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#11
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I dunno guys.
It's not uncommon for a phone operated on the ground to be in reach of several cells. A server arbitrates which of the available cells your call should go through. I've also heard that it is difficult to get a signal if you're very high because the antennae on the towers are optimized for catching signals originating on the ground -- I've also heard stories disputing this, included the 9-11 stories. Bottom line--it's illegal and distracting so you shouldn't do it. Why it's illegal in the US, I don't have a clue. wrote in message oups.com... You ever drive behind someone on a cell phone call? ;-) Stand back.. there will be others... here they come.... The technical issue is if you hit multiple cells at one time you may have your account shut donw for a bit, looks like the cell was cloned to them. And it may be illegal in your country. |
#12
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Interesting article in this respect for the US based pilots at
http://www.macnewsworld.com/story/39038.html. Generally the reception of GSM signals a dew degrees above the horizontal is very poor. In the UK the signal drops in and out repeatedly and a lot of the time a phone is non usable. The generally accepted reason for this was that a phone would connect to multiple cells and cause problems on the ground ( I doubt it since the system was designed around mobile handsets anyway but I stand to be corrected by an authoritative source ie: a systems engineer currently working for a cellphone company! ) Ian Roger Worden wrote: I've seen a couple of references to someone not wanting us to use cell phones while gliding. I haven't seen the reason... what's the rationale? |
#13
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Hi,
on the antenna front I can make some comments. The length of an antenna changes its radiation pattern. In simple terms the 1/4 wave that most of us use has a high angle of radiation, but presents a 50 ohm impedance to the radio (for which most of them are tuned) It you go to a 1/2 wave (or even 5/8ths or 3/4 wave) you have a lower angle of radiation and can effectively transmit further over the ground. The only problem then is that you no longer have 50 ohm impedance so need a "matching" network. So the antennas used on mobile networks may well be low radiation types which would find it difficult to "see" you at height. I certainly have tried this out in the air at my club in the UK and much over 2000 feet do not get a signal. Malcolm... -.- "For Example John Smith" wrote in message ... I dunno guys. It's not uncommon for a phone operated on the ground to be in reach of several cells. A server arbitrates which of the available cells your call should go through. I've also heard that it is difficult to get a signal if you're very high because the antennae on the towers are optimized for catching signals originating on the ground -- I've also heard stories disputing this, included the 9-11 stories. Bottom line--it's illegal and distracting so you shouldn't do it. Why it's illegal in the US, I don't have a clue. wrote in message oups.com... You ever drive behind someone on a cell phone call? ;-) Stand back.. there will be others... here they come.... The technical issue is if you hit multiple cells at one time you may have your account shut donw for a bit, looks like the cell was cloned to them. And it may be illegal in your country. |
#14
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Earlier, Roger Worden wrote:
I've seen a couple of references to someone not wanting us to use cell phones while gliding. I haven't seen the reason... what's the rationale? Umm, because it's illegal? Here in the US at least. Here's a link and quote from the Web site of the US Federal Communications Commission: http://ftp.fcc.gov/cgb/consumerfacts/cellonplanes.html : Currently, cell phone users generally are permitted to use : their phones before takeoff and after landing. FCC rules : currently ban cell phone use after a plane has taken off : because of potential interference to cellular phone : networks on the ground. In addition, the Federal Aviation : Administration (FAA) has rules prohibiting in-flight cell : phone use because of potential interference to navigation : and aircraft systems. Thanks, and best regards to all Bob K. http://www.hpaircraft.com/hp-24 |
#15
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Roger Worden wrote:
I've seen a couple of references to someone not wanting us to use cell phones while gliding. I haven't seen the reason... what's the rationale? The most common answer seems to be that the handset would "talk" to too many base stations simultaneously. This is incorrect, as the GSM protocol will not allow that. I'm sure the CDMA protocol in the US does the same. However, as the handset moves, the network has to coordinate handovers between cells, which increases network overhead. Most aircraft are faster than cars, so they cause more handovers. I'm sure the rule applies to gliders and baloons simply because nobody bothered to make a distinction. Kind regards, Iwo |
#16
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That was very useful. I knew about the IFR and carrier restrictions
in the FAA regs against cell use (and I think it even covers taxiing) but I didn't know the FCC stuff. Thanks! In article . com, rromanATfrontiernetDOTnet wrote: Roger Worden wrote: I've seen a couple of references to someone not wanting us to use cell phones while gliding. I haven't seen the reason... what's the rationale? In the US there are FCC regulations prohibiting the use any aircraft - from a FCC web page: Section 22.925 of the Commission's rules, 47 CFR Part 22, provides that cellular telephones installed in, or carried aboard airplanes, balloons, or any other type of aircraft, must not be operated while the aircraft is off the ground. The FCC concern is interference they may cause. -- ------------+ Mark J. Boyd |
