[RFI] Request for Comment (Rheem RP1748 A/C System)

Steve Dyer W1SRD w1srd at yahoo.com
Mon Nov 9 19:22:49 EST 2020

Does the shielding help prevent RF getting *into* the cable?
With these new 4 wire HVAC control systems I worry about RF getting in 
the system too.
> On 11/5/2020 2:18 PM, Karin Johnson wrote:
>> One toroid was placed at the Air Handler
>> inside the attic of my home, the other toroid at the Compressor outside
>> unit.  I know, some folks will probably say use type 31. 
> Yes, considerable research has shown that #31 is quite superior for 
> 160M and HF.
>  The type 43 is
>> what I had on hand and four turns provides about 20 dB suppression 
>> with this
>> wiring construction, as measured on my network analyzer.
>>> From some quick preliminary testing, it appears all of the RFI is GONE.
>> No more RFI from the unit while it is running at normal load.
> I strongly suspect that the same chokes placed on existing wiring (if 
> it was long enough to wind the needed turns) would also have solved 
> the problem.
> 73, Jim K9YC
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