Hello. That’s right, these stakes disappear when you turn off the antenna. It’s very simple, I didn’t check this idea. Thank you Andy2. This signal comes from the ether. I put together an additional low-pass filter for the receiver. It is used to suppress frequencies above 30 MHz. I don’t use VHF anyway. The spectrum has become cleaner. Since next to me are 5 powerful VHF radio broadcast transmitters. This filter is required.