White Raven,
No one is perfect. We are all learning. I apologize if I sound like I think I know it all. I also apologize for not taking the time to write a complete explanation of why I believe what I do.
I will plead guilty to some over simplifications. So let me address each of your points…
Too bad you don't understand antennas as they are used in the cell sites. If you did, you would not have posted this. Resistance is uninformed....
Actually I have a pretty good basic understanding of the principles of antenna’s though I will admit that I am not an electronics engineer. This much I do know, and that is that there are two general kinds of cell phone tower antennas; directional, like the ones you speak of, that essentially point in a single direction and omnidirectional that point 360 degrees on the horizontal and varying numbers of degrees on the vertical.
I also know that the omnidirectional antennas are used by cell phone companies in mountainous regions in order to connect between varying altitudes of mountaintop-to-mountaintop receivers. I also know that the Allegheny and Blue Ridge mountains lie just west and north of the whole eastern seaboard area. So we cannot rule out the possibility that these cell phone towers could pick up the cell calls in question.
Wrong again. Sprint in many of its coverage areas goes directly from the cell tower to land line. Only out in the boonies is it MICROWAVED to another cell site and then to a land line. I worked for Sprint twice. The second time was with the group putting up cell phone sites in Orange County, California. I KNOW what I am talking about. Resistance is STILL uninformed....
I will defer to your greater expertise when it comes to Sprint, since you have worked for them and I have not. However, I will point out that Sprint, MCI, Cingular, Qualcomm, in short virtually all cellular providers utilize all the communications infrastructure available to them, which include networks of cell towers, landline, and satellite communications as well.
All of these are linked in a complex network of switching stations that I won’t pretend to be able to fully explain, but do know it exists, otherwise all the PCS/Personal Communications services such as cellular e-mail/video phone/GPS/etc would not work from your little hand set.
Wrong again. Line of sight is line of sight - period. Coverage of cell sites has to do with line of site to the DIRECTIONAL antenna. Obstructions to line of site cause problems for the RF engineers. (An example is the size of the leaves on a Eucalyptus tree is close to the wave length that Sprint was using and the trees in a park they were trying to cover was just dead zone.) The ANTENNAS at a cell site are ALL directional - that is why you see several of them to give 360 degree coverage. And they are pointed OUT not UP!!! The DIRECTIONAL antennas cannot see the airplane ABOVE them. Yes, the cell phone in the airplane can look down and see the cell site, but the CELL SITE is NOT looking UP to see the airplane. Resistance is not informed on this either!!!
The following picture shows a cellular repeater area map of the eastern United States in the area of Washington D.C. and Virginia.
In the urban areas it is clear that the directional antennas are used as the clustering of cells is so thick and the line of site so uniform that they do not need omni-directional antennas. These are the antennas in red triangles. The red triangles with a green stripe are cellular towers that utilize omni-directional antennas because they are located in mountainous regions. These kinds of antennas look up, down and sidewise as well as from one cell tower to another.
As you can see there are omni-directional cellular towers that look down into the metropolitan areas from all along the Blue Ridge Mountains in this area.
Since you think that a cell site has a 25 mile radius, how did you arrive at the 3.25 minutes number? Your math makes no sense at all. At 500 mph, 25 miles would be covered in 3 minutes. However, since the cell site doesn't see the plane, it wouldn't matter at all. Yes, there is a "handshake" involved. But it doesn't work like you say - and besides, all of those cell sites would be "seeing" the plane IF they were looking UP (which they aren't) so which cell site would the plane be talking to??? All cell sites in line of sight of the plane would be trying to handshake. Resistance is totally illogical!!!! IF things worked like you say, then ALL of the cell sites that could be seen from the airplane at 35,000 feet would be trying to handshake with the cell phone in the plane. Now do you REALLY think that is what went on???
I stand corrected on the diameter of a cell. This is actually 25 kilometers, which is roughly 16 miles. I, like many Americans think more naturally in avodupois than metric. At 500 miles per hour an airplane travels 500/60 = miles per minute. That divided into the number of miles across the cell gives the time it takes to travel across the cell. Since I admit I was wrong about the diameter of the cell I revise that time to be 500/60 = 8.33 miles per minute. 16/8.33 = 1.920 minutes to cross the cell.
