I’ve noticed two local movie theaters have zero 5G phone reception throughout the entire theater and I know this since it’s my local theaters so I’ve gone to each probably a hundred times since I started noticing this. My friends have also said the same thing, regardless of provider their phones don’t work in the theaters at all and yet when you go outside the front doors it’s full coverage again.
I know things that deliberately block cell phone signals are illegal but to me and my friends it’s no coincidence that somehow it’s impossible to use your phone in these unless your out the front door.
Do you mean no phone signal at all, or just no 5G signal? I’m a Verizon customer, and I was at a Verizon store today where there was no 5G signal, but I still had old-fashioned 4g LTE.
Coverage and signal behavior
Low- and mid-band 5G provide broad coverage and reliable indoor reception. High-band signals weaken rapidly and may lose over 100 dB when passing through common building materials.[43] Operators use beamforming antennas, small cells, and signal repeaters to extend range and improve indoor coverage.
There’s a store near here (a Kohls) where there is zero cell signal. Not data or voice. As soon as you get to the front vestibule it starts to improve and when you leave the store, five bars.
At the Shake Shack and the other smaller stores in the same shopping center, no problems.
Same with a Home Depot near here (but not that close to the Kohls) the same issue. The BJ’s Wholesale about seven miles away, same isssue.
I’m thinking something about the structure of those big box stores is interfering with the cell signal. I know deliberately putting in elements that block cell signals is a bit dodgy legally, but it seems impossible that a 100,000 square foot store can be such a severe dark spot surrounded by areas of good signal.
In each case I have never had trouble using my phone to pay at the registers, which are of course right by the front of the store. I’ve never paid by phone at the BJ’s, though.
As I learned when travelling abroad without cell service, you don’t actually need service or Internet to pay for things with your phone. Google Wallet and similar apps make your phone mimic your card, and it remembers how to do that once you’ve set your card up even if you have no internet or cell service (just like your physical credit card doesn’t need to be connected to the Internet, even if it has the tap functionality).
The machine at the register is presumably hardwired, or at least on their WiFi.
Your phone or card and the payment terminal each have a Near-Field Communication chip that they use to connect. No cell service is necessary for those devices to talk to each other.
Big box stores and theaters typically have a roof that’s very long steel girders over the large open area, and a steel roof. Not very RF-friendly construction.
I think @Atamasama is in the corporate infrastructure biz and can tell us bit about how they make sure cell signals reach into big office buildings. Simply not doing that might well be enough to kill most cell reception in big boxes.
When I pull up to the drive thru window at Tim Hortons I lose the sxm signal and my radio goes silent. It only happens at the window, one car length away it plays, when I pull away it plays. So strange.
A local high school has cell phone blockers. One must sign up for wifi access. Even their guest wifi feature requires admin approval.
Nope in Michigan. It’s what I’ve heard from adults who work there. maybe it’s a rumor and the building just has bad cell reception. But without signing up for wifi the phone is useless
I have a pole barn with a sheet metal facade (steel roof and steel walls). It’s a decent Farady cage; cell phone reception immediately goes to zero when I step inside. I put my phone in airplane mode to prevent the battery from draining.
I was at one time, now I’m in government but it’s really no different; big organizations all work the same more or less.
I know what my agency does is contract with a carrier (Verizon in this case) and set up signal boxes to provide a signal in a building that would otherwise be a dead spot. But it only works for Verizon; my personal phone is AT&T and it gets absolutely zero signal there. We might as well be a mile underground.
I guarantee it’s a rumor. Cell phone blockers are only legal for federal law enforcement activities and are very restricted.
The use of a phone jammer, GPS blocker, or other signal jamming device designed to intentionally block, jam, or interfere with authorized radio communications is a violation of federal law. There are no exemptions for use within a business, classroom, residence, or vehicle. Local law enforcement agencies do not have independent authority to use jamming equipment; in certain limited exceptions use by Federal law enforcement agencies is authorized in accordance with applicable statutes.
There’s something in between illegally blocking the signal and coincidence. It’s not that deliberately blocking the cell phone signal is illegal. From the FCC
The use of a phone jammer, GPS blocker, or other signal jamming device designed to intentionally block, jam, or interfere with authorized radio communications is a violation of federal law.
If you look up the actual law, it’s all about “devices”. Nothing illegal about deliberately constructing a building using materials ( like concrete and steel ) and a design (such as a large building with relatively few windows for the sq footage) that kills cell phone reception. I remember a time where you basically couldn’t get a signal in a casino or certain big box stores unless you were near the window. I assume they now have boosters/repeaters because I do get a signal now, and the buildings were not demolished and rebuilt.
Things that jam a cell phone signal, i.e., overwhelm it with radio noise, are illegal. Things that just passively block it, like walls, are not. And of course, some sorts of walls are better at blocking cell signals than others, and some sorts of buildings might deliberately choose to use such walls.
And if you once had coverage in a theater but now don’t, it might just be that the building has repeaters but management (wisely) decided to turn them off. There’s nothing illegal about that.
As @Chronos said, things that actively jam cell phone signals are illegal. Things that passively block cell phone signals are not illegal.
So what blocks a cell phone signal? The simplest thing is called a Faraday cage, named after this smart dude named Michael Faraday, who figured out that if you make an enclosed box out of some conductive material, the electric charge goes around the surface of the box and cancels out any fields inside the box. Or in simpler terms, the radio waves from a cell phone won’t penetrate a metal box.
Another principle is that a piece of metal with holes in it that are smaller than the radio wavelength acts just like a solid piece of metal to radio waves. This is why the door of your microwave oven has a screen that you can see through. Since the holes in the screen are smaller than the wavelength of the microwave radio waves, the screen acts just like a solid piece of metal and keeps all of the radio waves inside the box, where they cook your food, and doesn’t let the radio waves out of the box where they would cook you.
If you want to make your theater completely block cell phones, just line the walls with copper screens.
The thing is, the theaters might not be blocking cell phones intentionally. A metal frame building with a metal roof acts as a pretty decent Faraday cage, though you’ll usually get reception if you are close to the outside wall. Steel reinforced concrete is also pretty good at blocking radio signals.
If you want to make something like a theater, with a wide ceiling and no support beams to clutter up the view of the screen, a metal frame building is a really good choice, from a structural point of view. And that type of building is naturally going to block cell phone signals.
Maybe, but maybe not. A lot of modern cell phones can connect to wifi if they can’t get a cell signal, and most big box stores, casinos, and the like definitely have wifi. Some might also have cell phone repeaters. They are cheap enough to install these days.
FWIW, when I go to my main supermarket (which appears to be that sort of building), my cell signal gets to be very sketchy unless I’m near the front doors.