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Re: AT&T Plano, IL

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  • ozob99@yahoo.com
    ... multiplexing, ... the ... Central ... well ... Another analogy came to mind since you mentioned some cable pair carriers;a non-loaded 19 gauge cable pair
    Message 1 of 10 , Nov 4, 2001
      --- In coldwarcomms@y..., ozob99@y... wrote:
      > --- In coldwarcomms@y..., Harold Peach <hpeach@p...> wrote:
      > > As I understand it, Coax-8, Coax-12, and Coax-20 defined the cable
      > type. A,
      > > N, K, L3, Improved L3, L4, and L5 were multiplexing standards. The
      > > multiplexing standard required a certain diameter individual
      > coaxial, but
      > > not a certain cable type. So, while L3 multiplexing usually used
      > Coax-8
      > > cable; Improved L3, Coax-12; and L4, Coax-20, this was not a
      > requirement.
      > > An example is how the Airmont to Mojave transcontinental route
      > consisted of
      > > a Coax-12 cable type that originally used Improved L3
      multiplexing,
      > but was
      > > later upgraded to P-140 multiplexing.
      >
      >
      >
      > The multiplexing scheme or bandwidth was not the critical factor;
      > the line bandwidth required an optimal impedence and minimal SWR for
      > lowest transmission loss ;the diameter was critical for "corona",
      the
      > arcing point of the power feed voltage,which varied on power
      > loops.L1/L3 used AC voltages up to 1800; L4 used DC up to 1200-1500
      > as best I remember.The original L1 tube was .270 diameter, and some

      > L3 overbuilds used existing cable of this diameter instead of laying
      > new L3 standard cable of .375(e.g. Richmond-Faulkner).In older
      Central
      > Offices you may find broadband(MG/MMX) connections up to the cable
      > terminal using older RG type 75 ohm coax about 3/8" diameter, as
      well
      > as the modern "mini" coax of about 1/8" diameter used since the
      > 1960's.
      >

      > I recall there were a few 22 tube L4/5 cables.
      >
      > Phillips P-140 was also used on some L4 20 tube cables.



      Another analogy came to mind since you mentioned some cable pair
      carriers;a non-loaded 19 gauge cable pair served as a transmission
      medium for K,N,N2,N3,ON,Lenkurt,Collins,Lynch,et al carrier systems,
      using different bandwidths,modulation schemes,etc.The repeater spacing
      & equalization differed with each of course, but the "line" was
      campatible with all.





      >
      >
      >
      >
      >
      > >
      > > At 04:04 PM 11/4/2001 -0500, you wrote:
      > > >At 08:41 PM 11/4/2001 +0000, you wrote:
      > > > >including a rare 20 tube
      > > > >L3(perhaps the only one),to Norway I think;& I believe there
      were
      > GEP
      > > > >antennae on the tower.
      > > >
      > > >How about a 6 tube L4 from Cheshire to Greenhill?
      > > >
      > > >
      > > >
      > > >Your use of Yahoo! Groups is subject to
      > http://docs.yahoo.com/info/terms/
    • dsandow@garden.net
      ... Indeed there was a reason. TAT-5 (Greenhill RI) was built during the height of the cable vs. satellite era. Every additional overseas facility had to go
      Message 2 of 10 , Nov 5, 2001
        >
        > OK, just seemed strange, I assume there must have been a reason to
        > make a short section of 6 tube cable;perhaps to interface with that
        > particular TAT cable.

        Indeed there was a reason.

        TAT-5 (Greenhill RI) was built during the height of the cable vs.
        satellite era. Every additional overseas facility had to go through
        a rigorous adversarial proceeding before the FCC, to "protect" Comsat.

        On one side, ATT (proven reliability of cable), the record carriers
        (data comm was not happy about the round-trip delay of satellite),
        and DoD (survivability, privacy and round-trip data).