Since the handshake takes about 20 – 45 seconds, and then the signal can be handed from cell to cell as it moves then it still is possible for the tower to acquire a signal and then hand it on to the next cell as the signal moves towards it. Another part of this argument that has some question to it is the 35,000 foot altitude being used to establish the baseline here.
Although the cruising altitude is indeed 35,000 feet, most of these calls were made, supposedly after the aircraft had been hijacked and were now en route to their targets. Only a comparison of the radar signatures of these aircraft in relationship to the timing of the calls would actually tell us at what altitude those calls were made. Since the hijackers turned off their transponders we are left with only speculation as to what altitude they were at when these calls were made.
So that you know I am not talking without any experience I did take a few hours of flight training when I was younger. I know that the hijackers will have tried to lower their altitude, at least some distance from their targets in order to be traveling at the right altitude to make their final adjustments fairly quickly. Secondarily they could well have slowed their airspeed in order to bleed off altitude, which would have correspondingly increased their time in any given cell. I am not saying these things did happen, I am only saying that they are information that has to be considered before one can state, without equivocation that the “…cell phone calls from the hijacked airliners were impossible…”
This has nothing to do with anything we were talking about above. The satellites in geosynchronous orbit are not operating on the cell phone frequencies. Look at the band plan - you can probably find it at the FCC website. Or ask knowledgable ham radio operators who have their own sats to play with....
Actually, this does have to do with one of the points being made and that was that low power transmission limits the range of cell phones. However, when line of site is not an issue, then low power transmission does not limit the cell phone range nearly as much. I was not making a point that cell phones transmit to satellites, only that their transmitters are strong enough to cover a great deal more distance, line of site, than necessarily the distance between cells in an urban area. However, the cells transceivers are keyed to signal strength for reception and handing off a signal from one cell to another. They are kept to low power transmission, it is my understanding, in order to economize on battery size and power as well as to minimize interference across the distances of other cells.
They have solved this problem to the point of giving coverage not only in buildings but also in elevators. Sprint had this figured out several years ago....
So let’s see the actual studies to see what exactly was controlled for besides altitude. My point was not that there aren’t solutions to the problem of materials that might absorb cellular RF signals but that such materials might not have been solved on the aircraft being used in the testing in question, or controlled for on the aircraft in question on the studies that were cited in the original post.
You couldn't pass a test for a novice ham license. I know. I am an Extra class ham who has tested over 4,000 individuals from age 6 to 92. You don't know what you are talking about. I do.
I did not realize that I was studying for a novice ham license. I am not a ham operator, which is shortwave RF. Here is my experience if you must see it. I have been a practicing Emergency Medical Technician for 30 years and a Paramedic for 26 years. During that time I have worked with and assisted in the installation of, Low Band RF Simplex Systems, High Band RF Simplex Systems, HI/LO Duplex RF Systems, RTSS Systems, UHF/VHF Microwave Communications Systems, Cellular Systems, Hybrid Cellular systems, Citizens Band Systems.
I have operated radios and telecommunications systems from moving ambulances on the ground and in the air in the states of California, Oregon, Nevada, Louisiana, Mississippi, Alabama, Arkansas and Texas. I have helped to install radio and telecommunications systems in ambulances, automobiles, aircraft, hospitals and service base stations. I have helped to draft the specifications for grant applications to install several of these different kinds of systems.
I have met FCC Requirements involved in the licensure to operate all of these systems, though I will admit that I would have to study to pass a novice ham radio operator’s licensure exam. Also I will admit that I do not have any current licenses in any of these levels of operation.
White Raven I respect your posts on many subjects, and I respect your information on this one as well. What you posted is true; it is just not all of what is true. My perspective on something like this post is that I see myself as a member of a jury that is trying to deliberate the truth of the subject at hand. When I am presented with something that attaches the word “proof” to itself, then I apply the legal standard to that proof. In short I believe it must be “proved” beyond a “reasonable” doubt, not all doubt, reasonable doubt. If, either in my own knowledge, or my ability to do research I can find reasonable and alternative explanations, then I conclude that though what has been offered might well be evidence, it is not “proof” in that sense.
