Lately I see some that are cylinders and not rectangles . Is this a new design?
I’m assuming you mean the difference between the older, triangular towers made of struts (a lattice, self-supporting tower) as opposed to the newer pole-type towers (monopole design, some are very similar to the base shape of, say, a wind turbines tower). If so, then I’m not sure if it’s ‘new’, per se, but certainly, there are a variety of designs (even some concealed types that look like cacti or, I guess, trees in areas where there are trees or other structures).
I think the monopole types are cheaper to erect and maintain, and with the new systems needing more density of cellular antennas that’s probably a factor of why you are seeing more of those these days. I think the older towers were used because they were retreads of the older radio towers and there were a ton of them around and a ton of companies still making them, but with the need for so many towers, companies are building new designs that are more efficient and easier to maintain.
I don’t mean the big pole . I mean the antennas that are on top of the poles.
Horn antennas come in many different variations. do you see what you’re thinking of on this Wikipedia page?
I don’t know but maybe they’ve taken what used to be three 120 degree antennas that were separated on arms and bunched them together and put a single cover over them?
I suspect that it’s a single antenna instead of a cover over multiple antennas, but this is just a guess.
The newer cell phone protocols are much more intelligent and can talk to more devices simultaneously over the same bandwidth. With older systems they might have had three separate antennas effectively running three different isolated cells to handle high traffic areas, so that they could basically handle three times as many devices in that area. With newer equipment, one cell can handle more devices than all three of the older antennas combined could handle, so there’s no need to split up the cell for congestion.
So the old system might have had three directional antennas, and the new system has a single omnidirectional antenna.
Like I said though, just a guess. I don’t work on cell phone equipment.
There is one of these new pole antennas in a parking lot near me. It is just a straight round tube covered with appears to be gray plastic.
A while back they added another level at the top. First they added three back-to-back standard looking cell tower antennas, looking like each covered 120 degrees. A while later the antennas were then covered with more tubular gray covering.
I think these are 5G antennas, not positive about that though. They have a shorter range so they don’t need to be up as high. They may come as a cylinder even if there’s still an array of antennas buried inside. I bet the shroud is more for weather protection than anything. This is a pretty nice install:
This one not so much:
Is that what you’re talking about?
Oh, the sector antennas and probably the microwave uplinks if they don’t have wired infrastructure. Honestly, I haven’t seen anything that looks different to my eyes, though these days they usually have an array of sector antennas with more antennas per sector. That’s mainly because you need a lot more density for the new 5G stuff…but the antennas don’t really look all that different to me. I’d need to see a picture to see what you are talking about. It’s possible that what you are seeing is something else…maybe an omnidirectional antenna for public safety or could be part of the uplink or could even be part of the environmental protection (ice bridge or something along those lines) or specific for wind loading of the tower.
ETA: And, as engineer_comp_geek says, I’m not a cell phone radio engineer either. I have worked with microwave backhaul systems, but never on cellular systems, so I’m just guessing. If you have a picture I can probably take an educated guess though, FWIW.
Yes, the black cylinders at the top of the poles are 5G microcells.
There were always omnidirectional antennas. you just didnt notice them. They are up higher and cover the longer range.
What happens when you need more capacity at an omnidirectional only site ?
Well if you want to increase the number of users, you probably want more power.
So you start to add a 120 degree, for tripling the signal level. (all other things being equal.)
The rectangular antenna are also aimed down a bit to ensure it works for the ground near the antenna. For the omni, it might be a bit weak at the ground near it because its working in the plain … 360 around it … that plain is perpindicular to the omni’s shaft.
Modern antenna probably have multiple antenna elements, active and passive (passive means it doesn’t have an electrical connection.) built in to take ability away from low value zones to power up desired zones… eg totally turn off function upward. but enable function downward… so horizontal and down.