        On the other side, Comsat (formed in 1964 to evolve the technology
        invented by ATT with Telstar in 1962), the earth station vendors
        (looking for overseas sales) and the State Department (which was
        gung-ho about the international satellite treaties with everybody,
        and did not want to see USA lose out on its satellite leadership
        because COMSAT couldn't maintain its dominance if it couldn't get USA
        traffic streams onto satellite (at the expense of cable streams)).

        So the traffic was to be split 50-50, and every Construction
        Authorization was severly restrictive about how much capacity could
        be built, equipped, and fired up (not always the same!). The
        6-tube entrance link to the cable station was "collateral damage".
        ATT was only allowed to build as much cable into the cable station as
        was needed to connect to the "authorized" underseas cable. And
        "unequipped tubes" could not possibly be allowed, since ATT might
        cheat some day and try to sneak in another underseas cable. No sir,
        don't build ANYTHING more than we give you permission to build.

        This same logic prevailed when ATT built its first fiber TAT. It was
        a 6 strand cable. 2 strands (1 T/R pair) for UK, 2 for France, 2 for
        protection switching. None for growth.

        (For historical perspective, the FCC of the late '60s early '70s had
        not shaken off the momentum from the policies created during the LBJ
        era - "Remember guys - I own a TV station - go find something else to
        regulate.")
      • ozob99@yahoo.com
        ... that ... Comsat. ... USA ... as ... to ... OK, sounds familiar;unreasonable but reasonable for politics...there was a crash program in the 1970 s to get
        Message 3 of 10 , Nov 5, 2001
          --- In coldwarcomms@y..., dsandow@g... wrote:
          > >
          > > OK, just seemed strange, I assume there must have been a reason to
          > > make a short section of 6 tube cable;perhaps to interface with
          that
          > > particular TAT cable.
          >
          > Indeed there was a reason.
          >
          > TAT-5 (Greenhill RI) was built during the height of the cable vs.
          > satellite era. Every additional overseas facility had to go through
          > a rigorous adversarial proceeding before the FCC, to "protect"
          Comsat.
          >
          > On one side, ATT (proven reliability of cable), the record carriers
          > (data comm was not happy about the round-trip delay of satellite),
          > and DoD (survivability, privacy and round-trip data).
          >
          > On the other side, Comsat (formed in 1964 to evolve the technology
          > invented by ATT with Telstar in 1962), the earth station vendors
          > (looking for overseas sales) and the State Department (which was
          > gung-ho about the international satellite treaties with everybody,
          > and did not want to see USA lose out on its satellite leadership
          > because COMSAT couldn't maintain its dominance if it couldn't get
          USA
          > traffic streams onto satellite (at the expense of cable streams)).
          >
          > So the traffic was to be split 50-50, and every Construction
          > Authorization was severly restrictive about how much capacity could
          > be built, equipped, and fired up (not always the same!). The
          > 6-tube entrance link to the cable station was "collateral damage".
          > ATT was only allowed to build as much cable into the cable station
          as
          > was needed to connect to the "authorized" underseas cable. And
          > "unequipped tubes" could not possibly be allowed, since ATT might
          > cheat some day and try to sneak in another underseas cable. No sir,
          > don't build ANYTHING more than we give you permission to build.
          >
          > This same logic prevailed when ATT built its first fiber TAT. It was
          > a 6 strand cable. 2 strands (1 T/R pair) for UK, 2 for France, 2 for
          > protection switching. None for growth.
          >
          > (For historical perspective, the FCC of the late '60s early '70s had
          > not shaken off the momentum from the policies created during the LBJ
          > era - "Remember guys - I own a TV station - go find something else
          to
          > regulate.")


          OK, sounds familiar;unreasonable but reasonable for politics...there
          was a crash program in the 1970's to get thousands of domestic PSN
          circuits rerouted onto satellite just to fill it up for regulatory
          reasons; then later they were rerouted back on L & radio...btw some
          of these circuits were split,transmit & rec, between the bird &
          terrestial,creating tricky echo cancelling schemes.
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