If my oversimplification of the complexities of radio and telecommunications seemed to be talking down to anyone, I apologize, they were not meant to seem patronizing. Personally, it took me many years to understand the basic physics of electromagnetic radiation and how it works and how antennas receive it and how information is coded and the differences between FM and AM and digital and analogue and I do not by any means claim to be expert in the subject, only to be knowledgeable enough to, as Rayelan might say, be dangerous…
Finally, this debate is very important and so it is important our facts are straight and aboveboard. We already know that it is possible to receive and make cell phone calls from aircraft, the study cited in the original post said as much when it states that there was a
89% at 2,000 feet
44% at 4,000 feet
30% at 6,000 feet
9% at 8,000 feet
So we know that at 8,000 feet one of every ten cell phones had an opportunity to get through. What we don’t know? Is it reasonable to believe that out of four hundred people on four aircraft there were enough attempts to make cell phone calls to account for 16 of those calls getting through to a cell? If we assume - and this is an assumption not advanced as a fact - 25% of those on board had cell phones and that they all tried to make cell phone calls, we can estimate that 10 of those calls would get through. If only fifty percent tried more than once then another five calls could have gotten through, which would account for roughly 15 calls. Since the number of calls accounted for by witnesses is 16 that puts the number in the right area. Still this is only speculation; but not unreasonable speculation.
Does anyone out there in reader land have additional Radio Frequency engineering information on this subject, as well as information on radar positions of the aircraft after they turned off their altitude transponders? If you have information to add to this debate, then e-mail me at the e-mail address referenced on this post.
Resistance is Feeding the Kitty
Nine of Eleven
Don't forget to feed the kitties!
http://www.rumormillnews.com/DONOR_PAGE.htm
: Don't forget to feed the kitties!
: http://www.rumormillnews.com/DONOR_PAGE.htm
: Too bad you don't understand antennas as they are used in the
: cell sites. If you did, you would not have posted this.
: Resistance is uninformed....
: Wrong again. Sprint in many of its coverage areas goes
: directly from the cell tower to land line. Only out in the
: boonies is it MICROWAVED to another cell site and then to a
: land line. I worked for Sprint twice. The second time was
: with the group putting up cell phone sites in Orange
: County, California. I KNOW what I am talking about.
: Resistance is STILL uninformed....
: Wrong again. Line of sight is line of sight - period. Coverage
: of cell sites has to do with line of site to the
: DIRECTIONAL antenna. Obstructions to line of site cause
: problems for the RF engineers. (An example is the size of
: the leaves on a Eucalyptus tree is close to the wave length
: that Sprint was using and the trees in a park they were
: trying to cover was just dead zone.) The ANTENNAS at a cell
: site are ALL directional - that is why you see several of
: them to give 360 degree coverage. And they are pointed OUT
: not UP!!! The DIRECTIONAL antennas cannot see the airplane
: ABOVE them. Yes, the cell phone in the airplane can look
: down and see the cell site, but the CELL SITE is NOT
: looking UP to see the airplane. Resistance is not informed
: on this either!!!
: Since you think that a cell site has a 25 mile radius, how did
: you arrive at the 3.25 minutes number? Your math makes no
: sense at all. At 500 mph, 25 miles would be covered in 3
: minutes. However, since the cell site doesn't see the
: plane, it wouldn't matter at all. Yes, there is a
: "handshake" involved. But it doesn't work like
: you say - and besides, all of those cell sites would be
: "seeing" the plane IF they were looking UP (which
: they aren't) so which cell site would the plane be talking
: to??? All cell sites in line of sight of the plane would be
: trying to handshake. Resistance is totally illogical!!!! IF
: things worked like you say, then ALL of the cell sites that
: could be seen from the airplane at 35,000 feet would be
: trying to handshake with the cell phone in the plane. Now
: do you REALLY think that is what went on???
: This has nothing to do with anything we were talking about
: above. The satellites in geosynchronous orbit are not
: operating on the cell phone frequencies. Look at the band
: plan - you can probably find it at the FCC website. Or ask
: knowledgable ham radio operators who have their own sats to
: play with....
: At this point, I am not going to take anything you say on this
: subject to have any basis in reality. Resistance is so out
: of touch with logic as to be worthless.
: They have solved this problem to the point of giving coverage
: not only in buildings but also in elevators. Sprint had
: this figured out several years ago....
: You couldn't pass a test for a novice ham license. I know. I
: am an Extra class ham who has tested over 4,000 individuals
: from age 6 to 92. You don't know what you are talking
: about. I do.
: WhiteRaven
: Now go feed the kitties a little more, OK?
: http://www.rumormillnews.com/DONOR_PAGE.htm
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