30 Years of the Digest ... founded August 21, 1981
The Telecom Digest for January 17, 2012
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Date: Mon, 16 Jan 2012 15:19:00 +1100 From: David Clayton <firstname.lastname@example.org> To: email@example.com. Subject: Re: Ringing Finally Ended, but There's No Button to Message-ID: <0x95NC.A.V1B.KzEFPB@telecom> On Sun, 15 Jan 2012 08:58:55 -0500, Barry Margolin wrote: .......... > I do find it a bit hard to believe that he didn't know it had an alarm: > even dumb cellphones have this, and how could he have set the alarm > without going into the app? I don't have an iPhone, but I expect that it > takes more than one errant click to set the alarm. I have some sympathy for this person, I use an Android phone and while it has various "Silent" and "Airplane" modes that seem to work for "normal" things like incoming calls I have also installed various apps to signal me on things like incoming e-mails and I am not sure that all of these use the aforementioned settings. All it may need is one lazy app developer to bypass the bits that control to alarm modes and then you have a device that can only be shut off with a hammer (or the power button....) -- Regards, David. David Clayton Melbourne, Victoria, Australia. Knowledge is a measure of how many answers you have, intelligence is a measure of how many questions you have.
Date: Mon, 16 Jan 2012 07:51:23 -0600 From: firstname.lastname@example.org (Robert Bonomi) To: email@example.com. Subject: Re: Ringing Finally Ended, but There's No Button to Message-ID: <__adnXQi0P7GtonSnZ2dnUVZ_rqdnZ2d@posted.nuvoxcommunications> In article <nDbw8.A.QtC.S2nEPB@telecom>, Monty Solomon <firstname.lastname@example.org> wrote: > >Ringing Finally Ended, but There's No Button to Stop Shame > > >***** Moderator's Note ***** > .... The gaul of some people! <nitpick> the word is 'gall', not 'gaul'. </nitpick> Unless they're of Old French background, that is. <grin>
Date: Sun, 15 Jan 2012 22:56:54 -0500 From: tlvp <mPiOsUcB.EtLlLvEp@att.net> To: email@example.com. Subject: Re: Ringing Finally Ended, but There's No Button to Message-ID: <firstname.lastname@example.org> On Sun, 15 Jan 2012 08:58:55 -0500, Barry Margolin wrote: > RTFM? Of an iPhone? No, no, not of the iPhone, silly -- of the concert hall! Every printed program, in every concert hall I've attended in this 21st century, has stated, plainly and clearly, that patrons are requested to turn their cell phones, pagers, and beepers OFF for the duration of the concert. Most concert venues add a pre-performance PA announcement to the same effect, for the benefit of those patrons who can't or won't -- or just didn't -- read. > The guy said that he switched the phone into silent mode. He may have tried, but he obviously didn't entirely succeed :-) . Cheers, -- tlvp -- Avant de repondre, jeter la poubelle, SVP.
