# If a Court Room can tell if my cell phone is on, why can't an airplane? **URL:** \ **Category:** Factual Questions\ **Created:** [August 18, 2010, 7:33pm UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658 "2010-08-18T19:33:02Z")\ **Posts on this page:** 17\ **Page:** 2
**Author:** ![ZipperJJ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zipperjj/32/211_2.png) [@ZipperJJ](https://boards.straightdope.com/u/ZipperJJ)\ **Post date:** [August 19, 2010, 3:17am UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/21 "2010-08-19T03:17:21Z")
[quote=“Gary “Wombat” Robson, post:12, topic:550658”] > [@Caffeine.addict](#): > > One possible explanation for how they can tell is that a live cell phone can screws with the court reporter’s equipment. Definitely not. I was in the business of designing and building court reporting equipment for ten years, and cell phones definitely do not interfere. [/QUOTE] Man, I LOVE when this sort of thing happens on the Dope 🙂 ---
**Author:** ![amarone](https://avatars.discourse-cdn.com/v4/letter/a/e0b2c6/32.png) [@amarone](https://boards.straightdope.com/u/amarone)\ **Post date:** [August 19, 2010, 3:28am UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/22 "2010-08-19T03:28:11Z")
> [@Buck\_Godot](#): > > Anecdote: > > I was in a plane a year or so ago in which a little after telling everyone to turn off their phones, the flight attendant made an announcement something like “There are 3 cell phones still on.” No idea whether she was lying or not, but perhaps they can detect them and just don’t care. Probably lying, and probably making a reasonably correct estimate. I try remember to switch mine off but I know I have failed on occasion. If I am typical of the flying public, then there are indeed 2 - 8 phones still switched on (depending on the size of the plane). ---
**Author:** ![taffygirl](https://avatars.discourse-cdn.com/v4/letter/t/b5a626/32.png) [@taffygirl](https://boards.straightdope.com/u/taffygirl)\ **Post date:** [August 19, 2010, 3:32am UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/23 "2010-08-19T03:32:10Z")
How many times have you been in a meeting that started with a reminder to turn off cell phones, only to have someone’s phone go off during the meeting? I bet it’s happened in 80% of the roughly one squillion meetings I’ve been to. While a couple of people may think they’ve turned off phones when they haven’t, I think the majority who leave phones on just want to sneak out some text messages. Saying, “Someone still has a cell phone on!” may just be a pretty safe bet, and if people think, “Ooo! They can TELL?” they’re more apt to turn off their phones. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [August 19, 2010, 9:12am UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/24 "2010-08-19T09:12:08Z")
^ Well, until someone accidentally leaves theirs on, and realizes they can’t. ---
**Author:** ![KinkiNipponTourist](https://avatars.discourse-cdn.com/v4/letter/k/e9bcb4/32.png) [@KinkiNipponTourist](https://boards.straightdope.com/u/KinkiNipponTourist)\ **Post date:** [August 19, 2010, 10:15am UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/25 "2010-08-19T10:15:02Z")
[quote=“Gary “Wombat” Robson, post:12, topic:550658”] > [@Caffeine.addict](#): > > One possible explanation for how they can tell is that a live cell phone can screws with the court reporter’s equipment. Definitely not. I was in the business of designing and building court reporting equipment for ten years, and cell phones definitely do not interfere. [/QUOTE] I use wireless interpreting equipment (Panasonic’s Panaguide system) and get horrible interference from cell phones. I wonder what the difference is? ---
**Author:** ![qpw3141](https://avatars.discourse-cdn.com/v4/letter/q/6bbea6/32.png) [@qpw3141](https://boards.straightdope.com/u/qpw3141)\ **Post date:** [August 19, 2010, 10:28am UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/26 "2010-08-19T10:28:17Z")
> [@amarone](#): > > > [@Buck\_Godot](#): > > > > Anecdote: > > > > I was in a plane a year or so ago in which a little after telling everyone to turn off their phones, the flight attendant made an announcement something like “There are 3 cell phones still on.” No idea whether she was lying or not, but perhaps they can detect them and just don’t care. > > Probably lying, and probably making a reasonably correct estimate. I try remember to switch mine off but I know I have failed on occasion. If I am typical of the flying public, then there are indeed 2 - 8 phones still switched on (depending on the size of the plane). I was on a flight to Egypt some while ago and all the usual announcements were made about turning off mobiles. The flight proceeded normally until, as we descended and the aircraft came into range of Cairo’s base stations, the overhead storage erupted into a cacophony of mobile ring tones. Obviously a large number of people on the flight assumed that ‘not using mobile’ == ‘turning mobile off’. Of course the **really** interesting thing to note is that despite all these mobiles being switched on and desperately trying to attract the attention of a base station, no harm had come to the flight. The same thing happens to a much lesser extent on most flights so mobiles evidently aren’t the threat to aircraft operation that they are made out to be. ---
**Author:** ![Mops](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mops/32/16494_2.png) [@Mops](https://boards.straightdope.com/u/Mops)\ **Post date:** [August 19, 2010, 10:45am UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/27 "2010-08-19T10:45:50Z")
My cell phone (GSM) generates a characteristic ‘barap, barap, barap’ interference on my home landline phone - not continually, but from time to time as it tells the cell tower it’s there. I suppose the clerk may have listened in to some recording equipment and recognized some characteristic sound. ---
