Four GU-50 tubes power amplifier
Top-10
Amplifier build on four gu-50 tubes which is used for wideband power amplification at frequencies up to 100 MHz in RF equipment.
For more information see GU-50
Input power from 35 to 40 Watt.
Output power up to 300 Watt.
Frequency band from 3.5 to 28 MHZ
Four GU-50 tubes covering 80 to 10 m. About 35–40 W of drive brings it up to 300 W out.
Specifications
- Tubes: 4 × GU-50
- Frequency range: 3.5–28 MHz
- Drive: 35–40 W
- Output: up to 300 W
- Gain: about 8 times, roughly 9 dB
About the GU-50
The GU-50 is a glass transmitting pentode with an anode dissipation of 40 W. It is the Soviet counterpart of the German LS50. One tube on its own gives a modest output, so hams usually put several in parallel to get into the few-hundred-watt range. The tubes are cheap and still easy to find.
On the air
With a 100 W transceiver you have to turn the power down to 35–40 W before keying the amp. A QRP rig of a few watts will not drive it fully. On the air the 300 W gives about 5 dB over a barefoot 100 W rig, which helps on 80 and 40 m at night and on 20 m DX.