Dave, install ferrites on BOTH the input AND output.
Dave - WØLEV
On Wed, Jun 19, 2024 at 6:50 PM Dave (NK7Z) <dave@nk7z.net> wrote:
> Howdy,
>
> I have been chasing an RFI source that comes on and goes off on about a
> 7 minute cycle for 3 months now, I have suspected it was HVAC related by
> it's behavior... and timings of changes I have seen... Runs different
> at night, if an abrupt temp change occurs, a corresponding change in the
> cycle times, and lengths...
>
> It consists of broadband noise from 17 MHz, to 29 MHz. Worst at 24 MHz,
> not bad on 28 and 17 Mhz. It did not do this when it was installed, it
> has recently changed... He has had a lot of electrical work of late as
> well.
>
> Anyway, my neighbor had his vents cleaned, and let me know in advance...
> I started my S Meter logger last night, and ran it all night, and this
> morning... Seven Minutes after the HVAC people arrived, the RFI
> ended... I asked the tech about this, and he said he had just shut off
> the units... BINGO!!!!!!!!!!!!!!!! I asked him to text me as he
> brought up each unit... He did, and I now know what unit it is causing
> the issue...
>
> He also indicated they were having issues with the Mitsubishi inverter
> unit getting into people's LED lights, and cycling them... Sounds like
> it is really noisy on the power grid...
>
> Does anyone have any experience or a contact at Mitsubishi, or any
> suggestions on mitigation of this? I may start by having the HVAC
> people install some ferrites on the power to the inverter, at the
> inverter... But I want to contact Mitsubishi as well and see if they
> have an RFI kit...
>
> The unit model is SUZ-KA12NA, Service Ref: SUZ-KA12NAR1.TH
>
> --
> 73, and thanks,
> Dave (NK7Z)
> https://www.nk7z.net
> ARRL Volunteer Examiner
> ARRL Technical Specialist, RFI
> ARRL Asst. Director, NW Division, Technical Resources
>
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--
*Dave - WØLEV*
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