[RFI] Multi-Stage High Efficiency Air Conditioner Units

[James Jordan]

Very good comment. All wires are capable of being “transmitting antennas”, even that little thermostat or relay control wire. And ferrets do more good for hams than squirrels 😀😀


Sent from my iPhone

> On Feb 7, 2020, at 1:39 PM, <r55stan at gmail.com> <r55stan at gmail.com> wrote:
> 
> I was receiving some weak to moderate RFI from my Carrier HVAC unit.  I installed a line filter and ferrites on the power chord.  That helped, but I was not satisfied.  Then I installed ferrites on the cable to the thermostat and that reduced the remaining RFI to extremely faint on a SDR display.  Just about undetectable.  I consider that fixed.  The lesson for me on that project was RFI can get out of a piece of equipment on EVERY conductor that comes out of it.  I think we tend to only focus on the power chord because for most appliances those are the only wires connected to it.  My only other comment is a single pass through a ferrite probably won't reduce a strong RFI source enough.
> 
> Randy KQ6RS
> 
> -----Original Message-----
> From: RFI <rfi-bounces+r55stan=gmail.com at contesting.com> On Behalf Of James Jordan
> Sent: Friday, February 7, 2020 9:27 AM
> To: Kim Elmore <cw_de_n5op at sbcglobal.net>
> Cc: rfi at contesting.com
> Subject: Re: [RFI] Multi-Stage High Efficiency Air Conditioner Units
> 
> Can't be specific on HVAC units, but the Schaffer line filters, available in various amperage ratings from Mouser can be inserted in the power circuits. Mouser 631-FN2070[ampere rating]. I Use them on Pentair variable speed pool pumps at VP5 and they killed very nasty RFI from those motors. I would negotiate with an installer of higher quality units (Carrier, Trane) (Avoid the cheap Goodman, Coleman, etc.) that if the unit creates RFI that they will install appropriate line filters. We have a top end Carrier variable speed multi-stage unit and I'm not getting any RFI, but my hamshack is quite a ways from it in a detached garage bonus room so it's still possible some is being generated.
> Good luck.  The high efficiency definitely saves electricity.
> 73,
> Jim K4QPL
> 
>> On Thu, Feb 6, 2020 at 11:19 PM Kim Elmore <cw_de_n5op at sbcglobal.net> wrote:
>> 
>> My wife has been interested in increasing the efficiency of our air 
>> conditioner units. It seems that the only path to better efficiency is 
>> multi-stage/multi-speed units. I recall a lot of talk about the 
>> horrific RF noise these things generate. Does anyone know of RF-silent units?
>> 
>> Kim N5OP
>> 
>> --
>> 
>> Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, 
>> PP SEL/MEL/Glider, N5OP, 2nd Class Radiotelegraph, GROL)
>> 
>> /"A great second violinist plays second fiddle to no one." //– Robert C.
>> Marsh, Chicago Sun-Times./
>> 
>> _______________________________________________
>> RFI mailing list
>> RFI at contesting.com
>> http://lists.contesting.com/mailman/listinfo/rfi
>> 
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>