Archive for June, 2012

HF Amplifier 50W 160M-15M

Wednesday, June 13th, 2012

My low cost  amplifier has been modified yet again.  I added a different filter board so that the amplifier will work from 160M through 15M.  The previous version had a home brew filter board covering 80M, 40M, 30M, and 20M.  Instead of re-doing the filter board to include more bands, I decided to go with the following filter board from HF Projects:

HF Projects – Low Pass Filter

Below is an image of the filter board (right-side) and the Arduino amplifier controller (left-side):

50W Amplifier

50W Amplifier

I found that the amplifier started to loose its efficiency above 21Mhz. I also had some issues with the COR/PTT board causing self oscillation; I went with a simpler solution.

Here is the schematic of the Arduino amp controller. Note that this is work in progress:

amp Controller Updated

The latest version of the Arduino amplifier controller  is found here:



PTT/COR Schematic Diagram

PTT/COR Schematic

PTT/COR Schematic