You can also look at intercomm systems with a monitor mode. Mine came from Radio Shack years ago and are still going strong. The advantage to this type of system is that it is transmitting over the electrical wiring between the house and the barn, so distance and intervening buildings are not an issue. I do pick up some static when any lights on dimmer switches are turned on, but since that doesn’t happen often and never at night, it hasn’t been a problem for me.
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