I have a noise problem on 40, 20, and 15 meters originating from the plasma TV I own. Turning on the TV raises the noise level by 2–4 S units, depending on the frequency. The TV is located below the antenna in the attic. The RFI also affects my outdoor antenna, to a lesser extent. My troubleshooting so far:
Things that don’t help
- Plug either the TV or the transceiver into a battery power station, while the other is on grid power.
- Wrap the TV’s power cable through a toroid core close to the TV (3–4 turns through an FT240-43).
- Same type toroid core at antenna feed point, 8 turns.
Things that eliminate the noise
- Power off the TV.
- Unplug the coax feed line from the transceiver.
Things that reduce the noise strength
- Unplug the antenna from the coax feed line. Noise is still present but quieter. Touching the center prong of the PL-259 coax feeds noise into it, as if I'm also an antenna.
My conclusion is that the TV is radiating RFI, without even the cables acting as antenna wires. Perhaps the metal mounting frame is acting as an antenna?
What might I do to eliminate the noise? Do I have options for this indoor attic antenna other than an expensive noise cancellation device?
FYI, the TV is an LG 60PB5600 60” Class Full HD 1080p Plasma TV