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SSTV

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  • Sholto Fisher
    Hi all, I just wanted to mention that I found out today that there are 6 narrow bandwidth SSTV modes in the free MMSSTV software which can be downloaded from
    Message 1 of 48 , Jan 20, 2008
      Hi all,

      I just wanted to mention that I found out today that there are 6 narrow
      bandwidth SSTV modes in the free MMSSTV software which can be downloaded
      from http://mmhamsoft.amateur-radio.ca/mmsstv/

      The scan signals occupy 2044Hz - 2300Hz and the sync is at 1900Hz. The whole
      thing is 400Hz wide.

      MP73-N (320x256) 73 seconds
      MP110-N (320x256) 110 seconds
      MP140-N (320x256) 140 seconds
      MC110 (320x256) 110 seconds
      MC140 (320x256) 140 seconds
      MC180 (320x256) 180 seconds

      I can see no reason why these modes are not legal on 30m in FCC areas
      (certainly, MFSK SSTV is allowed) - if anybody thinks different let me know!
      but assuming I am correct I suggest we could add these to our list of modes
      to try.

      It would be possible to make contact either by initially sending an SSTV CQ
      picture and continue that way or to initiate contact with a digimode first
      (perhaps DominoEX, a 500Hz Olivia mode or even PSK31 if you remember that
      you will need at least 400Hz of empty spectrum for the transmission so watch
      out for adjacent signals. I would suggest that your digimode AF center
      should be 2100Hz which would put it right in the middle of the (to be
      transmitted) SSTV passband.

      If you have Windows XP you can use the same soundcard in different software
      programs at the same time which would allow you to run MixW/MultiPSK (for
      the initial digimode) and MMSSTV together - just switch to MMSSTV when you
      want to send the picture.

      The MMSSTV software includes a FSKID which can be used to send callsign info
      after a picture has been sent and also a VIS code (transmitted at the start
      of the picture) which allows automatic mode determination.

      If there is enough interest in operating SSTV perhaps the group as a whole
      (democratically!) could determine a possible calling frequency which would
      encourage operation at a known reference point (similar to the 14.230 spot
      frequency on 20m).

      Here's to some interesting "multimedia" QSOs on 30m!

      73, Sholto KE7HPV
    • VE3FAL-Fred
      What I have done is used clothes line wire in the trees I wish to hang my wire. I then attach it to the antenna at the point I wish to bring up, I then tie
      Message 48 of 48 , Feb 21, 2011
        What I have done is used clothes line wire in the trees I wish to hang my
        wire. I then attach it to the antenna at the point I wish to bring up, I
        then tie bricks or some kind of weith to the bottom of the clothes line so
        it will sway in the tree with very little pulling of the antenna it self. We
        have very tall poplar , spruce and pine trees in my area, and I find the
        plastic coated clothes line wire because it does move will not grow into the
        tree like robe or other tiedowns will do..


        Fred
        YouKits Canada Rep.
        http://www.youkits.com
        CIW649/VE3FAL
        CFARS Member
        SATERN Member
        SATERN Amateur Radio Liaison Officer Great Lakes Region
        http://www.satern.org
        DEC Amethyst District ARES
        http://www.thunderbay.emergencyradio.ca/

        On Tue, 22 Feb 2011 01:08:31 +0000
        Scott Currier <scott_currier@...> wrote:

        I haven't got the perfect solution but after years of using copper wire
        for
        antennas I have come to the conclusion that you don't use copper wire with
        supports that move. Everytime I had a problem, the antenna wire broke, not
        the
        rope.

        I now use copper clad steel wire and a lot of extra rope.

        I also let the antenna hang down a bit rather than pull it tight.

        The idea is that the copper clad steel is strong and the extra rope is to
        allow for stretching if the trees move in opposite directions.

        Rather than having the antenna break to spare the rope, I'd rather have
        the
        rope stretch and the whole setup remain up in the trees. If something is
        going
        to break, I'd prefer it to be the rope.

        I had a email conversation with a small antenna mfg, I forget who he was,
        but
        he was offering an antenna I was interested in but it was made of copper
        rather than steel wire and he didn't or wouldn't do a version with copper
        clad
        steel wire so I didn't buy it.

        The antenna I have now came as copper wire but it is a single wire design
        so
        I just ordered enough copper clad steel wire and rebuilt it.

        All my antennas now will be made with the copper clad steel.

        Took me a long time to learn something so simple. Oh well.

        73 all and good dx.

        Scott KT1B Haverhill, MA

























        To: 30MDG@yahoogroups.com
        From: djch-yahoo@...
        Date: Tue, 22 Feb 2011 00:26:12 +0000
        Subject: Re: [30MDG] Re: Antenna in swaying tree, was : SSTV






        Daithi

        I second the idea of bungee cord. It has a limited life in sunsine, but I
        get
        several years each....

        Using a weight is a bad idea, in that if the tree hits a sudden gust the
        weight can free fall, and then it snatches as the wire goes tight (or
        alternatively the antena holds the tree still for a moment for the other
        direction of gust...) Both generate avoidable shock loads in the winds we
        get.
        (I fear bungee would fail to operate if it was soaking wet and then it froze
        solid, so might be a problem in severe winters. But then, the pulley may ice
        up, or the wires.)

        73

        --David

        On Sun, 20 Feb 2011 14:12:20 -0000
        "Daithi" <gi7omy@...> wrote:

        > What I have done with wires was to use a bungee cord (the sort of elastic
        > rope with hooks at each end that you use to hold luggage on a car roof rack
        > or a motor bike pillion). They will keep tension but will also stretch when
        > needed
        >
        >
        >
        > 73 de Daithi
        >

        --
        <djch-yahoo@...>
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