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Message Digest 
Volume 28 : Issue 124 : "text" Format

Messages in this Issue:
  Re: Waveguide (was "size a major consideration...") 
  Re: Nebraska commission loses appeal on Internet call fees     
  Re: Nebraska commission loses appeal on Internet call fees   
  Re: Waveguide (was "size a major consideration...")  
  Re: Waveguide (was "size a major consideration...")  
  Re: Waveguide (was "size a major consideration...") 
  Re: FiOS in MDU Buildings 
  Re: AT&T doubling 3G capacity 
  Re: Waveguide (was "size a major consideration...") 


====== 27 years of TELECOM Digest -- Founded August 21, 1981 ====== Telecom and VOIP (Voice over Internet Protocol) Digest for the Internet. All contents here are copyrighted by Patrick Townson and the individual writers/correspondents. Articles may be used in other journals or newsgroups, provided the writer's name and the Digest are included in the fair use quote. By using -any name or email address- included herein for -any- reason other than responding to an article herein, you agree to pay a hundred dollars to the recipients of the email. =========================== Addresses herein are not to be added to any mailing list, nor to be sold or given away without explicit written consent. Chain letters, viruses, porn, spam, and miscellaneous junk are definitely unwelcome. We must fight spam for the same reason we fight crime: not because we are naive enough to believe that we will ever stamp it out, but because we do not want the kind of world that results when no one stands against crime. Geoffrey Welsh =========================== See the bottom of this issue for subscription and archive details and the name of our lawyer, and other stuff of interest. ---------------------------------------------------------------------- Date: Mon, 4 May 2009 17:43:12 -0400 (EDT) From: Dan Lanciani <ddl@danlan.com> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Waveguide (was "size a major consideration...") Message-ID: <200905042143.RAA00174@ss10.danlan.com> |***** Moderator's Note ***** | |Given the cost of Heliax, and the losses of generic coax at 70cm, is |it possible/advisable to homebrew waveguide? A previous post mentioned |circular waveguide, and I wonder if I could feed 70cm or 23cm antennas |with waveguide made from copper pipe. What problem are you trying to solve? If it is feed line loss in amateur applications then (IMHO of course) the best bang for the buck would be achieved by moving the front end (receive) and final output stage(s) (transmit) to the antenna. I've often thought about a little solar/battery powered tower-mount broad-band receiver with a few selectable IF sections coupled to an A/D driving a fiber downlink. Single-band tower-mount amplifiers would be much easier, though... Dan Lanciani ddl@danlan.*com ***** Moderator's Note ***** Not an option for me: I wear a brace on my leg and I can't be climbing towers anymore. Anything that I put up has to be passive, since I can't get up there to maintain electronics. Bill Horne Temporary Moderator ------------------------------ Date: Mon, 04 May 2009 17:51:05 -0600 From: Robert Neville <dont@bother.com> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Nebraska commission loses appeal on Internet call fees Message-ID: <rnvuv4hbms6q6g3l6kjdavfg60au6ds63g@4ax.com> "harold@hallikainen.com" <harold@hallikainen.com> wrote: >This "telecommunications service" versus "information service" is very >strange. Yep. It's an artifical constraint designed to preseve the revenue being generated by the various mandated fees/taxes on POTS service. The reality is that bits are bits, being voice/date/video, and that if there are socially necessary functions that need to be funded, they should be funded out of general tax revenues. ***** Moderator's Note ***** Ah, but where's the fun in that? If you're going to rob a man, at least have the brains to do it a penny at a time! By the way, bits are no longer bits: bits that traverse a path in 3 milliseconds are different than those which take 3000. Bill Horne Temporary Moderator ------------------------------ Date: Mon, 4 May 2009 18:53:40 -0700 (PDT) From: hancock4@bbs.cpcn.com To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Nebraska commission loses appeal on Internet call fees Message-ID: <9554e368-981b-457c-8f72-b2fa0c18fbe2@o30g2000vbc.googlegroups.com> On May 3, 5:47 pm, Robert Neville <d...