Date: Mon, 16 Jan 2012 04:34:23 +0000 (UTC) From: email@example.com (Michael Moroney) To: firstname.lastname@example.org. Subject: Re: Lightsquared/GPS Message-ID: <email@example.com> Randall Webmail <firstname.lastname@example.org> writes: >LSQ has a license to use their frequencies and GPS devices use >adjacent unlicensed frequencies, correct? Don't unlicensed devices >(such as GPS) have to accept interference from other devices, as a >condition of their unlicensed use? >It'd really suck to have to replace all my GPS devices, as they are >quite useful, but since LSQ has a license and GPS doesn't - why is >this a question? The FCC doesn't license receivers. They license transmitters. The GPS on your dashboard is a receiver, the FCC license (if it applies at all to military devices, as Bill points out) would be for the GPS satellites. ***** Moderator's Note ***** There are broad bands of frequencies set aside for civilian and for military/government use, and the FCC does not have authority to assign licenses that use military bandwidth. When economies of scale dictate that bands be shared - soldiers need to use "commercial" walkie-talkies while on guard duty, for example - there's a coordination mechanism in place, but the FCC doesn't issue, nor are FCC licenses required for, any military transmitter. There are, of course, various exceptions, but they're unimportant. The point is that if anyone says "GPS is unlicensed", they're spreading bull manure: GPS doesn't need a license from the FCC. Bill Horne Moderator
Date: Mon, 16 Jan 2012 02:16:30 +0000 (UTC) From: email@example.com (Garrett Wollman) To: firstname.lastname@example.org. Subject: Re: Lightsquared/GPS Message-ID: <email@example.com> In article <20120115192027.GA1666@telecom.csail.mit.edu>, Bill Horne <bill@horneQRM.net> wrote: >What LightSquared has is a license for an "Ancilliary Terrestrial >Component", which is supposed to allow a company that has satellite(s) >in orbit to provide coverage in the very limited places that >satellites can't reach: tunnels under cities, etc. Not that limited. Sirius XM has more than a thousand (maybe more than two thousand) such licenses. -GAWollman -- Garrett A. Wollman | What intellectual phenomenon can be older, or more oft firstname.lastname@example.org| repeated, than the story of a large research program Opinions not shared by| that impaled itself upon a false central assumption my employers. | accepted by all practitioners? - S.J. Gould, 1993
Date: Mon, 16 Jan 2012 11:12:42 -0500 From: Bill Horne <bill@horneQRM.net> To: email@example.com. Subject: Re: Lightsquared/GPS Message-ID: <20120116161242.GA7041@telecom.csail.mit.edu> On Mon, Jan 16, 2012 at 02:16:30AM +0000, Garrett Wollman wrote: > In article <20120115192027.GA1666@telecom.csail.mit.edu>, > Bill Horne <bill@horneQRM.net> wrote: > > >What LightSquared has is a license for an "Ancilliary Terrestrial > >Component", which is supposed to allow a company that has satellite(s) > >in orbit to provide coverage in the very limited places that > >satellites can't reach: tunnels under cities, etc. > > Not that limited. Sirius XM has more than a thousand (maybe more than > two thousand) such licenses. I meant "limited" as in "a place where a receiver is unable to get signals from a satellite", not limited in number. I'm sure there are thousands of highway tunnels, and equally sure that few drivers care if their GPS can't receive while inside them: the navigation choices are, after all, somewhat limited, and the GPS unit's internal logic is adequate to quide drivers to the correct exit, even when the GPS can't "see" the satellite constellation. In any case, you bring a red herring to the dinner: Sirius operates in 2.31 to 2.36 GHz, but LightSquared wants to bull its way up next to GPS, which is at 1.575 GHz. That's a difference of about 800 MHz, and if LightSquared was trying to set up a terrestrial network 800 MHz away from GPS, we wouldn't be having this debate. Bill -- Bill Horne (Remove QRM from my email address to write to me directly) "When I was ten years old, I remember thinking how good it would be When we were going on an eight-hour drive, if we could just watch TV" - Brad Paisley
