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Re: [coldwarcomms] Thurmont, MD passive repeater

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  • Patton Turner
    ... Double billboards are quite rare, as usually you can find a better location for a passive. There is one other kind of passive - two back to back dishes.
    Message 1 of 4 , May 5, 2000
      At 09:58 PM 4/21/00 -0400, you wrote:

      >
      >Elsewhere, a double repeater is illustrated. It appears as two
      >"billboards" facing each other, their reflecting surfaces almost parallel.
      >The article explains that the distance between the paired reflectors is not
      >extremely critical; it may be from under 100 feet to over a mile or more
      >with little effect on performance.

      Double billboards are quite rare, as usually you can find a better location
      for a passive.

      There is one other kind of passive - two back to back dishes. It has much
      lower wind loading for the same performance, but won't acheve as much gain
      as a big reflector. The upside is a 180 degree angle works as well as a 5
      degree one. Path alignment can be a royal PITA (4 antennas, 8 degrees of
      freedom) unless you take a Spec-An up the passive tower.

      >
      >Since we haven't seen a "mate" for the Piney Mountain reflector, the
      >135-degree angle limitation should help narrow down the possible
      >destinations.

      Pat


      >
      >...Albert
      >
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      >
    • Albert LaFrance
      Pat, ... location ... Thanks for the info on that type of passive repeater. Mark Foster notes such a repeater was installed at the USAF s The Notch PACCS
      Message 2 of 4 , May 11, 2000
        Pat,

        >Double billboards are quite rare, as usually you can find a better
        location
        >for a passive.
        >
        >There is one other kind of passive - two back to back dishes. It has much
        >lower wind loading for the same performance, but won't acheve as much gain
        >as a big reflector. The upside is a 180 degree angle works as well as a 5
        >degree one. Path alignment can be a royal PITA (4 antennas, 8 degrees of
        >freedom) unless you take a Spec-An up the passive tower.

        Thanks for the info on that type of passive repeater. Mark Foster notes
        such a repeater was installed at the USAF's "The Notch" PACCS facility in
        Hadley, MA:

        http://www1.shore.net/~mfoster/PACCS.htm

        ...Albert
      • Albert LaFrance
        A while ago I posted information about a passive microwave repeater atop Piney Mountain, north of Thurmont, MD. A person familiar with the installation has
        Message 3 of 4 , Jul 19 7:27 PM
          A while ago I posted information about a passive microwave repeater atop
          Piney Mountain, north of Thurmont, MD.

          A person familiar with the installation has identified it as a Bell
          Atlantic repeater, part of a 6-GHz link between Thurmont and Frederick, MD.
          The link has been decommissioned but the repeater was allowed to remain,
          due to the expense of removing it.

          I've updated my Cold War web page to include this new infromation, and have
          moved the web page for the repeater to my Bell System site.

          Albert
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