In NJ with PSE&G, some of their many many induction luminaires have a sort of piggyback plug on their photocell socket, with a cord leading to some sort of box on the underside of the arm that has an antenna facing down on it. Does anyone know what these boxes are for, or at least even seen these? I haven’t seen them on anything other than induction luminaires, but not all induction lights have them.

Here is a basic memory drawing I just made of the setup:
https://www.lighting-gallery.net/gallery/displayimage.php?pos=-258156

These are not exclusive to PSE&G lights. There are a ton of these around here, though they seem to be disappearing at a rapid rate.

I believe they are either one of two things.

A) they are "gunshot detectors"
B) they are a network device installed by a utility or telecommunications company.

EDIT:

They are likely old Ricochet Wireless boxes that simply haven't been removed.

Or, from Reddit:

It could be one of several radio systems.

This one is a Landis Gyr/Cellnet systems "router." It is probably for remote readout electric meters on 900 MHz, but the system forms a fairly generic data net that could be used for a number of functions, such as throwing switches to manage loads, reading system conditions, etc. They function as a wireless mesh node or star network.

It gets power from the standardized day/night photocell socket that's on most streetlights.

Photos

A very similar device by the same manufacturer: Photos (PDF) More Docs

Landis Gyr makes a number of different devices with that same basic enclosure. It's also possible that other manufacturers use the identical enclosure or a similar one. Ricochet wireless, a defunct wireless internet provider, used a similar system that is virtually indistinguishable by eye.

See an example of one by my old house here.

Very interesting, I suppose this could be one of many many things. I doubt it has to do with metering, because our town only switched to digital meters a little over year ago lol.

We do have plenty of reclosers around that might be able to operate wirelessly, that could be the case. I obviously wasn’t alive in 2001, so it could be an abandoned Ricochet Wireless box, but I guess I will never know for sure. I have yet to see one other than where I live, but I will definitely keep an eye out and see if they look any different.

Here's one in San Bernadino, Ca.
https://www.youtube.com/watch?v=kN_je2cUuYM

@Baked bagel 11
That definitely looks just like it, interesting.