It's amazing how a visible antenna can generate RFI, even if it's never been connected.
The "rule of thumb" when I was a kid was that a new antenna should be up for at least a week before it was used, so as to draw out complainers and enable the ham to deliver a preemptive strike by showing the coax unconnected.
I never bothered myself, since I was always too eager to get a new skyhook on the air. TV designs have changed, but I think six meter AM rigs did more to sell high-pass filters and FM rigs than any other single mode. I know a ham who was getting so many complaints that he built a varacter modulator into a Clegg 66'er, and drove it with a Turner +2 amplified mic. He used to burn out one varacter a month, because the +2 would put 9 volts on the mic lead when it was unkeyed, thus forward biasing the varacter for a very brief time. I think he figured it was a small price to pay to keep his neighbors happy.
73, Bill W1AC