#17
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Iwo Mergler wrote:
Roger Worden wrote: I've seen a couple of references to someone not wanting us to use cell phones while gliding. I haven't seen the reason... what's the rationale? The most common answer seems to be that the handset would "talk" to too many base stations simultaneously. This is incorrect, as the GSM protocol will not allow that. I'm sure the CDMA protocol in the US does the same. However, as the handset moves, the network has to coordinate handovers between cells, which increases network overhead. Most aircraft are faster than cars, so they cause more handovers. I'm sure the rule applies to gliders and baloons simply because nobody bothered to make a distinction. I suspect that is right. Apparently, the RAS community doesn't include any cellular system engineers, or perhaps they have to take an oath of secrecy. This question comes up amongst airplane people, too, and I've never seen a reply anywhere from someone that actually is trained and knowledgeable about the systems. There certainly are a lot people high in the air making calls, like pilots, hikers, and mountain climbers, but I've not heard of anybody being chased down and fined. I do know my cell phone company has never mentioned the subject in all the literature they send me, so I'm guessing it's not a problem for them. I think the biggest issue for glider pilots is the distraction of using the phone. -- Change "netto" to "net" to email me directly Eric Greenwell Washington State USA |
#18
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I heard recently on NPR the FAA is conducting studies on commercial aircraft with cell phones and approval may come in a couple of years. Clearly a good news bad news for those of us with frequent biz-travel (an enforced respite from the phone is nice and who hasn't had enough of overhearing someone yelling "can you hear me now"). If people fly gliders as poorly as they drive cars speaking on a cell phone, that would be a bad thing. We have enough going on in the cock pit without an additional distraction. Chip F. |
#19
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I wouldn't worry too much about lighting up cells. Your digital phone
has a pretty weak transmitter and your glider does a pretty good job of attenuating signal in every direction that cannot see, especially if its carbon. If you have a good reason to make a call and can do it safely, why not. I've called 911 several times. And the retrieve office on several occasions when I couldn't get a response by radio. Legalities... well, laws are made for lots of reasons. The important ones are enforced. |
#20
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In article ,
Eric Greenwell wrote: Apparently, the RAS community doesn't include any cellular system engineers, or perhaps they have to take an oath of secrecy. This question comes up amongst airplane people, too, and I've never seen a reply anywhere from someone that actually is trained and knowledgeable about the systems. I wouldn't call myself a "cellular system engineer" but I've written code that runs in the controlling computers for cell phone systems (both GSM and CDMA), and I've spent time driving around measuring signal strengths and data rates and diagnosing localized problems with those things and with handoffs from one cell site to another. In the CDMA system as used in the USA and by Telecom here in NZ), the phone maintains up to three site in the "active set", plus half a dozen more in the "candidate set". One of the sites in the active set is the current pilot, which is the one that data is actually being sent through. The phone has dedicated hardware (called a "finger") to monitor and talk to each of the three active set members, and a single extra set of hardware to scan the candidate set in turn, and decide whethe to move one of them into the active set (replacing another one). The phone will handoff to one of the other sites in the active set if that signal gets enough better than the current pilot for long enough. Each cell site has a set of up to twenty "neighbours" programmed into it by the phone company. A new site can not get into the candidate set unless it is a neighbour of one of the sites in the active set. Thus sites too far away can not tie up resources in the phone or the network (although if they have a strong signal they can appear as "noise" and make it harder to talk to nearby but weak sites). There are several other mechanisms to prevent far-off sites from talking to a phone. One is the "search window". Typically cell sites in a city are set up to reject communication attempts from phones that are more than, say, 20 "chips" (about 5 km) away. Also the antennas themselves will often have downtilt (either mechanical or electronic or both) applied so that the main beam can't be picked up from too far away. All the above applies to the newer digital systems (CDMA, though GSM is similar) which should not be troubled at all by a few people in slow-moving gliders. The older analogue systems were far less sophisticated and could be much more easily swamped. Phones travelling at 1000 km/h would do interesting things as there is usually, for example, around a three second delay before handing off to a cell site with a better signal. -- Bruce | 41.1670S | \ spoken | -+- Hoult | 174.8263E | /\ here. | ----------O---------- |
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