[Elecraft] Quiet Ductless HVAC System

[Bob McGraw K4TAX]

My take on this is "prepare to do some noise mitigation yourself."   
Jim, K9YC, has several good papers dealing with noise reduction and 
methods to accomplish same.   In general, adding correct type ferrite 
chokes to the AC mains and the control lines is, in general, good 
starting point.

Most HVAC companies are typically not versed in RFI technology and I 
wouldn't expect them to be.

73

Bob, K4TAX


On 5/27/2020 11:14 AM, Gary wrote:
> How did you find one that would agree to that? The 6 I've talked with all said pass as soon as I brought the subject up....
>
> 73,
> Gary kk0sd
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On Behalf Of Dave Cole
> Sent: Wednesday, May 27, 2020 8:45 AM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Quiet Ductless HVAC System
>
> Hi Albert,
>
> Here are a few suggestions...  When I added my furnace, I made it part of the purchase contract that there was to be no new RFI.  This makes the vendor very careful.  Tell them it is a showstopper, and they will be responsible for RFI removal if RFI comes with the new purchase.  Get it in writing if possible.
>
> Insist they call the manuafacturer and ask about RFI for the unit you are considering, and are there RFI kits for that unit, PRIOR to your purchase...
>
> Be careful assuming brand and model numbers will remain RFI quiet over time.  Vendors change parts, and circuits, within a fixed model number all the time...  What is RFI quiet today, may not be RFI quiet tomorrow...
>
> Take measurements first, before the install, and after install.  Use this process:
>
> https://www.nk7z.net/sdr-rfi-survey-p1/
>
> It is part I of III in a series on using an SDR to model your RFI environment.  Perform the tests, save the results, then run them all again after install...  I run a full sweep once a year here, and keep the results...  Also see my March 2020 article in CQ on this subject...
>
> Good luck, and good for you for looking at this early!!!
>
> 73, and thanks,
> Dave (NK7Z)
> https://www.nk7z.net
> ARRL Volunteer Examiner
> ARRL Technical Specialist
> ARRL Asst. Director, NW Division, Technical Resources
>
> On 5/27/20 4:09 AM, Albert Reynolds wrote:
>> Does anyone have suggestions for an RF quiet ductless, also  called a
>> "mini split" heat pump system. I am in need of a small (12000 BTU)
>> system for the ham shack. Comments from anyone who has used such a
>> system, or successfully mitigated RFI on a system would be
>> appreciated. Brand and model number would be highly appreciated.
>>
>>    
>>
>> Albert, N4AGG
>>
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