Data set 01
1959 Rogers
Published operating points and test conditions from this source.
SECTION 1
Triode
Characteristic
HeaterOrFilamentVoltage
20 V
HeaterOrFilamentCurrent
150 mA
Voltage Radio Detector Converter ·Heptode-Triode
20J8GM
Rogers 20J8 (GM) indirectly heated triode-heptode superheterodyne frequency converter with 20 V 0.15 A heater, common cathode and 8H octal base.
Directly heatedCold cathodeCommon cathodeDissimilar
- Sections
- 2
- Base
- 8H
- Socket code
- IO
- Base pins
- 8
- Nominal heater
- 20 V / 150 mA
Description
Triode-heptode converter for receiver frequency-changing service.
Socket description
International Octal
General specifications
Tube and section characteristics
Properties common to every published source and operating point.
Heater and base
- Base
- 8H
- Socket code
- IO
- Base pins
- 8
- Nominal heater voltage
- 20 V
- Nominal heater current
- 150 mA
- Parallel heater voltage
- -
- Parallel heater current
- -
- Series capable
- No
8H - Terminal pinout
Electrical assignments shared by every tube using this base designation.
No verified pinout is recorded for this base designation.
Section ratings
2 physical sections, each with unique specifications.
Section 1
Triode
X-ray radiationInterelectrode capacitances
- Transconductance
- 0.0023 S
- Amplification factor
- 15
- Max plate voltage
- 100 V
Rogers 20J8 (GM) oscillator triode: max oscillator anode voltage 100 V; max dissipation not legible. Oscillator characteristics at anode 100 V and grid -3 V: mu 15, gm 0.0023 A/V; oscillator current about 8.5 mA in documented converter arrangement. Oscillator grid resistor 50 kΩ, grid current varies with load (500/400/80 µA for specified impedance cases). Common cathode with heptode, triode grid internally coupled to heptode g3. Capacitance oscillator output-to-all 5.5 pF.
Section 2
Heptode
X-ray radiationInterelectrode capacitances
- Max plate voltage
- 250 V
- Max screen voltage
- 100 V
- Max plate dissipation
- 2.5 W
- Max screen dissipation
- 0.6 W
- Max cathode current
- 18 mA
Rogers 20J8 (GM) heptode mixer: maximum plate 250 V, screen 100 V, plate dissipation 2.5 W, screen dissipation 0.6 W, maximum total tube cathode current 18 mA (shared with oscillator). Typical plate 100/250 V, screen 100 V, conversion conductance 320/350 µmhos at rated bias; do not store as conventional gm. Grid1 minimum bias -1 V, typical converter oscillator grid resistor 50 kΩ and minimum peak oscillator grid voltage 25 V. Signal grid-to-mixer plate capacitance max 0.012 pF, input 5 pF. Top-cap heptode signal grid; 8H base.
Source-dependent data
Operating conditions by source
Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.