[RFI] Interference from AC units

Jim Brown jim at audiosystemsgroup.com
Sun Aug 28 07:00:29 PDT 2011

On 8/26/2011 5:08 PM, Richard Battles wrote:
> i had the installer
> put ft-240-43 ferrite cores on the wires leaving the unit to the wall
> thermostat, outside unit, and what ever else.

That is VERY unlikely to have had any effect on RFI on the HF bands. It 
MIGHT have had some small effect on 2M.  For ferrites to do anything at 
HF, we must wind multiple turns around them.

In other words, if your system is RF-quiet, it was built that way.

73, Jim Brown K9YC

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