Club Portable Repeater
The club’s old portable repeater developed an intermittent problem so we’ve decided to replace it using slightly more modern technology. After a generous and appreciated donation by VK3TIM of the key parts for our new repeater, the new system is almost complete.
A great deal of time was spent thinking of the optimum construction. We wanted something that was light, compact, robust and reliable and that could be managed easily by one person.
After a test-run of the repeater, the transmit modules both got too hot to touch, even without any form of case, so cooling was considered essential.
Ross played with different arrangements and finally settled on the version presented here. The parts all form a “wind tunnel” with the transmit radios heatsinks exposed to the greatest airflow. A fan at the bottom blows air up through the tunnel, cooling the radios. Hot air exits out the top through a 10mm gap between the transparent lid and the case, and after an hour of solid use with the fan running, the transmitter modules were a comfortable 38 degrees.
The clear lid lets the contents be visually checked for any obvious problems, as well as being able to see the radio status on the included control head.
The diplexer is mounted such that most of the connector is protected with just a few mm exposed.
With the fan at the bottom of the case (albeit with a fine mesh guard), in order to reduce dust ingress, the whole repeater is designed to sit on top of the sealed battery with spacers to ensure adequate airflow, and keying tabs to it remains comfortably located atop the battery to ensure a good clean air supply. Weighing in at just under 8kg it’s easy to carry with the attached adjustable shoulder strap.
With luck, one of the upcoming events will give it a good workout!
Assembly showing the highly modular “wrap around” construction (temperature switches yet to arrive 😁
Photos 11 and 10; The mast was not fully extended, but is indicative and shows the repeater sitting on the battery. (pic11)
This is before the case was painted (thanks Erwin) to show how compact and portable the entire setup is now. (pic10)
Last two photos – 12 and 13: The last two pieces. Thermal switches done for fan control and Anderson Powerpole mounted and connected.