Monday, August 17, 2009

RF sloshing about

I had a report on the Canada-wide Aurora net (which I just bumped into while tuning around on 40m) that my audio was distorted at the peaks. The on air suggestion was that I might have RF getting into the radio. As I had so far experienced nothing but good reports, I was a little dismayed to hear this and immediately got to wondering what change I might have made that might have caused a deterioration. The main recent change to the station was the new V/UHF antenna, so I was a little worried that might be the cause (somehow!), but instead a quick radio check and experimentation on 40m with Adam VA7OJ revealed that it was the cable to my SignalLink USB box that was causing the pickup (or something in the box itself). A couple of ferrite chokes on the cable was reported to help a little, but the audio was only completely clean when this cable was unplugged.

More research is required as to a full solution here, and I'm somewhat at a disadvantage in the sense that my shack is directly beneath my R8, so I'm possibly even in the near field at 150 Watts peak output. Perhaps some grounding of the SignalLink box, and/or a better cable would do the trick.

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