[Elecraft] Quiet Ductless HVAC System

[Dave Cole]

I have two goals in talking RFI to the vendors, and manufacturers...

1.  Make both the vendor, and manufacturer aware RFI issues may exist. 
This might help the next poor sod down the road, in that the RFI issue 
is no longer "new" to either vendor, or maker.

2.  Gets RFI on the table in the event there is RFI, I can say, we 
talked about this, and you said...

In my case, the vendor called the manufacturer prior to signing a 
contract, and the manuafacturer said no issues at all, RFI wise.  They 
were right.  The thing is dead quiet.

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 9:21 AM, Bob McGraw K4TAX wrote:
> 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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> 
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