1kW 144 MHz amplifier with GS-35B vacuum tube
This is a short article presenting my first serious RF project. I started with electronics and HAM radio when I was 10 and since then it has been my main hobby. When I was finishing my high school, I had to do a final project and after some consultations with my friends I decided to build an RF amplifier and I was lucky enough that I had very clever and experienced people around me who were willing to help me with this, at that time, very challenging project. It was also very hard to find a supervisor at my high school as the amplifier works with a high voltage. At the time I was a member of OK1KZE radioclub and Mila OK1VUM (the president of the club) had already built several of those PAs and agreed to become my official external supervisor. Many thanks for the supervision and help! A long story short, I learnt a lot. One day I tried to switch on the main power source (those 3 big toroids that you can see in the photos) and something was seriosly wrong as I could hear some sound effects that really should not be there, so I switched it off immediately. The same day in the evening I told this problem to my friends (also HAMs) in the pub where we had regular meetings :) and we found that I had created a shorted turn in the transformer as both my chassis and the mounting bolt passing through the center of the transformer were conductive. It was easy to fix but I will never make the same mistake again. I think it is nice to see work that I did 10 years ago. I can remember that I spent all my savings from my summer jobs on this project and even my parents supported this project (a big thank you). It was a lot of work but I think it was worth the effort.
This is just a presentation of my project. This device can kill you and I don't accept any responsibility for your construction!
A short video from testing: https://vimeo.com/341928536