21-05-2022, 09:38 AM
We have a Fujitsu AOT30L outside unit feeding 4 inside blowers, and it generates S9+ noise across HF.
I tracked the source to wiring from a PCB to the motor, and fitted a string of ferrites to that cable. That cut the noise down to S7. I have been meaning to make up a substitute wiring lead that has a RF choke inline but haven't got around to it
The outside unit is at the other end of the house from the HF antenna and I did that deliberately, anticipating it may be a noise-generating issue.
All this said, when I researched units prior to buying someone told me their Fujitsu single outside unit feeding one blower did not generate noise.
I tracked the source to wiring from a PCB to the motor, and fitted a string of ferrites to that cable. That cut the noise down to S7. I have been meaning to make up a substitute wiring lead that has a RF choke inline but haven't got around to it
The outside unit is at the other end of the house from the HF antenna and I did that deliberately, anticipating it may be a noise-generating issue.
All this said, when I researched units prior to buying someone told me their Fujitsu single outside unit feeding one blower did not generate noise.
Damien
http://www.vk3rx.com
http://www.vk3rx.com