GMRS repeaters do not have to ID. The users of the repeater must ID when they use it. When I first became licensed, about 25 years ago, you had to designate on the application IF you were going to have a repeater, how many mobiles, how many portables.... also you had to designate which pair you were using for the repeater, your LAT/LON and calculate your ERP. You don't have to do any of that now. If the FCC needed repeaters to be "registered" they would still require that. Tower wise, mine is beside a barn on a hill, it's about 35 feet with a 18 foot ASP fiberglass stick on top. There was never a requirement for a site registration because we are under 200' tower height, and not in a flight path. There are TV antenna towers at 60 feet around here...so no issue there.