Hi,
I am confused by your question, can you restate it please?
I think I indicated that the variable speed unit was noisy. If you are
asking why the Carrier units are quiet, I would assume they have
filtering, as mentioned my another poster here, in this thread.
If you are asking why his changing the cycle times on the Mitsubishi
made things better-- he had it set to cycle on every 7 minutes, no
matter what the temp was, just to stir the air in his home. So every 7
minutes, I would get a 4 to 7 minute burst of RFI from the unit, then 7
minutes of silence, then another 7 to 5 minute burst of RFI, That cycle
would repeat, twenty four hours a day, seven days a week, three hundred
sixty five days a year, taking out over fifty percent of my listening
time on the mentioned bands.
Now that he has it set to on demand, (only when the temp is below the
set point does it start), it turns on far less than it did before, thus
giving me far more operating time on the named bands.
It still generates the same amount of RFI, but not near as often.
Sometimes it never even comes on during the day now... I used to tune to
any of the named bands and half the time, RFI was there, now most of the
time the unit is off, and no RFI. Does that clear this up?
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources
On 11/11/24 10:09, Steve London wrote:
Why would a multi-speed device be much quieter ? It's still changing
the frequency to control the motor speed, isn't it ?
73,
Steve, N2IC
On Mon, Nov 11, 2024 at 10:47 AM Dave (NK7Z) <dave@nk7z.net> wrote:
Think of a variable speed fan controller as an automatically
controlled,
dirty 500 watt square wave generator, connected to a long non twisted
wire, running a motor... They are quite noisy...
I have a neighbor that has one, (probably 70 feet from my
antenna), and
he used to run it 7 minutes on, 7 minutes off to clean his home
air. I
asked him if he could change that to as needed, and I now have 17,
15,
12, and 10 back, when it is not running, which is most of the time...
He has two Carrier units, and they make zero noise.
His Mitsubishi unit is the culprit in the RFI generation. The model
number is:
SUZ-KA12NA
The installer has no idea of what RFI is...
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources
On 11/11/24 08:40, Dan K2YWE wrote:
> Thanks Jack.
> Do your units have variable speed or multi-speed fan control?
>
> 73, Dan
>
>
> On Mon, Nov 11, 2024 at 11:10 AM Jack Ference
<jackference@gmail.com> wrote:
>
>> Hi Dan,
>>
>> Both Frank W3LPL I have had good luck with Carrier. He replaced
one unit
>> as nd replaced two a few years apart.
>>
>> I bonded the cabinet door to the sides, installed a powerline
choke on the
>> power to the blower motor and installed a coil of wire choke
around the
>> thermostat wires.
>>
>> I opted for one step down from the highest efficiency units so the
>> compressor had switched settings rather than variable settings
controlled
>> by electronic circuitry.
>>
>> Carrier was aware of my concerns and supplied the documentation
for the
>> fixes. They happened to be the same fixes I did on my first
unit replaced.
>>
>> Jack W3KX
>> Sent from my iPhone
>>
>>> On Nov 11, 2024, at 10:56 AM, Dan K2YWE <dan.k2ywe@gmail.com>
wrote:
>>>
>>> I'm need to replace my 25 year old HVAC with a new oil
furnace and AC
>>> system.
>>> EMIis a great concern. It's a small house and efficiency is of
little
>>> importance.
>>> What are the recommended brands and/or models?
>>>
>>> 73, Dan
>>> _______________________________________________
>>> RFI mailing list
>>> RFI@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/rfi
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