Re: Operations: where are you going to sit?
Subject: Re: Operations: where are you going to sit? From: Michael Shields <shields@msrl.com> Date: 07 Dec 2000 00:22:47 +0000 [...] I think this is based on the same decision process that lead to the ban on cellphones in most commercial airplanes -- some unsustantiated anecdotes, no testing, and extremely risk-averse executives. [...]
For what it is worth, I believe that the use of cellphones in airplanes is prohibited by the FCC, not by the FAA. That is, the use of cellphones in airplanes (in flight) adversely affects the cellphone system. A cellphone at a high altitude is visible in numerous cells, with conflicts with the assumption that a cellphone will be heard (more or less) only in one cell. Now, about the use of other radio receivers and transmitters in airplanes... More trivia from, -tjs
For what it is worth, I believe that the use of cellphones in airplanes is prohibited by the FCC, not by the FAA. That is, the use of cellphones in airplanes (in flight) adversely affects the cellphone system. A cellphone at a high altitude is visible in numerous cells, with conflicts with the assumption that a cellphone will be heard (more or less) only in one cell.
Now, about the use of other radio receivers and transmitters in airplanes...
And for what it's worth -- they don't work above ~3000 feet. I assume this is due to the design of the cell site antenna. Not that I ever tried it in a private plane or anything... Mark Radabaugh (419)833-3635 mark@amplex.net
On Wed, 6 Dec 2000, Mark Radabaugh wrote:
For what it is worth, I believe that the use of cellphones in airplanes is prohibited by the FCC, not by the FAA. That is, the use of cellphones in airplanes (in flight) adversely affects the cellphone system. A cellphone at a high altitude is visible in numerous cells, with conflicts with the assumption that a cellphone will be heard (more or less) only in one cell.
Now, about the use of other radio receivers and transmitters in airplanes...
And for what it's worth -- they don't work above ~3000 feet. I assume this is due to the design of the cell site antenna. Not that I ever tried it in a private plane or anything...
Mark Radabaugh (419)833-3635 mark@amplex.net
They work very well above 3000ft as long as you and the cell site that sees you are in agreement. This brings to mind something from WAY back. When I got out of the Marine Corps, I flew home to VA. When we hit pattern elevation, I used my ICOM 2M geer (previously cleared with the Airline) to bring up the auto-patch and telephone my parents to tell them I was en-route to VA. My HT was using a whopping 500mw of power. Granted, I was probably being heard (on my TX freq) US wide, but, I happened to know a "control" freq that also was used as an input freq to the WB4SQC (149.29MHz) repeater in Johnson City, TN and as such, I wasn't worried about causing problems. --- John Fraizer EnterZone, Inc
On Wed, 6 Dec 2000, Timothy J Salo wrote:
Subject: Re: Operations: where are you going to sit? From: Michael Shields <shields@msrl.com> Date: 07 Dec 2000 00:22:47 +0000 [...] I think this is based on the same decision process that lead to the ban on cellphones in most commercial airplanes -- some unsustantiated anecdotes, no testing, and extremely risk-averse executives. [...]
For what it is worth, I believe that the use of cellphones in airplanes is prohibited by the FCC, not by the FAA. That is, the use of cellphones in airplanes (in flight) adversely affects the cellphone system. A cellphone at a high altitude is visible in numerous cells, with conflicts with the assumption that a cellphone will be heard (more or less) only in one cell.
Now, about the use of other radio receivers and transmitters in airplanes...
More trivia from,
-tjs
OK folks. Lets get things straight. Cellular (IE analog and digital mobile phones) should, in normal instances, be seen by more than one cell site. In practice, each cell site has a signaling receiver which reports to the MTSO (Mobile Telephone Switching Office) the relative strength in which it is receiving a particular mobile telephone. This is what "hand-offs" are calculated from. If a phone is seen by 5 cell-sites but the site servicing that phone is saying "Help! I'm losing him!", the MTSO initates a transfer to the cell site which has reported that phone with the highest signal strength. Cellular telephony, while magic to some folks, should be simple to those of us who work in the IP routing world. It's "Hot Potato" routing. Just substitute "signal strength" seen by a cell site for "local pref" or "IGP vs EGP" on a router. It's that simple. Back in the olden days, I helped design cellular networks and I never could understand why people couldn't grasp the above concept. Now at least, I have something to compare it to. As for mobilephones at altitude, the phone itself is much more likely to have problems than the cell sites. The cell site will put a "channel" OOS (Out of Serivice) if the scanning receiver for that cell site detects a carrier on one of the "channels" that it uses and there isn't a "Valid" call on being serviced by that site. Anyone who wants further explaination of this concept, my billable rate is currently $280.00 per hour. (Just ask Alltel - They pay this.) --- John Fraizer EnterZone, Inc
participants (3)
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John Fraizer -
Mark Radabaugh -
Timothy J Salo