**Author:** ![bardos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bardos/32/1069_2.png) [@bardos](https://boards.straightdope.com/u/bardos)\ **Post date:** [August 19, 2010, 11:41am UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/28 "2010-08-19T11:41:29Z")
If there were any genuine threat to aircraft stability/security from mobile phones, they would not be allowed on planes. Imagine: Seven terrorists board an airplane and at the same time over the Atlantic Ocean all turn on their phones at once. and… nothing! ---
**Author:** ![Gary\_Robson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gary_robson/32/3448_2.png) [@Gary\_Robson](https://boards.straightdope.com/u/Gary_Robson)\ **Post date:** [August 19, 2010, 2:44pm UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/29 "2010-08-19T14:44:02Z")
> [@KinkiNipponTourist](#): > > [quote=“Gary “Wombat” Robson, post:12, topic:550658”] > > Definitely not. I was in the business of designing and building court reporting equipment for ten years, and cell phones definitely do not interfere. I use wireless interpreting equipment (Panasonic’s Panaguide system) and get horrible interference from cell phones. I wonder what the difference is? [/QUOTE] Court reporting systems consist of a computer system, specialized software, and a stenotype keyboard (possibly wireless). Interpreting equipment (voicewriting, audio recording, video recording…) is a whole different animal. ---
**Author:** ![Jackknifed\_Juggernaut](https://avatars.discourse-cdn.com/v4/letter/j/9de053/32.png) [@Jackknifed\_Juggernaut](https://boards.straightdope.com/u/Jackknifed_Juggernaut)\ **Post date:** [August 19, 2010, 3:28pm UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/30 "2010-08-19T15:28:39Z")
> [@nuggz](#): > > > [@Jackknifed\_Juggernaut](#): > > > > A few years ago, I was in court for my divorce. The clerk asked everyone to turn our cell phones off. I had just gotten a new blackberry, and assumed it was off. In reality, I only turned the display off and didn’t know that it was still on. Shortly thereafter, the clerk announced that someone’s phone was still on and asked all of us to check our phones again. I finally and embarrassingly figured out that it was mine. > > > > But I’ve flown a couple of times with my phone on inadvertently. How come the airplane couldn’t detect this? > > Did you have your bluetooth on? She might have done a bluetooth scan. No Bluetooth. Also, this was a Canadian courtroom, if that changes anything. ---
**Author:** ![Rhodes](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rhodes/32/273_2.png) [@Rhodes](https://boards.straightdope.com/u/Rhodes)\ **Post date:** [August 19, 2010, 4:10pm UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/31 "2010-08-19T16:10:34Z")
Some cell phones periodically cause interference on some speakers. My iPhone doesn’t do it, but all of the cell phones I’ve had in the past have made computer speakers and baby monitor recievers emit a loud distinctive buzzing sound when I am about to recieve a SMS or call, or just to tell the cell tower “here I am”. ---
**Author:** ![Rhodes](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rhodes/32/273_2.png) [@Rhodes](https://boards.straightdope.com/u/Rhodes)\ **Post date:** [August 19, 2010, 4:19pm UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/32 "2010-08-19T16:19:37Z")
> [@Rhodes](#): > > Some cell phones periodically cause interference on some speakers. My iPhone doesn’t do it, but all of the cell phones I’ve had in the past have made computer speakers and baby monitor recievers emit a loud distinctive buzzing sound when I am about to recieve a SMS or call, or just to tell the cell tower “here I am”. I should add that even if the speaker is turned down low, the buzz is very loud. And all of the speakers I am referring to have a volume knob and amplifier directly attached to the speaker. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [August 19, 2010, 5:47pm UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/33 "2010-08-19T17:47:09Z")
> [@Gagundathar](#): > > From what I understand, active cell phones are not actually a safety hazard onboard an airplane. Not quite true. Cell phones can interfere with navigation and communication equipment. In addition to the aforementioned Mythbusters tests, I have also spoken to actual pilots to try and get an idea of just how much of a problem it really is. The only planes where they reported seeing problems with navigation instruments are the old small planes (those little Piper Cubs and the like), and then it was more of an annoyance than an actual problem. As one pilot said, “we’re not stupid.” If the compass immediately spins around and says you are heading west instead of north and you didn’t turn, the pilot knows it’s just the compass going wonky and can rely on other methods of navigation. The pilots of big jets (of which I admittedly only talked to two of them) said that they had never seen cell phones interfere with navigation equipment. They all complained about noise in their headsets which made it sometimes difficult to hear the communication from the aircraft controller they were trying to talk to. So, it’s not like the plane is suddenly going to drop out of the sky, but I personally would call distracting the pilot or interfering with his ability to speak to the controller a bit of a safety issue. > [@Gagundathar](#): > > The problem is that when the aircraft is below about 10,000 feet, the cell phone towers are in contact with the active cell phones. The software in the tower is designed to handle transmit speeds that are consistent with highway speeds, not aircraft speeds. So, there is a potential for the tower’s operation to be compromised by the speedy cell phone when the signal is handed off to another tower. The problem wasn’t