TUBE 891-R

GENERAL DESCRIPTION


photo 891-R The 891-R is a three-electrode tube for use as a radio-frequency power amplifier, oscillator, Class A modulator, and Class B modulator. The construction of the filament permits operation from two-phase or single-phase alternating current, as well as from direct current, for all classes of service.

The plate of the 891-R is air-cooled by means of a special radiator which is fitted to the tube by the manufacturer. The plate is capable of dissipating 4 kilowatts of power, depending on the service in which the tube is used.

The 891-R can be operated at maximum ratings at frequencies as high as 1.6 megacycles and up to 20 megacycles at reduced ratings.
picture 891-R


TECHNICAL SPECIFICATIONS
ELECTRICAL
Filament
 Excitation
 Voltage per Section
 Current
 Starting Current
 Cold Resistance
Tungsten: Two-Section Type
Single- or Two-Phase AC, or DC
11 volts
60 amp
The filament current should never exceed 120 amperes, even momentarily.
0.031 ohm
Amplification Factor 8.5
Direct Interelectrode Capacitances (Approx.)
 Grid to Plate
 Grid to Filament
 Plate to Filament

28 μμF
19 μμF
2.5 μμF
MECHANICAL
Mounting Position Vertical, Filament End Up
Maximum Overall Length 22"
Maximum Radius 6-½"
Radiator Integral Part of Tube
Incoming Air Temperature 45 max. °C
Radiator Temperature 180 max. °C
Bulb Temperature 150 max. °C
Specifications may change without notice

THIS TUBE IS USED IN THE FOLLOWING SHORTWAVE BROADCAST TRANSMITTERS
Manufacturer Transmitter specifications Power in kW
RCA ET-4750 7.5


THIS TUBE IS AVAILABLE FROM
Manufacturer Rebuilder Distributor

Kennetron


PRICE LEVEL (US$)
1 2 3 4 5 6
0 - 10 10 - 100 100 - 1000 1000 - 10,000 10,000 - 50,000 50,000 - 100,000