Remote Repeater Rebuild

It seems I’m always getting myself into projects that push the limits of my abilities as a grid-down communications operator. This past weekend was one of the recent highlights. One of our local Boy Scout reservations was having problems with their repeater and, while we were camping there this past summer, I had an opportunity to inspect the system and see if I could offer any guidance.

My thought was a commercial grade antenna at the top of a 150′ tower should be able to hear far better than it was hearing. If a signal cannot be heard, it doesn’t matter how powerful the transmitter is, the signal cannot be repeated; as my Elmer says, you become an alligator; all mouth an
d no ears.

During inspection, the antenna looked good, the hard line looked good and the SWR tested well, the repeater was operating, and the duplexer looked good. The glaring issue was the stuff-in-the-box at the base of the tower that connected it all together; many feet of RadioShack RG-58A/U with BNC connectors and way too many adapters converting N to SO-339 to BNC and back to N. These little not all that interesting parts of a radio and antenna system that are easily overlooked and quite often the items we cut corners on.

That said, the initial plan was to replace all of the wiring connecting the repeater stuff together and install a pre-amp on the receive side of the repeater. This would be done two hours from the closest place I could buy a suitable connector or tool to perform the service; that was the biggest problem to solve. What did I need to plan for to not only perform the desired work, but deal with any potential issues that could and would arise while performing said work? It’s all about being prepared for Mr. Murphy’s inevitable visit.

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As soon as I showed up to the base of the tower, I was glad contingency plans had been made, the power system was removed; no generator, no batteries, and no other power for over a mile from the base of the tower. Fortunately, I knew the inverter in the back of my truck was ample to heat up the soldering iron, and I also have suitable power and and extra 12v AGM battery that always travels with me when playing field radio.

The work was performed and the repeater can hear an order of magnitude better than it did. Though there were a few minor items I wish I had (e.g. low voltage wiring), there was enough redundancy build into my tools and supplies that the work was accomplished.

My key lesson learned is, don’t expect to ‘get things right’ when the zombies are coming, get out, practice, fail, learn, iterate, and practice more. Radio and comms support is as much an art as it is a science. This stuff isn’t easy and cannot be learned from a book, especially when field conditions are introduces and one small omission can be the difference between success and something far worse. Find areas you can help, network with good people, and practice your skills.

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