Noise 20 over S9, then gone abruptly for 45 minute

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Noise 20 over S9, then gone abruptly for 45 minute	Reply
by K3QS on April 10, 2004	Mail this to a friend!
Hello all, I’m in a new QTH, and with a temporary Vertical 40 – 10 M antenna in the back yard, I’ve been able to listen to HF with my temporary rig setup while I’m planning and setting up my new shack. I’m somewhat concerned by what I’ve heard on 40 M (my favorite) and other bands at reduced level. Periodically, like every half hour or hour, and lasting for 3-6 minutes, is a horrendous S9 +20dB noise very similar to the noise I’ve heard from the spark in the oil burner at some of my previous homes. It starts abruptly, stays constant in level, and disappears abruptly. It is strong enough to wipe out almost all signals. So far I’ve not snooped around the neighborhood with a RX, but I’m getting ready to start. Does anyone know, do the new high efficiency furnaces perhaps have a stronger ignition spark system than the old furnaces? The oil burner in this QTH is about 5 years old, and it is reasonable in its noise generation. Somewhere nearby, there is a generator of much higher magnitude. It seems to happen less frequently as the weather warms up, so I’m suspecting a furnace. Thanks for your ideas, 73, Doug

RE: Noise 20 over S9, then gone abruptly for 45 mi	Reply
by WB1AEX on April 16, 2004	Mail this to a friend!
It sure sounds like you have narrowed it down. The timing cycle sounds exactly what would be expected for a furnace motor with noisy/worn brushes. In my own house the old furnace was fairly quiet. When I replaced it about 5 years ago the new one proved to be silent, except during the first few seconds of ignition. When it first fires up there is short burst of noise that I can hear on the HF bands and the BC band. I am sure it could be cured easily with .01 bypasses. When the brushes are worn on any of the pump motors or the furnace blower/injector motor they can get quite noisy. I suspect that if you can track it down with a portable the owner might appreciate the tip that his/her furnace might need attention. Most likely they are hearing it too on their BC radios.

RE: Noise 20 over S9, then gone abruptly for 45 mi	Reply
by N0GBR on October 23, 2006	Mail this to a friend!
I wonder if you ever figured out you RFI problem. I have recently had installed a new high efficiency variable rate dc fan furnace and the noise is awful. Is that what your issue was?? tnx, John N0GBR

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