The FM300v2 is a broadband 300W amplifier for the FM broadcast band. We've recently managed to source a quantity of used BLF278 transistors at a great price, so have provided a reference design so that a low-cost, high performance amplifier can be constructed from the plans provided here.
This design is available as a paid download. Files will be available once a purchase is made.
- Broadband 300W FM broadcast amplifier operating from 87.5-108MHz
- Only 0.5-1W input drive required
- Microcontroller controlled on-board 2-stage thermal and SWR protection
- Fault output to power down exciter during a fault
- High efficiency - cool running
- High reliability - designed for years of continuous use at 100% duty
- Low harmonic content, suitable for direct connection to an antenna
- PCB Gerber files and full construction details with parts list provided as a digital download
- Power gain 25dB typical
- Gain flatness +/- 1.3dB
- Output power 320W typical
- Efficiency 68-78% (73% typical)
- Output power 270-345W (320W typical)
- DC Current consumption (main supply) 48V, 8.5-10.5A (9.5A typical)
- DC Current consumption (pre-drive) 12-15V, 1A
- Input power 0.5-1W
- Harmonic output -74dBc typical
We sell many of the parts to make this amplifier, and full details are provided on the parts list.
A limited number of PCBs are available here.
A programmed microcontroller for this design is available here.