GS35b Data                 

Gs35b is a Russian Power triode available on various radio markets all over Europe for an acceptable price. Compared with an 3CX1500 / 8877 this tube is rather cheap and performing quite well. With 3kV on plate >1.5kW can be expected on 144MHz in a   grounded grid amplifier. A good design for a 144MHz PA (By DJ5RE) can be found in Dubus magazine 4/96.

Maximum Overall Dimensions

Length : min 173 max 177mm
Anode Diameter : min 99.7 max 100.2 mm (Red copper) 
Grid diameter : min 59.5 max 60.3 mm 
Cathode Diameter : min 40 max 40.5 mm
Heater Diameter : min 25.6 max 26.2 mm
Weight : 2.8Kg

Electrical Characteristics

Heather is AC 11,9-13,3 V /  Typical is 12,6 V / 2,95 (+/- 0,3) A
Plate Dissipation 1500 W
Plate Voltage 3000 V
Plate Voltage max 6000 V (Pulse)
Plate Current 1.4Amp
Heating time > 1.5 minute
Grid Voltage min -400 V max +100 V
Required Air flow 1500 l/min
Grid Dissipation 26 W
FQ max 1000 MHz
Plate Temperature 200 degrees Celsius max !
Grid Temperature 120 degrees Celsius
Cathode Temperature 120 degrees Celsius
Grid current ??? mA (max ??? mA)
C (g-a) 4,5 (+0,5 -0,7) pF
C (c-g) 21,5 (+/- 3) pF
C (c-a) 0,12 pF

Svetlana 4CX800A/GU-74B

GU-74B (analogue of 4CX800A) is a high - performance ceramic metal tetrode with a plate dissipation rating of 600 W with forced air cooling. The excellent characteristics allow its use as a high gain grid-driven RF amplifier or in grounded grid service. As a linear power amplifier, the GU-74B will produce about 600W PEP SSB and 600W CW in any of the three modes: grid-driven, grid -driven passive input, and cathode- driven. Main characteristics: cathode voltage 12.6V, cathode current 3.6 A. Maximum frequency 250 MHz, plate dissipation 600 W, screen dissipation 15 W, grid dissipation 2 W. Maximum DC plate voltage 2200 V, DC screen voltage 350 V, DC grid voltage -150 V.