Date: Mon, 16 Jan 2012 10:28:20 -0600 From: firstname.lastname@example.org (Robert Bonomi) To: email@example.com. Subject: Re: Lightsquared/GPS Message-ID: <YLudneJVI4C5zYnSnZ2dnUVZ_vadnZ2d@posted.nuvoxcommunications> In article <528444186.671612.1326645607989.JavaMail.firstname.lastname@example.org>, Randall Webmail <email@example.com> wrote: >>Dave Murphy, PC Magazine > >> According to officials, LightSquared's proposed (and controversial) >> plan to launch a new LTE network - and then sell access rights to >> the service to regional and rural wireless carriers, and other >> partners - interferes too greatly with existing GPS systems. > >LSQ has a license to use their frequencies and GPS devices use >adjacent unlicensed frequencies, correct? Incorrect, on several counts. GPS devices are receivers. In the U.S., no receiver requires a license. The GPS satellite transmitters are "licensed" devices. By International agreement, the ITU coordinates spectrum assignments to various nations. For assignments to the United States, 'non government' use is managed by the FCC, while 'government' use (including military) is co-ordinated by the NTIA. The NTIA has assigned certain frequencies for the exclusive use of GPS satellites. That said, there is a valid element in your question. All commercial receivers (and most other pieces of 'electronic' equipment), as 'incidental' radiators of RF energy (the 'local oscillator, etc.) are required to comply with 'Part 15' of the FCC regulations, before they can be offered for sale. Part 15 limits the amount of 'unintentional' radiation that they can output, and specifies that the device must be shut down if it interferes with a licensed transmission. (note: Part 15 does not apply to licensed transmitters -- they are governed by other, stricter, rules.) There is a requirement in Part 15 that compliant devices 'accept' legal RF signals that are not part of their operation. BUT, a transmission that interferes with the 'normal operation' of a licensed transmitter (e.g., a GPS satellite) is expressly forbidden as well. You can't prohibit the lightspeed service because it generaes inteference that is picked up in a Part 15 device. You can prohibit the service because it interferes with the signal from the licensed transmitter. There is a conflict between those statements, and exactly where the line should be drawn between them is the entire controversy. Available evidence is that Lightsquared 'interferes' with the licensed GPS signal, for the vast majority of receivers deployed today. The cost of modifying or replacing all the susceptible units with one with adequate sensitivity/ selectivity to ameliorate the interference is extremely non-trivial. Adding gasoline to the fire is the fact that the Lightsquared proposal is for a materially different use of the spectrum -- with regard to transmitter locations and signal power -- than was allowed when existing GPS equipment was designed/implemented/sold. A case can be made, "in equity", that Lightsquared should bear the costs of replacing all existing equipment built that was 'adequate' for the original spectrum usage specifications, but is -not- adequate in the 'changed rules' environment that Lightsquared is requesting. > Don't unlicensed devices >(such as GPS) have to accept interference from other devices, as a >condition of their unlicensed use? Since the premise is 'false to fact' -- GPS does not involve 'unlicensed' operations -- the remainder of the question is meaningless <grin> There are FCC rules -- which apply to Lightsquared's use of transmitters on the frequencies involved -- which forbid either an unlicensed or a licensed transmitter from generating interference with other licensed operations. Unfortunately, what constitutes 'interference' is not sufficiently precisely defined in the FCC regulations, with regard to causing problems with other licensed operations. E.g. who is responsible for 'intermodulation interference' caused by the mixing of two unrelated RF signals (both from licensed transmitters0, occurring in a passive device (like the 'structural steel' of a building) and being re-radiated on the frequency of a third licensed transmitter? If either of the first two transmitters shuts down the problem 'goes away'. If the 'intermediate' radiator gets modified, the problem 'goes away'. Suppose the interference is not 'exactly' on the frequency of the third transmitter, just 'close' to it? Maybe one can, by using sufficiently 'fancy' (read as "large", "bulky", and 'expensive') filtering devices, siphon off enough of the 'interference' to be able to recover the 'licensed' signal, and maybe NOT. Taken to extremes, I wouldn't want to guess as to the cost, or size, of a GPS receiver that required a separate antenna, each with it's own 'cavity resonator' narrow-band filter for each GPS transmitter frequency. I'm fairly sure you couldn't get it all to fit in a 'hand-held' unit. >It'd really suck to have to replace all my GPS devices, as they are >quite useful, but since LSQ has a license and GPS doesn't - why is >this a question? Because the premise of your question is not in agreement with reality. :)) ***** Moderator's Note ***** Some receivers are regulated: in the U.S., it's unlawful to buy or import a "scanner" receiver capable of receiving cellular calls. Although that may not be a "license" requirement, it's a difference that makes no difference. Bill Horne Moderator
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