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This sections covers non RADAR vacuum tubes developed up to 1946
Frequency Band Terms used in this section
VHF and UHF POWER TUBES up to 1946
DOOR KNOB TUBES UHF tubes during WW2
Western Electric 388A UHF Triode Door Knob Tube Operates up to 700 MHz with 6 W powerLate 1930s. This is an example of a late 1930s UHF transmitting tube About 2.5" high.
As the operating frequency goes up the more susceptible likelihood of picking up interfernce or "strays" become.
Raytheon 717A UHF Pentode Door Knob Tube (made for Western Electric)Early 1940s. Often called the little door knob. About 1.5" high.
Shown in the lower center. The tube elements are turned 90 degrees in a horizontal position to operate at the higher frequency and minimize "strays". The tube on the left is the 388A. The other tube is a VHF tube type 832A.
VHF RF AMPLIFIER Transmiiting Tubes Design during WW2
RCA 832A and 829B Twin (2 tubes in 1 envelope) Beam Power Tetrodes (1940s)Operates up to 250 MHz
832A tube (about 3" high) 829B tube (about 4" high)20 Watt Power 45 Watt Power
RCA 833 / 833A RF Power Triode. (Late 1930s) Thoriated Tungsten Filament. In Class C operation can provide 1 Kw transmitting power at 30 MHz and at reduced drive up to 100 MHz. (unmodulated). Large vacuum tube (over 8 1/2 inches tall). Hefty filament- 10 Volts at 10 Amps. The older 833 had a more elliptical glass envelope.
HIGH POWER HF SHIP OR BASE STATION TUBES up to 1946
RCA UV-203 Power Triode (late 1921-1926) 50W Amplifier/Oscillator. (Stands 7.5" high)Operates up to 3 MHz
RCA UX-852 Power Triode (1927) 75W Amplifier/OscillatorOperates up to 30 MHz
ABOVE ^: The base pins are the filament connections while the wire leads are the grid (SMALL nipple) and plate (LARGE nipple) connections. Tube length about 8 inches
TYPE 860 Power Tetrode (1930s) 300W Amplifier/Oscillator. Unknown maker but based on construction and comparison with Sylvania design, likely made by Sylvania. Label on bulb probably rubbed off. Operates up to 30 MHz
ABOVE^ : Has the same connection setup and dimensions as the RCA UX-852. The long mesh you can see is the screen grid or second grid which designates it as a tetrode. A tetrode has two grids (grid and screen grid).
ABOVE ^: 833A Side View of the gray corrugated plateThe bottom pins are the filament connections.
BELOW: 833A Top view showing the grid structure and plate and grid cap connections.
BELOW: 833A Top view showing the grid structure and plate and grid cap connections.
Other HF Transmitter, Modulator and Amplifier Tubes
RCA Deforest 802 Power Pentode Amplifer/Oscillator 15W. Stands 5.75" high.
Operates up to 30MHz
Operates up to 30MHz
RCA 811 Power Triode for Modulator or Amplifier (1938)
Popular tube for amateur radio and industrial applications. The 811A is an improved version (1952) is popular today with tube stereo amplifier buffs.
Popular tube for amateur radio and industrial applications. The 811A is an improved version (1952) is popular today with tube stereo amplifier buffs.
RCA 803
Westinghouse 814
DeForest 802
RCA 803 Power Pentode (180 W) Amplifier/Oscillator. Stands 9" in heightOperates up to 20MHz
Westinghouse 814 Beam Power (Beam Tetrode) Amplifier/Oscillator. Stands 7.5" high.
RCA UX865 Power Tetrode (Early 1930s) 45 Watt RF Amplifier. Stands 6" high.
Operates up to 15MHz
Operates up to 15MHz
High Power Rectifier and Trigger Tubes
Western Electric 355A Mercury Vapor Thyratron (1930s and later)- Rated at 350 Volts at 16 A instantaneous current or 4 A average current. This is an unused early version. Note that the base is engraved with the brand and type number. Also the mercury is still housed in the bag under the plate housing. Used mercury vapor tubes generally have a metal tinge around the plate and mercury beads scattered around. Stands about 9 inches tall.
RCA 879 (2X2) High Voltage Rectifier for RF Equipment (1940s)Peak Inverse Voltage 12.5 KV sat 60 milliamperes
View of the Mercury capsule, perforated grid and plate (anode)
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