From: telecomdigestsubmissions@remove-this.telecom-digest.org   
      
   On Fri, Apr 01, 2022 at 08:52:33AM -0400, Fred Goldstein wrote:   
   > On 3/31/2022 11:39 AM, Bill Horne wrote:   
   > >...   
   > >Perhaps you will be able to make more sense out of it. My circuit   
   > >breaker has tripped.   
   > >   
   > >Bill   
   > >   
   > >- - - - - - - - - - - - - - - - - - - - - - - - - - -   
   > >   
   > >"An official website of the United States government"   
   > >   
   > >What's the news? AT&T is America's public safety communications   
   > >partner. In the nearly 5 years since we were selected by the First   
   > >Responder Network Authority (FirstNet Authority) to build and operate   
   > >FirstNet(r), we have moved quickly to bring more coverage, boost   
   > >capacity and drive new capabilities for South Carolina first   
   > >responders and the communities they serve - rural or urban.   
   >   
   > I'm not exactly an uncritical fan of FirstNet, having been fairly   
   > close to the process that created it, and having worked with real   
   > public safety communications. There was a real mess in the 2005-2009   
   > time frame, not worth recounting here, and it basically ended with   
   > AT&T picking up the pieces. But the idea is not bad and it could be   
   > useful.   
      
   One of the things that happens when I take a vacation from the Digest   
   is that I come back to work with "new eyes" - I notice things that   
   weren't grabbing my attention before, and I've just realized that I   
   don't know as much about radio and Cellular technology as I had   
   thought I did.   
      
   Ergo, I'll ask you to give us more detail about the underlying   
   technology behind FIrstNet(R), and to explain some of the acronyms   
   that have been mentioned. I hate to do it, but I'll (respectfully)   
   request an "Executive Overview" that gives a layman's view of the   
   possibilities and problems.   
      
   > FirstNet is a "broadband" public safety network intended to complement   
   > the "narrowband" voice walkie-talkie systems that first responders   
   > (police, fire, EMS) typically carry.   
      
   OK, here's my first double-take: my only experience with two-way radio   
   technology, outside Amateur radio, was fixing the radios in the snow   
   plows and staff cars used by the Commonwealth of Massachusetts, back   
   in 1972. At that time, "Narrowband" was what we called FM two-way   
   radios that were set for plus-and-minus 5KHz deviation. However, I've   
   been told that "Narrowband" now refers to radio transmitters using   
   plus-and-minus 2.5KHz deviation, and "Wideband" is the older +/- 5KHz   
   system.   
      
   Pleae tell us if I'm right, and what that change did to increase the   
   available bandwidth in the bands used by First Responders, and why   
   FirstNet is considered "Wideband."   
      
   > It's basically a 700 MHz LTE network, where the 700 MHz band has   
   > good indoor and cluttered-area coverage. The idea is that AT&T gets   
   > to use the spectrum for commercial (cellular) customers, but   
   > reserves and prioritizes its use for first responders when they need   
   > it. FirstNet's customers, the first responders, pay for the service,   
   > which allows them to download images and video, which could help   
   > them in their front line work.   
      
   IIRC, 700 MHz was the range used for "trunked" two-way push-to-talk   
   systems: I thought it was still being used for that. Correct me if I'm   
   wrong, though: didn't T-Mobile have it's "Push-To_Talk" service in   
   that band as well?   
      
   And, Ghod forgive me, I have to ask what "LTE" means in this   
   context. Trunked radio systems are now decades old, so if that's what   
   AT&T is calling "Long Term Evolution," well, I want my tax money back.   
      
   > Not all first responders buy into this; real-world police in many   
   > places, for instance, carry ordinary smartphones, which generally work   
   > fine. But in some places where cell coverage is spotty, FirstNet gives   
   > AT&T an incentive to build out, and it gives local governments an   
   > incentive to permit the necessary towers to be built. Whether that's   
   > good or bad is a matter of perspective...   
      
   Let's pull over into the learning lane for a moment, and I'll ask a   
   few questions I hope will clarify what is going on.   
      
   1. Is FirstNet(R) a service that uses single-channel radios, like the   
      ones that Police used to have for their exclusive use, or is it for   
      "trunked" radios like the ones taxicabs, courier services, and   
      delivery trucks use now? Some Police and Fire departments have   
      switched to "trunked" systems, because some municipalities have   
      combined all their departments onto a single "trunked" system in an   
      effort to save money.   
      
   2. If FirstNet is a "Wideband" service that allows First Responders to   
      "download images and video," how can it be shared with older   
      "narrowband" Release-To-Listen users? Are there multiple systems with   
      different capabilities sharing the FirstNet band(s)?   
      
   3. Unless I misunderstand the FirstNet PR, the system is equipped to   
      allow First Responders to interrupt existing "other" users when   
      First Responders make a call. Is that correct? Is there any public   
      info you can point us to?   
      
   Thanks for your help. I'm sorry to have to ask what are probably very   
   basic questions to you, but I need to have a common basis of under-   
   standing if the Digest is to have cogent threads about issues and   
   systems such as FirstNet.   
      
   Bill   
      
   --   
   Bill Horne   
   Telecom Digest Moderator   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)