Karin,
Did you report this RFI problem to the FCC?
Here's there complaint page:
https://consumercomplaints.fcc.gov/hc/en-us/requests/new?ticket_form_id=38844
The FCC may do little to respond, but if there are very few complaints, then
it's not an issue to them.
No or few FCC reports = No FCC problems.
73,
de ed –K0iL
Eddie Edwards
Omaha, NE
-----Original Message-----
From: RFI <rfi-bounces+eedwards=oppd.com@contesting.com> On Behalf Of David
Eckhardt
Sent: Monday, July 25, 2022 12:26 PM
And again and again and again and again,...........WHERE IS THE FCC? ? ? ?
? ? ! ! !! !! !! !!!
Dave - WØLEV
On Mon, Jul 25, 2022 at 4:40 PM Karin Johnson <karinann@tampabay.rr.com>
wrote:
> Hello Group:
> Given the recent discussion about HVAC systems and RFI, I am writing
> this to chime in on an issue that I haven't seen on this reflector. I
> have had a brief discussion with another ham that has the same type of
> system, manufactured by the same vendor. His experience is similar to
> mine. He went a step further than I did and placed many type 31
> toroids on the 240 volt power feeding the compressor, but did not see
> any decrease in RFI.
> Now to the details.
> About two years ago I had to replace my HVAC system. I wound up
> having a Rheem model RP1748AJVCA unit installed. This system uses a 3
> phase motor in the outside compressor unit. The 3 phase motor is
> driven by an inverter that is housed in the outside unit enclosure.
> It is bonded to the enclosure via its mounting mechanism. The control
> interface from the thermostat and air handler is via RS-485 two wire
> communication which is routed along with the 24VAC power voltage for
> the outside electronics. Suffice to say this is an evil system with
> regard to RFI. The initial installation did not have the
> thermostat/control wiring replaced with shielded type. I had the
> installer come back and replace the wiring with shielded type wiring.
> This helped a bit with the RFI. I also installed type 31 toroids on
> the control wiring at the compressor and also at the air handler.
> This simple solution knocked the RFI down about only 6 dB. Note the
> RFI is most pronounced from about 4 MHz to 18 MHz. The remaining RFI
> is caused by the inverter running the 3 phase compressor. The noise
> floor increase due to the RFI is about
> 20
> dB, between the compressor being off and the compressor being on.
> Some time ago I believe I had posted a Google Drive link to some
> documentation I developed showing the spectrum analyzer plots taken
> with the system off and the system on. I might note that the power
> feeding the compressor inverter control board does have some internal
> filtering, by using toroids of unknown characteristics to me. Along
> with a substantial filter board, which appears to be a common mode
> filter mounted inside the metal enclosure of the outside compressor
> unit.
>
> My intent of this post is to simply inform folks to be aware of newer
> HVAC systems that use 3 phase inverters to drive the compressor motor.
> I have done a bit of design work to implement a possible solution to
> the RFI but its cost is prohibitive at this point in time. I would
> also have to dis-assemble the filtering boards and components on the
> outside compressor unit. Probably voiding the warranty.
>
> So in conclusion, folks, please do your homework and due diligence to
> investigate what type of technology the new HVAC system is going to use.
>
> Regards,
> Karin Anne Johnson P.E. K3UU
> Palm Harbor, Florida
>
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--
*Dave - WØLEV*
*Just Let Darwin Work*
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