so much that the handoffs occur at speeds the towers weren’t expecting, or that the cell phone was contacting multiple towers, which was also mentioned in this thread (though that was sometimes a problem). The real problem was that the cell phones were simultaneously contacting multiple cell phone systems, and the handoff between systems wasn’t designed to handle it. This caused some major problems and even shut down a few cell phone systems. Unfortunately, it seems that the best way to guarantee that someone will use a cell phone in a particular area is to tell cell phone users that they can’t use their cell phones there. So, the cell phone companies just had to cope. They did a lot of software patches so that their systems wouldn’t go all wonky whenever some yutz with his cell phone on flew overhead. This hasn’t been a problem for many years now. There is still the issue that airborne cell phones will tie up communication channels in multiple towers, which reduces the bandwidth available to other folks, which is one of the reasons the FCC still bans them on aircraft. > [@Rhodes](#): > > Some cell phones periodically cause interference on some speakers. Amplified speakers are more likely to be affected than passive speakers, just because the amplifier in the speakers will amplify the noise. Certain types of phones are more likely to cause interference than others just because of the way they communicate. Some put more of their energy on single frequencies instead of spreading out the energy. Different phones may cause different types of interference to different types of speakers as well. The exact design of the speakers (the wire lengths and orientation of the wires and circuit traces, etc) will make them more vulnerable to interference on some frequencies more than others. ---
**Author:** ![Oakminster](https://avatars.discourse-cdn.com/v4/letter/o/77aa72/32.png) [@Oakminster](https://boards.straightdope.com/u/Oakminster)\ **Post date:** [August 19, 2010, 5:55pm UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/34 "2010-08-19T17:55:56Z")
> [@Gray\_Ghost](#): > > It could be worse. This may be apocryphal, but I remember attorneys talking about a judge in N.D. Texas who demanded that the batteries be removed from all cell phones, pagers, etc… in his courtroom. If a cell phone went off anyway, it was an instant contempt of court finding, with a typical fine being $500, payable on the spot. > > Not sure if it was true, or only happened to one person, but the essential message, “Don’t mess with a Federal Judge in their court,” was pretty clear. LOL. I happened to have a rare hearing in Federal Court on September 12, 2001. Unbeknownst to me, that Judge barred cell phones from the entire building. This courthouse is downtown in a much larger city than the place I live now, and I’d parked several blocks away. The marshalls would not let me in the building with the phone. The marshalls would not hold the phone while I did the court thing. Fortunately, I had a little time to play with, but not much. Emergency call to the office, scrambled a secretary to drive downtown to take custody of the phone. Clock ticking. Somebody suggested I just hide the phone near the courthouse. Go back an look at the date of my hearing again. No way in hell I was going to be seen burying/hiding any damn thing near a federal building on that date. Strongly suspect a sniper on the roof woulda dropped me in dramatic fashion. Finally, the secretary pulls up…it’s a one way street, stopping is…not good there. She slows down, I throw the phone in her window, turn and sprint to the building, marshalls watching and laughing the whole time. Made the hearing. Barely. Now I avoid federal court if at all possible. ---
**Author:** ![leftfield6](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leftfield6/32/18780_2.png) [@leftfield6](https://boards.straightdope.com/u/leftfield6)\ **Post date:** [August 19, 2010, 6:41pm UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/35 "2010-08-19T18:41:01Z")
> [@Oakminster](#): > > Now I avoid federal court if at all possible. I find this to be good advice in general. 🙂 ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [August 20, 2010, 7:15am UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/36 "2010-08-20T07:15:26Z")
> [@Xema](#): > > One plausible explanation that’s occasionally put forward says that airlines don’t want you distracted by a phone conversation during flight - you might not pay attention to the safety briefing, or be alert for instructions in case a problem happened. An even more plausible explanation is that airlines would rather you use the phones installed on the backs of seats, because they get a cut of the high charges for those. ---
**Author:** ![KinkiNipponTourist](https://avatars.discourse-cdn.com/v4/letter/k/e9bcb4/32.png) [@KinkiNipponTourist](https://boards.straightdope.com/u/KinkiNipponTourist)\ **Post date:** [August 20, 2010, 8:57am UTC](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658/37 "2010-08-20T08:57:07Z")
[quote=“Gary “Wombat” Robson, post:29, topic:550658”] > [@KinkiNipponTourist](#): > > I use wireless interpreting equipment (Panasonic’s Panaguide system) and get horrible interference from cell phones. I wonder what the difference is? Court reporting systems consist of a computer system, specialized software, and a stenotype keyboard (possibly wireless). Interpreting equipment (voicewriting, audio recording, video recording…) is a whole different animal. [/QUOTE] The system I use has no voicewriting or any kind of recording abilities at all. It’s just a wireless transmitter and multiple receivers, using 2 channels. Thank you for clarifying what court reporting systems consist of. [Previous page](https://boards.straightdope.com/t/if-a-court-room-can-tell-if-my-cell-phone-is-on-why-cant-an-airplane/550658.md?page=1)