High Frequency Tubes

When operating in the realm of microwave and broadcast frequencies, electron tubes must take on unusual forms. The most common types of high frequency tubes are klystrons and magnetrons, which are used to generate microwave-level frequencies. Magnetrons are still widely used today, as the heat source in consumer microwave ovens. Klystrons still see use in broadcast transmitters for television and radio stations, as well as airborne and ground based radar installations.

 


Sperry 2K41
 

The Sperry 2K41 is a two-cavity mechanically tuned klystron used in various military radar and communications systems. This tube generates frequencies from 2660 to 3310MHz, with a filament voltage of 6V, beam voltage of 1200V, and a reflector voltage of 750V.

Sperry 2K41
CV3615
 

The CV3615 is a small British klystron packaged in a glass tubular envelope with a 4 pin base. This tube can produce frequencies in in ranges between 500MHz and 3.5GHz, and can be electrically tuned within a 6MHz window. Unlike many larger klystrons, CV3615 tubes were designed to be used with an external cavity; a cylindrical brass and bakelite enclosure which would fit over the top of the tube and seal against the two brass rings in the tube envelope. The length of this cavity would set the 6MHz tuning window, a mechanical plunger attached to a rack and pinion assembly allowed the length of the cavity to be changed as needed. The CV3615 tube was first introduced in 1948.

Of note to collectors is that some versions of this valve were packed in metal canisters, though later versions came in normal tube cartons.

More...

CV3615 Klystron Tube
Raytheon 2J51
 

The 2J51 is a tunable air-cooled magnetron with a range of 8.5Ghz to 9.6Ghz. Unfortunately this sample is missing several components, including the large semicircular magnets that would be clamped to each side of the tube. The 2J51 can generate microwave pulses in excess of 40 kilowatts.

Raytheon 2J51
Raytheon 2K33
 

The 2K33, made by Raytheon, is a mechanically tunable reflex klystron that operates in the 22 to 25 GHz band with a 40mW output. The tube is tuned by varying the length of the envelope through a flexible metal disk seal, a large mechanical lever arrangement on the top of the tube provides for this function. This unit lacks the bracket and tuning knob seen on some similar klystrons that is used for mechanical tuning, though the mounting flange is present and a knob could easily be installed.

Raytheon 2K33
Sperry 2K46
 

The 2K46 is a tunable air cooled klystron frequency tripler, with an output of 8.1 to 10 Ghz. The heater voltage is 6.3 volts and the output is rated at 1.5kV. The inputs and outputs are coaxial.

Sperry 2K46
Sylvania 5789W
 

This device was somewhat difficult to identify, but research revealed that it is a magnetron. The copper portions of this device that are mounted on either side of the waveguide are slightly magnetic, suggesting that the device originally had much larger magnets attached. The output of this tube is a fixed 34 GHz and the power requirement is around 14 kV. According to the book Tube Lore, this is the first commercially available US magnetron for the Ka band, and was released in 1949.

Sylvania 5789W
Klystronics 7238
 

The Klystronics 7238 appears to be a fairly typical metal-enclosed reflex klystron, almost surely electronically tunable. This tube uses a modified octal base commonly seen in small klystrons, in which one pin is replaced with a long waveguide. Unfortunately data on this device is scarce, and the specifications are unknown.

Klystronics 7238
Western Electric 730A
 

The Western Electric 730A is a non-tunable magnetron with an oscillating frequency of 9.375GHz, +/-30MHz. The 730A was used in military radar equipment. Note that the wooden base is part of the tube's original packing material, not an installable component.

Western Electric 730A
General Electric ZP-597
 

The GE ZP-597 is a large liquid-cooled magnetron, built in the 1940s. Little is known about this tube, but it appears to be a mechanically tunable device; a threaded collar allows the length of the cavity to be varied without tools. The tube has two pairs of liquid cooling connections, one of which is a simple copper tube that circles the outside of the device.

More...

General Electric ZP-597 Magnetron Tube

©2000-2018 Industrial Alchemy. All rights reserved. | Switch to mobile version | Contact |