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Re:Sugnal Report

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  • zanzi1998
    But you still didn t answer my question about what is the best way to bond the two screens together. I m trying to make the 4228 more effective for receiving
    Message 1 of 37 , Dec 7, 2008
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      But you still didn't answer my question about what is the best way to bond
      the two screens together. I'm trying to make the 4228 more effective for
      receiving KNTV and KGO when the digital channel switches in February to
      channel 7.
    • Richard Swank
      The broadcast antennas are physically vertical looking but they transmit in the horizontal plane. All television stations are licensed to operate at their
      Message 37 of 37 , Dec 13, 2008
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        The broadcast antennas are physically vertical looking but they transmit in the horizontal plane.  All television stations are licensed to operate at their power in the horizontal plane if there is a vertical element that doesn’t count in operational power.  KNTV will replace the old top mount ch-11 antenna with a new ch-12 top mount antenna sometime in 2009 I believe (we will then have a main and standby antenna capable of 100% power operation) and when completed we will have the ability to have a 100% power in the vertical plane as well as the horizontal plane.  It is planned to operate that way as there are many indoor antenna users in the bay area (especially in SF) and to this point no one builds a good indoor VHF antenna.  By the way we currently operate at 25% vertical.


        From: HDTV-in-SFbay@yahoogroups.com [mailto: HDTV-in-SFbay@yahoogroups.com ] On Behalf Of Frank Nemec W6NJR
        Sent: Friday, December 12, 2008 8:34 AM
        To: HDTV-in-SFbay@yahoogroups.com
        Subject: [HDTV-in-SFbay] Re: Sugnal Report

         

        The screen is indeed aluminum. The product catalog says so, and nearly
        all residential TV antennas use aluminum elements for high conductivity
        and low cost and weight. But they're not so good for strength, so I
        would always lose about 3 long elements per season to the wind.
        Sometimes they anodize the aluminum, I think mainly because the gold
        finish looked better and sold better.

        The new model, the 4228HD, has close-spaced horizontal elements running
        the full width of the antenna. That makes it an almost perfect
        reflector for the horizontally- polarized component of the signal, nearly
        as good as a solid aluminum panel would be. The horizontal gap is
        mostly just a slightly wider gap than all the others. The 'driven'
        elements (the ones connected to the feedline) are also most sensitive to
        the horizontally- polarized component of the signal. That's why the
        horizontal gap wouldn't make much difference.

        That led me to wonder. Since all the TV antennas on Sutro are vertical,
        why don't we install these antennas vertically? I suspect the reason is
        that the vertical stacking makes the sensitivity pattern flat, like a
        horizontal pancake. You sacrifice the polarization match because for an
        antenna pointed north, extra sensitivity to the northeast and northwest
        is more useful than sensitivity toward the dirt and toward the north star.

        PS: Sorry for the confusion I caused regarding Nick Sayer's antenna
        setup. I was reading the compass bearing from him to the various
        stations, but I was mistakenly reading that from the distance column
        instead of the heading column.

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