I had long wanted to build a very simple One valve (tube) Transmitter Most of my valve projects seem to grow in complexity as I built them but I have struggled hard to keep this one simple, I started out with the intention of using a good old ECL80 but it only having a single cathode limited me in my keying ideas, so not having any expensive audio valves such as ECL82/86 I used a 6AW8 an old TV Sync separator type which does the biz really well at about 4.5watts on 40mtrs CW

Here you can see the innards of the beast with its single valve, mains tranny smoothing caps and PA tuning, I have used my simple relay semi break in changeover idea which is excellent and makes it really easy to use and I've also added a side tone generator in the form of a piezo buzzer, And everything from the junk bin except the buzzer and chassis phono plugs that are used as a socket for the 10xj xtal total cost about £3 ($6)