Improvements to the 475KHz amplifier

Note the new, larger heat-sink and its position

Automatic antenna changeover circuit

I've made a couple of changes to the amplifier since I first reported on this project on 22 September 2014.
The mosfet has now been fitted to a larger ( 4.5degC/W ) heat-sink for better cooling, and repositioned to make device replacement much quicker and easier than before, should it again be necessary !
I've also added a circuit for 'rf voltage sensed' automatic antenna changeover switching which is a much more convenient arrangement than a manually operated  coax switch which I was using.

By the way, my 'countries worked' total on the 475KHz / 630m band has now risen to 14.