MC-ARES/RACES

The noise problem currently being experienced by the K6JE repeater, is a very common problem for repeaters.

There is a chain link fence at the base of the tower we currently have our active 2m antenna on. The fence surrounds the anchor point of several guy wires for another structure. Our 1/2” hard line and messenger line were both rolled up and lashed to the chain link fence when we weren’t using it.

We removed the coax / messenger line roll and strung it back across the lot between the tower and the KSBW structure. When we removed the roll from the fence, we may have inadvertently loosened the fence around the guy wires that allows it to wiggle in windy conditions up there.

When there’s loose metal near a repeater antenna, the TX signal paints the loose metal with RF causing arcing as the metal surfaces move by wind or other vibration. The arcing created by the RF hot metal causes the creation of broad band RF noise (emissions) that you hear in the receiver as scratching or static sounds.

So we need to go back up to the site and:

1 Re enforce the chain link fencing around the guy wire anchor by using some new chain link fence wires to tighten any fence that may be rubbing when the wind blows.

2 We need to take the messenger line wire that’s holding up the 1/2” hard line, and hard secure it to the KSBW cable run grid structure to eliminate any possible rubbing.

That should stop the wind related noise problem. Hopefully we can get up there next week with good weather, and get things clamped down.

73,

Bob Wiser, K6RMW

President, FPRA

EMAIL: [email protected]

CELL: 831-840-8228