Enjoying the PA system, had some feedback for you! (and a bug)
Playing on the UN server (their Mod DEV confirmed they just use the vanilla PA system). I used the PA system for the first time, though I've watched videos where people used it, and were disappointed that they couldn't hear themselves speak. But it seems that might have changed as not only did i get the radio static, but I also heard my voice repeated a second to half-second later. That's the crux of the first issue behind my filing this bug report.
First Issue: My voice was repeated just late enough that I was speaking over myself, creating a strange effect known as "Delayed Auditory Feedback" that makes it impossible to form a train of thought, it wasn't just an echo, or a little reverb, it reminded me of someone trying to copy what you say as you're saying it, I think the delay needs to be shortened (dramatically) possibly?
Next the actual bug: After turning off the PA system, and removing the car battery, when I used my in game local voice chat (what I used to speak over the PA system with) I still heard the PA reverb effect. Luckily one of my listeners came by to collect his winnings (as I was having a radio give-away), and he confirmed that he 1. heard the broadcasting PA, and 2. did not hear it any longer after I turn off the PA (and removed the battery) and could still hear it in my headset. If i logged out, and logged back in, that would fix the bug, and I would no longer hear the reverb effect.