@bother.com> wrote: > A point of clarification here: this ruling pertains to a state that > was attempting to force Vonage to fund a state USF. This is on top > of, but separate from the Federal USF. Vonage is still required to > fund the Federal USF, as well as Federal Relay and local 911 > centers. What's really ironic is that under the old system none of this was an issue or necessary. Rates were intentionally set so that (1) the bare bottom users could get very cheap phone service and (2) emergency calls were partially paid for by the phone company through its dial zero operators. In an emergency, a dial zero operator would stay on the line as needed. In very small towns, the operator was the 911 call center. Today we have a bureacracy to qualify low-income people for specially priced phone service (which is still bare bones), when in the past there was nothing to do. You wanted bare bones a la carte service, you got it. You wanted flat rate service or premium equipment, you'd paid more for it. None of this "FCC Line Charge" or "PIC charges", etc. One problem today is that established land line carriers are required to eat a lot of bad debts by their states, something that newcomer carriers don't have to worry about. For a TRUE competitive environment, eliminate all the special burdens on traditional carriers, OR, require newcomer carriers to offer bargain service, take on bad debt, etc. ------------------------------ Date: Mon, 04 May 2009 23:57:23 GMT From: Howard Eisenhauer <howarde@REMOVECAPShfx.eastlink.ca> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Waveguide (was "size a major consideration...") Message-ID: <lkvuv4dacm1n721evjsl2n2qijrbb46223@4ax.com> On Sun, 3 May 2009 20:34:03 -0400 (EDT), T <kd1s.nospam@cox.nospam.net> wrote: >In article <jdepv45644ebu932478ko767gs1f376mue@4ax.com>, >howarde@REMOVECAPShfx.eastlink.ca says... >> >> On Sat, 2 May 2009 09:49:39 -0400 (EDT), Neal McLain >> <nmclain@annsgarden.com> wrote: >> >> >Temporary moderator wrote: >> > >> >> I'm surprised at the difference in loss of waveguide vs. coax: >> >> all the cell sites I've ever seen appear to use coax, so either >> >> they're using the flexible type [of waveguide] or the cellular >> >> engineers are employing the coax loss to contribute a large part >> >> of their loss budget for the antenna arrays being used. >> > >> >> It does indeed contribute a lot of loss, typically 3db. Wave guide >> would be alot more efficient but for the frequencies used for cellular >> (850-900 Mhz), or even the PCS bands (~2000 MHz) it would be >> impractical due to size. > >[Moderator snip] > > I've dealt with hardline for amateur radio repeaters. Tough to work > with but fairly low loss on 70cm. Everything is relative, compared to Radio Shack RG58 it certainly is low loss :). Not all hardline is created equal, the 3dB I spec'ed is a typical "aim point' for the cellular industry, when you get to the point feedline losses exceed 3dB then you up to the next larger size line, with a correspondingly lower loss. If you can get by with a smaller line (less $$$) & not exceed the 3 db loss figure then you go with the smaller line. If you've maxed out on size then you move up to an air-dielectric cable which is even lower loss than the typical foam core cable. H. ***** Moderator's Note ***** Compared to Radio Shack RG-58, Dixie cups and string are low loss! Bill Horne Temporary Moderator ------------------------------ Date: Tue, 5 May 2009 12:47:37 -0400 From: T <kd1s.nospam@cox.nospam.net> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Waveguide (was "size a major consideration...") Message-ID: <MPG.246a37b2b4848a79899fe@reader.motzarella.org> In article <lkvuv4dacm1n721evjsl2n2qijrbb46223@4ax.com>, howarde@REMOVECAPShfx.eastlink.ca says... > > On Sun, 3 May 2009 20:34:03 -0400 (EDT), T > <kd1s.nospam@cox.nospam.net> wrote: > > >In article <jdepv45644ebu932478ko767gs1f376mue@4ax.com>, > >howarde@REMOVECAPShfx.eastlink.ca says... > >> > >> On Sat, 2 May 2009 09:49:39 -0400 (EDT), Neal McLain > >> <nmclain@annsgarden.com> wrote: > >> > >> >Temporary moderator wrote: > >> > > >> >> I'm surprised at the difference in loss of waveguide vs. coax: > >> >> all the cell sites I've ever seen appear to use coax, so either > >> >> they're using the flexible type [of waveguide] or the cellular > >> >> engineers are employing the coax loss to contribute a large part > >> >> of their loss budget for the antenna arrays being used. > >> > > >> > >> It does indeed contribute a lot of loss, typically 3db. Wave guide > >> would be alot more efficient but for the frequencies used for cellular > >> (850-900 Mhz), or even the PCS bands (~2000 MHz) it would be > >> impractical due to size. > > > >[Moderator snip] > > > > I've dealt with hardline for amateur radio repeaters. Tough to work > > with but fairly low loss on 70cm. > > Everything is relative, compared to Radio Shack RG58 it certainly is > low loss :). > > Not all hardline is created equal, the 3dB I spec'ed is a typical "aim > point' for the cellular industry, when you get to the point feedline > losses exceed 3dB then you up to the next larger size line, with a > correspondingly lower loss. If you can get by with a smaller line > (less $$$) & not exceed the 3 db loss figure then you go with the > smaller line. If you've maxed out on size then you move up to an > air-dielectric cable which is even lower loss than the typical foam > core cable. > > H. > > ***** Moderator's Note ***** > > Compared to Radio Shack RG-58, Dixie cups and string are low loss! > > Bill Horne > Temporary Moderator > LOL on the RG-58 comment. We used Belden 9913 for most coaxial applications. But even that has a nominal loss of 2.6db per 100 feet at 400MHz. ------------------------------ Date: Tue, 05 May 2009 00:01:58 GMT From: Howard Eisenhauer <howarde@REMOVECAPShfx.eastlink.ca> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Waveguide (was "size a major consideration...") Message-ID: <n40vv4tuh4b6ad92oa9g7uc5ehkj2r7e8k@4ax.com> On Mon, 4 May 2009 09:24:28 -0400 (EDT), Neal McLain <nmclain@annsgarden.com> wrote: >I wrote: > > > I think what you're seeing on cell towers is flexible waveguide > > ("Heliax"): http://tinyurl.com/cudezg > >Howard Eisenhauer <howarde@REMOVECAPShfx.eastlink.ca> wrote: > > > Wave guide would be a lot more efficient but for the frequencies > > used for cellular (850-900 Mhz), or even the PCS bands (~2000 MHz) > > it would be impractical due to size. > > > "Heliax" (Andrews trade name) as used on cell towers is actually a > > hard line coax, not wave guide. There is a w/g product thats very > > hard to tell from the hardline from more than a few feet away but > > the w/g generally has an oval cross section where the hardline is > > round. The lowest frequency I've seen the w/g used for is 6 GHz. > >I stand corrected. *Snip* Understandable, "heliax" has attained about the same status as "asperin' or "kleenex". I had to stop & think for a moment on my original post to remember whether or not the "Heliax" trade name also applies to the w/g product. :/ H. ***** Moderator's Note ***** While "asperin" is safely in the public domain AFAIK, it seems that some other "generic" trademarks are coming back to life, like undead corpses in old movies: "Kerosene", which is "generic" in the United States, can't be used to refer to kerosene, because the word still enjoys trademark status in some countries. This caused a lot of confusion when the media started to cover conditions in African refugee camps: reporters would talk about a "Lack of cooking oil", but U.S. audiences were puzzled, because "cooking oil" means "vegetable oil" in the U.S., and most viewers thought the lack of vegetable oil wasn't anything that serious. It took several years, but now reporters covering refugee camps have learned to refer to kerosene as "cooking fuel", so that it's more clear what is being discussed. Bill "Your treasurehouse of trivia" Horne Temporary Moderator ------------------------------ Date: Mon, 4 May 2009 19:00:50 -0700 (PDT) From: hancock4@bbs.cpcn.com To: redacted@invalid.telecom.csail.mit.edu Subject: Re: FiOS in MDU Buildings Message-ID: <20b44e0d-3816-49ee-b0e5-196df721df8a@e20g2000vbc.googlegroups.com> On May 4, 9:23 am, "Tony Toews \[MVP\]" <tto...