and Sylvania for radars at 24 GHz (1.25 cm band) during the WWII. These high resolutions radars were used to protect the USA-UK marine convoys from the german submarines, like the short wavelength (1.25 cm) can be used to detect the snorkel or periscope of submarines. And its small size permited to use it on the aircraft around the convoys. In the chapter 2 (Integral-cavity TR tubes) we can read about the 1B26: High-Q TR tube for 1.25 cm band, Pa=15 mW, Pt=25 mW, Ws=0.05 erg, recovery time at 3 dB=4 micro seconds, keep-alive voltage drop at 0.1mA=325-480 v. Gass composition: 10 mm Hg of H2 and 10 mm Hg of H2O in a volume of 18 cubic centimetres. Insertion loss=1.4 dB, Q=220, frecuencies from 23.42 to 24.58 GHz in a rectangular waveguide of 0.5"x0.25" inches, cavity diameter=0.25", cavity height=0.238", glass window=0.148" and body diameter=1.015". Turns of tunning screw: 0 at 23.25 GHz, 1 at 23.5 GHz,2 at 23.75 GHz, 3 at 24.00 GHz, 4 at 24.50 GHz and 5 at 24.75 GHz (aprox).

krytron.jpg (48862 bytes)The krytron is a high speed, high current gas filled tube. This tube can switch thousands of amps at thousands of volts. It is similar to a thyratron except that it is a 4 terminal device. The fourth terminal is a "keep alive" electrode that maintains a glow discharge in the tube at all times. This make the tube much faster and the timing more uniform. There is also a small amount of radioactive Nickel in the tube. The ionization helps further stabilize the propagation delay.

The  krytron was used on the early atomic bombs (and on other mundane applications like copy machine flash triggers) Next to this krytron is a hunk of "Trinitite", the green fused sand from under ground zero of the first atomic bomb test at Alamagordo, New Mexico. Still just a tiny bit radioactive.

Thanks to Neon John for this info.



00A15009.JPG (200076 bytes)Valvo Z50T cold-cathode trigger tube, used for interstage coupling and pulse-shaping in counter circuits using dekatrons. (50mm long) Datasheet

99C02011.JPG (247792 bytes)Telefunken sparkgap tube

Small Thyratrons

(Big thyratrons here)

thy2.jpg (15804 bytes)Three small gasfilled thyratrons - BT111, CV372, GT10 'gasfilled relay', used for TV and oscilloscope timebase circuits.

thy1.jpg (15152 bytes)Three larger devices - NGT7 mercury vapour device, CV1069, GEC GXU50

smcv.jpg (1013 bytes)smmini.jpg (1083 bytes)

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