A while ago, my HRO Sixty was on the bench being restored. Shortly after getting it up and running, I discovered a signal that was “all over the band” with seemingly unmodulated S9 carriers every 30.5 KHz. as indicated by my HP counter. It was on other bands too. I shorted the antenna terminals. The signal went away, not coming from inside the receiver. I looked all over my lab for some possible source that was inadvertently turned on, but found nothing. Nothing. I began to wonder where else in the house there could a source of such a signal, and could think of nothing. Nothing. To be sure, I turned everything in the shack off. Nothing.
To track it down, I one-by-one turned off every circuit breaker except the lab’s. Nothing. It wasn’t in the house. Concluding it was coming from the neighbor’s house - he’s a ham and who knows what he was playing with? With portable receiver, I went there. Nothing. But, the signal had become weaker so I went home, vigorously exercising my vocabulary of harsh words. A few days went by with the mysterious signal as strong as ever and my irritation increasing with the square of time. One day a prominent local radio amateur stopped in to ragchew. I was griping to him, and we once again went hunting with a portable receiver. WOOT! We found it!
The culprit was a microprocessor in my outside-the-house AC generator that was keeping its regulatory eye on my incoming AC. No amount of turning things on and off inside the house had stopped that processor from happily pumping its hostile little square waves and zillions of demonic little S9 harmonics into the air, with not the slightest interest in my poor HRO project. It didn’t help that the darn generator was only about four feet away from the workbench, separated just by an outside wall, though which I couldn't see. I think I’ll just give up ham radio and run away and join the circus!
al hart
w8vr
www.w8vr.org