@telusplanet.net> wrote: > 8 Hours is a Long Time As stated, it's rare but it has happened. When a major storm hits, power is out for _days_; a really major storm, for _weeks_.. I watched them restring power wires after a bad storm, it is not trivial work. In such circumstances the telephone is needed more than ever. The traditional Central Office had a diesel generator in addition to its batteries, so a few days is not a problem. Eight hours is simply not enough. ***** Moderator's Note ***** I remember an occasion, when I was new to engineering, on which I remarked that the fuel tanks which fed a generator at a major SS7 office seemed to be unusually high off the ground. I was told it was because it's not possible to make them watertight. It took me about a week to figure out what had been said. Bill Horne Temporary Moderator ------------------------------ Date: Tue, 05 May 2009 03:03:32 GMT From: tlvp <PmUiRsGcE.TtHlEvSpE@att.net> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: AT&T doubling 3G capacity Message-ID: <op.utfr4eexwqrt3j@acer250.gateway.2wire.net> On Mon, 04 May 2009 14:01:56 -0400, Scott Dorsey <kludge@panix.com> wrote: > "C'est un Nagra. C'est suisse, et tres, tres precis." And it was developed by a disenchanted Polish emigre to Switzerland, named Kudelski, previously employed by the record company Polskie Nagranie. Donc c'est a la fois Suisse et Polonais :-) . Et ca te coute les yeux de la tete (French for "an arm and a leg", colloquially). The German outfit Uher produced a cheaper competitor (Uher 4000) that was so precise that if anything went even a tenth of a mm out of whack, the whole tape-transport mechanism was immobilized. No leeway or margins of error in their tolerances whatsoever. Cheers, -- tlvp ------------------------------ Date: Tue, 05 May 2009 09:42:40 -0700 From: Richard <rng@richbonnie.com> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Waveguide (was "size a major consideration...") Message-ID: <bfq0055se6j3d8qs9r0f8gd2rhtqhcub72@4ax.com> On Mon, 4 May 2009 15:26:43 -0400 (EDT), kludge@panix.com (Scott Dorsey) wrote: >I have seen 450MHz waveguide used for early satellite antenna systems. >It wasn't big enough to walk inside, but you could climb through it. >--scott For a really big waveguide, consider a highway tunnel. AM radio, at frequencies around 1 MHz, cannot penetrate the tunnel. But FM radio, at about 100 MHz, can penetrate. A 100 MHz signal has a wavelength of 3 meters, which is 10 feet. The cut-off frequency of a waveguide is that at which the longest dimension of the opening is 1/2 wavelength. For a 100 MHz signal, 1/2 wavelength is 5 feet, and any highway vehicle tunnel is larger that that. I have even picked up FM radio in the parking garage under Boston Common in Boston, MA. ***** Moderator's Note ***** ... which would mean waveguide for 450MHz would be about 13 inches wide, so that's not likely to be economical. The 23 cm band could be done with ~4.5 inches, but the price of copper is too high for that unless someone knows a way to do it with less expensive material. Bill Horne Temporary Moderator ------------------------------ TELECOM Digest is an electronic journal devoted mostly to telecom- munications topics. It is circulated anywhere there is email, in addition to Usenet, where it appears as the moderated newsgroup 'comp.dcom.telecom'. TELECOM Digest is a not-for-profit, mostly non-commercial educational service offered to the Internet by Patrick Townson. All the contents of the Digest are compilation-copyrighted. You may reprint articles in some other media on an occasional basis, but please attribute my work and that of the original author. The Telecom Digest is currently being moderated by Bill Horne while Pat Townson recovers from a stroke. Contact information: Bill Horne Telecom Digest 43 Deerfield Road Sharon MA 02067-2301 781-784-7287 bill at horne dot net Subscribe: telecom-request@telecom-digest.org?body=subscribe telecom Unsubscribe: telecom-request@telecom-digest.org?body=unsubscribe telecom This Digest is the oldest continuing e-journal about telecomm- unications on the Internet, having been founded in August, 1981 and published continuously since then. Our archives are available for your review/research. We believe we are the oldest e-zine/mailing list on the internet in any category! 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