The Beginning Phases of Construction

Heat sink drilled with some parts mounted.

The source bus ready to be soldered to the MOSFET sources.

Good closeup of a module showing the drain bus and shunt capacitor.

The drivers are mounted, ready to be soldered.

Drivers soldered to gate pins, driver bypass caps, drain transzorbs.

Further into the construction

Closeup of the drivers, terminating resistors and connections to the driver input pins.

Starting the output transformers (1:1 ratio).

The secondary winding is run through the cores first.

The primary windows are cut and bent. They should all be exactly the same.

The primary windows are inserted into the cores to form transformers.

A good shot showing all of the transformer connections. It is very important for the transformers to be connected properly to ensure proper combination of the class E modules.

Finally Assembly and Completion

Closeup showing the shunt capacitor bandswitch relays. The shunt capacitors are soldered directly to the relays, and the relays are soldered to the drain bus through a piece of copper. This is done to minimize the inductance in the shunt capacitor path to ground.

In my implementation, each module has its own 12V switching regulator for the drivers. You do not have to build it this way. You can use a single 12V 15A supply or thereabouts, and it will work just fine. The 12V supply for the drivers may be left on all the time. It does not need to be switched off between transmissions, and is probably best left on.

The underside showing the driver power supply transformers.

View of the RF deck from the top. The 160 meter coil is to the right, and the 160 meter coil relay is visible just underneath the 160 meter coil.

Another view of the completed RF deck. The variable capacitor to the far right is an additional loading capacitor in parallel with the main loading capacitor.