Curing RFI in the shack

I have been suffering from the dreaded RFI in the shack. I knew this because every time I keyed the transmitter, my digital clock would flash and my computer would play up or even shut down. Something had to be done.

After much talk with locals VK4CBW Wallace and VK4ZW Ray, I decided to get back to basics and start from scratch. I rebuilt the earthing system to ensure the connections were good, I removed the two external speakers I had rigged up and I removed the antenna switch that wasn’t grounded. This didn’t cure the problem.

Then I installed a 4:1 balun (thanks Wallace) and removed my G5RV and replaced it with a 20-10m dipole that I had shipped in from the US. Much better but still some RFI on one or two bands.

I then made a current choke by winding five turns of coax in a circle 8 inches in diameter at the feed point to the balun, which I mounted just outside the window to the shack where the coax enters. This did the trick.

The choke and LDG 4:1 balun outside the window of the shack.


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