On 1/16/2018 8:29 AM, John Huecksteadt wrote:
Last year my neighbor bought a new Lennox "Green" A/C. That simply
means the fan on the outside unit is variable speed. The local Lennox
shop replaced the DC unit with one that was supposed to fix the
problem. Didn't. He claims the whole unit is run on DC now. Ongoing
issue. Horrible noise on several bands.
Variable-speed motor controllers are a well-known source of RF noise.
The mfr should provide a suppression kit. A good ferrite choke on the
drive cable between motor and controller may also fix it. See my website
for choosing the ferrite and winding the choke, following guidelines for
coax of size comparable to the cable you're choking. Study the Ham's
Guide to RFI and Building Contest Scores by Killing RX Noise.
73, Jim K9YC
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