The Ranger RCI-5Ø54DX-1ØØ has a external mounted 1ØØ watt RF amplifier, which has a very small fan for cooling. It may be enough for short transmissions, but for continious duty, a larger fan was needed.

I constructed a aluminum baffle for the fan and mounted it over the RF Amplifier heat sink, which did a nice job of cooling.

I removed the radio speaker, and the speaker holes let some fresh air into the radio interior.

During testing I discovered the TX driver area was heating too much, so I installed a heatsink on the rear chassis to cool it.

Also, the DC regulator chip was heating as much, and so a heatsink was mounted on the side chassis to cool it.

Now the radio would not look good under the dash of your car anymore, but it is ideal for a repeater transmitter.

The original RCI fan was removed from the slow thermal switch, and the new fan were connected to a RF switching transistor to turn the fans on.

The RF switching transistor was connected to the RF ampfifier driver circuit.

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