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RFI from MrCool Minisplit.

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by NX0R, Sep 2, 2021.

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  1. NX0R

    NX0R XML Subscriber QRZ Page

    I have an RFI problem on several 6m frequencies originating from my MrCool 18k BTU minisplit . The noise is present when the air conditioning is producing cool air, but when it cycles off the noise is gone.

    I've put snap on ferrite inductors on the cable going from the inside unit to the outside one on both ends.

    The RFI is worse on 50.313 , but is pretty narrow.

    Ideas on how to find and eliminate the problem?

    TNX es 73 Jim NX0R Hays, KS
  2. KA2RRK

    KA2RRK Platinum Subscriber Platinum Subscriber QRZ Page

    Finding it has been a success.

    To eliminate the problem, I think that a good solution would be to cut up card board from discarded boxes say in 16inches X 18inches, then with a good weather proof marking pen list your location and title the message " YARD sale". Hang these around your location on supplied utility poles like everyone else does. Now you need to find some other items to put in the yard that you don't want and pick the weekend for your sale...

    In three or 4 weeks summer will be over anyways...

    WN1MB likes this.
  3. KA9JLM

    KA9JLM Ham Member QRZ Page

    Eliminating totally may never happen, Because of how they are designed.

    Moving your antenna may be the best fix.

    Good Luck.
  4. KD9VV

    KD9VV Ham Member QRZ Page

    Snap ons are not particularly effective.
    Ferrite cores with the wires looping thru them is far better.
    Next, it may be i the ac motor itself (windings)

    Have you just run the fan w/o cool.?
    NX0R likes this.
  5. NX0R

    NX0R XML Subscriber QRZ Page

    THe compressor cycles on and off during cooling. The noise is present when the compressor is running, but not when off. I have not tried it yet in heat mode. The wires aren't long enough to loop, but I might try multiple ferrite snap on's .

    TNX 73 Jim NX0R
  6. WN1MB

    WN1MB Ham Member QRZ Page

  7. KA9JLM

    KA9JLM Ham Member QRZ Page

    I was going to buy one of these, Then deal with the RFI.

    There is going to be some noise from the PWM Inverter. Moving the antenna is going to be the easy fix. The instructions say try to orientate your antenna in a different position. :p

    The comfort one can provide outweighs the RFI. A lot less noise than my wife whining that it is hot in here. :oops:
  8. WN1MB

    WN1MB Ham Member QRZ Page

    That reminds me of a recurring theme in Mad Magazine: What They Say, and What It Really Means *

    When MrCool says: try to orientate your antenna in a different position, what MrCool really means is: we currently have no fix for our deficient, RFI producing design.

    * for the unwashed:
    KP4SX likes this.
  9. WN1MB

    WN1MB Ham Member QRZ Page

    And no follow up from the OP since September 8.

    Yep. This must be The Zed...
  10. AI5DH

    AI5DH Ham Member QRZ Page

    The generated noise is the VFD that controls the speed of the compressor. The VFD is a variable frequency inverter that runs the motor. You would need filters at the input and output of the VFD. A professional job only.

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