tachyon_1@email.com wrote: > The other problem that jumped out at me was the idea that the people on > flight 93 used their cell phones to call family members. This just will > not work, I can unequivocally state that cell phones work just fine from an airliner. I can't say how I know this, since the person doing it was violating both FCC and FAA rules at the time of the "demonstration". But, you seem enamored with physics, so go do the RF math. The free-space path losses aren't that high, and depending on carrier type and modulation type, the phone will capture the receivers at multiple cell sites (the real reason they don't want you doing it - it wastes a ton of spectrum because cellular systems are RF-designed for ground-level line-of-sight) from even a modestly high altitude. You can calculate the losses at 800 MHz, 900 MHz, and in the low 1.0 GHz ranges for the skin of the aircraft, minus the openings for windows, etc... yes, it can be modeled. Go do your homework. You can do all the math for an analog signal, but getting certain entities to share some of their secrets in how they handle base station to base station handoffs and at what BER/RSSI levels when using digital modulation types might be a bit more problematic. The modulation types are standards, but how each base station handles them is a trade-secret, probably not held too tightly because of the need for *some* interoperability... so you can probably find some information on it. Then you need to research how TDMA, iDen, CDMA, and GSM all do handoffs and signal strength calculations, and get back to us. Until then, your opinion (which today is just Bravo Sierra, based on almost no RF facts) -- might hold some water then. Generically, at certain altitudes, you're going to stay on the same tower for the vast majority of the conversation anyway, because it's line of sight. The system isn't going to switch you until your BER or RSSI drops below a certain point. When 20 towers can hear your phone perfectly, there's no need to switch you. (Actually 20 towers might be too many -- some networks do have lockouts for phones that are hitting too many sites... because the system assumes the phone is airborne. All networks are different. Please feel free to study them all and write to all of the manufacturers of base station equipment.) > In fact it's only in recent weeks that the first airline (Dubai > airlines) deployed planes with the required on-board repeaters and ground > links to allow cell phones to work on board a moving aircraft. This has > been proven in actual tests as well. Cell phones have a 0.4% rate of even > connecting with a tower long enough to even initiate a call, never mind > hold a conversation. Site your references. Are you talking about low altitude, high altitude, over the friggin Atlantic? From my experiences in both light aircraft and larger aircraft, this claim is 100% bogus when lower than 20,000' MSL over rural terrain where the towers are spread out and frequency congestion is low. > When faced with this fact many people cry "obviously > they were using the in flight aircraft phones, not their cell phones" > however this is patently false. It was widely reported and verified from > phone records and families that the calls were made from cell phones. > That and these phones can be shut off from the cockpit which the > terrorists would surely do. As for turning off the flight phones -- if you listen to the tapes and watch the ground tracks of the various aircraft from their FDR's, you will see the hijackers had their hands full just maintaining aircraft controllability. A few hours in a C-172 doesn't prepare you for the flight dynamics of a lightly loaded 767 or in the power mangement skills required to fly a turbine-powered aircraft. You can fly it, but you'll suck at it. They did. They were busy. Too busy to screw around with breakers on a sub-panel. The autopilot was off a lot (which is a very bad way to fly a modern airliner -- your workload increases dramatically and your scan rate has to stay fixed on the flight instruments). They *did* manage to turn off the transponder -- that's an obvious one -- and only by accident or dumb luck did the transponder come back on in UAL 93 later in the flight. Their original plan would have put all three aircraft in the air at the same time, meaning that cutting off passenger communication with the ground simply wouldn't be a priority. It would have all been over before anyone thought to make a phone call if 93 hadn't been delayed outbound that morning, on the ramp. In fact the EWR tower closed the field only a couple of minutes after 93 departed... after watching the other two aircraft hit. Unfortunately, too late. There also was no focus in any of their training backgrounds to give them the type of systems training that airline pilots go through, memorizing every system, every switch location, and every possible interaction between those systems. They probably couldn't have located the breaker for the GTE/AIRINC phones on the various breaker panels if they tried. Even better, it's likely that American and United don't place this breaker in the same place in their cockpits. Never investigated that part myself, but each airline custom-orders their cockpit layout from the manufacturer, and different options mean different panel locations. Accessories like airphone service are add-ons that can literally be put just about anywhere on a sub-panel... > It's telling to me that no news agency has > followed up on tracking which towers these calls were actually initiated > from. That and the Cleveland Airport reports of 93 landing there. The > implications of the flight 93 inconsistencies are enormous and > frightening. I don't know what to think about it all as I'm not willing > to accept the enormity of what this evidence would imply. But I DO think > that people need to do their own research, demand answers from their > government, and push news agencies to do some real investigative > reporting. To quote the X-Files, "The truth is out there". Or perhaps they DID do the research and found (gasp...) no NEWS? Yeah. Sure. Couldn't possibly be that they pulled the reporter after looking into it, and aired something more interesting to keep their viewers? The mixup about 93 landing at Cleveland is an easy one. Cleveland Center handled 93's overflight and turn-around back toward the East. Cleveland probably reported that 93 had landed because they confused 93 with another aircraft in the largest shutdown of airspace ever done since Orville and Wilbur first flew. The controller who handled the 93 at Cleveland ARTCC heard the pilots beat to death in his headset, as he wished he could do something for them. One of them had the foresight to mash down on the PTT switch on the yoke while they struggled and died, to warn others that their aircraft had been taken. That controller now won't give interviews and has left ATC work. Think you could handle it better? Finally -- at least one passenger on board UAL 93 *was* using an AIRINC phone, as the GTE operator who talked to him for over an hour attests. People grabbed whatever they could. Some cells worked, many calls were on the AIRINC/GTE system. Nate -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist