Apparently, a Redditor on the r/AirRaidSirens page has found what is believed to be an Alertronic 5000 that is most likely still in place (although probably out of service). Here is the post: https://www.reddit.com/r/AirRaidSirens/comments/1lear7n/aca_alertronic_5000_found_the_one_piece_is_real/?utm_source=share&utm_medium=mweb3x&utm_name=mweb3xcss&utm_term=1&utm_content=share_button
Here are the coordinates the Reddit poster gave us: 34.9835206, -110.7158925
If you go into Google Street View at that location, and look towards the building to the northwest with the tower behind it, you can see the supposed Alertronic 5000 behind the building.