GU-74B Amplifier for HF, 50 and 70 MHz
Top-10
A GU-74B amplifier that covers 3.5–28 MHz and also works on 50 and 70 MHz. The 4 m band is rare in homebrew amplifiers.
Specifications
- Bands: 3.5–28 MHz (80–10 m), 50 MHz, 70 MHz
- Drive: 16–25 W
- Output: 650–700 W
- Gain: about 14–16 dB (calculated)
About the GU-74B
The GU-74B keeps its full ratings up to 250 MHz, so 50 and 70 MHz are well within reach. The page gives one output figure for all bands. On the higher frequencies a tube amplifier usually gives a little less than on HF.
On the air
70 MHz is open to amateurs only in part of Europe, and there is little commercial gear for it. On 50 and 70 MHz people work sporadic E, meteor scatter and tropo, while HF covers everyday QSOs, DX and contests.