The 5 power amplfier kit form box73.de was build and mounted on top of the enclosure.
It has a big heatsing so it will stay cool during wspr/qrss operation.
I have also mounted a switchable lowpass filter near the PA. I still have to wire it to the bandswitch.
To drive this amplifier I made a two stage amplifier using mar-4 amplifiers.
A single mar-4 did no provide enough power gain to drive the amplifier. Output power was 1 watt on 80 meter and 0.5 on 12 meter. So I have added another one. Now the gain is more than enough. Actually attenuation is needed to prevent overload.
The plan is to make an ALC circuit using a voltage controlled attenuator. Pin diodes will be used in the attenuator. I have just ordered some.
