DK9IP - A 23cm Linear Amplifier with water-cooled GS-15b

23cm Linear Amplifier with water-cooled GS-15b

by Winfried Kriegl DK9IP/KH7CD (October 2005)

This water cooled 1296 MHz amplifier was build around a cavity designed and made by Mats Bengtsson, KD5FZX.
It uses the russian GS-15b Tetrode with modified anode cooler and delivers up to about 350 W output without
thermal problems or de-tuning.
My amplifier is build into a 19" rack cabinet 48cm/19" wide, 30cm/12" deep (39cm/15" with external heat exchanger)
and 18cm/7" high, including power supply and water cooling components. The compact design and size provides an
easily transportable 350 W amplifier to be used with my portable SHF-contest setup.
The power supply provides HV switchable 1600/1800/2000 V DC, 32-39 V Ug1 and 350 V Ug2. It has regulated and
adjustable screen grid and control grid voltages and over-current protection circuits for anode and grid currents.
The water cooling system uses standard components (pump, heat exchanger) availabe for PC water cooling systems.
The tank contains 2 liters of distilled water wich is sufficient to keep the water temperature below 40° C (104° F) even
during long periods of short-interval CQing in CW.
Below are some pictures of different construction stages and the final product. Well - almost final. Still missing labeling
of the front and rear panels...

Thanks to Mats, KD5FZX for providing the cavity and modified tubes.