> Zero emissions, silent, no illumination, etc.

Mostly silent. High voltage transmission lines may have a low-frequency hum. You have to stand directly under them to hear it though.

I was looking at buying a house with big transmission lines crossing over the property. It was a misty not-quite-raining day when I went to look at it, and you could hear the lines crackling and humming the whole time you were outside. I figured I’d have to give up ham radio if I moved there, ha.

Which you would, if they were crossing over your house. Probably not worse than many other mundane things though.

There's a high-voltage line that crosses over a park (with soccer fields etc...) near me, and you can hear it crackling whenever you're there. I'm sure it's a noisy radio environment.

Over time as some dirty coats the insulators, and on high humidity days some kind of crackling is clearly audible in a fairly wide radio close to the towers.

Also, transmission towers are usually the best lightning rods for miles in a given location, and it is fucking unsettling to live close to them during storms. Not to mention they are an eye sore.