Easy check. Since this occurred BEFORE you changed out the batteries, I'm sure you installed the new ones correctly. The simplest and IMO the FIRST thing I'd do is DISCONNECT your antenna that was installed by CW. IF your issues then go away, I would go BACK to CW and have them fix it, but with caution. They've been known to do sloppy work. That said, if disconnecting the antenna doesn't fix it, you've got a loose ground somewhere in your system. Very time consuming but pretty cheap fix...good luck,...Dennis