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Re: [30MDG] 30/40 Meter Arrays, Status

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  • David Cole
    Hello Bill, I got lucky... The lot is long and narrow relative to itself, close to a 5:1 ratio... The lot is about 300 feet long, and about 60 feet wide, so
    Message 1 of 7 , May 14, 2013
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    Hello Bill,

    I got lucky... The lot is long and narrow relative to itself, close to
    a 5:1 ratio... The lot is about 300 feet long, and about 60 feet wide,
    so I can just get radials in place for both a 30 meter four square, and
    a 40 meter two element. Enclosed is a scaled map showing the antenna
    locations on the lot, and the radials needed, to scale. I have also
    added an image called "Array Context", showing the area for about 1/2
    mile around my home. As you can see, I am on the edge of a huge open
    area in the middle of a town... As I said, I got very lucky. My lot is
    defined by the "A", from Google.

    In the areas where the radials will be slightly short, (maybe 3 or 4
    feet short), I am not going o worry about them... As far as I can tell
    from about two weeks of heavy research, this will not make a major
    difference. The return currents on the radials are highest close to the
    antenna, and get lower as you go further out, so the effect of slightly
    shortened radials "should" not be an issue.

    It strikes me that a few shortened radials, while definitely making a
    difference, will be so small a difference so as not to worry about. I
    do worry about the pattern distortion though, but am not smart enough
    with EZNEC yet to be able to model the arrays, and one takes what one
    can get... In my case, I have been lucky so far...

    I intend to lay out radials until I get only small changes in R for each
    doubling of radials, as measured using an MFJ-259B... I will install
    the antenna and follow these steps:

    1. Take a R measurement.
    2. Double the radial count.
    3. Take another R measurement.
    4. If difference between last to R measurements is something small,
    then go to 6.
    5. Goto 2
    6. End

    As you can tell I used to program, and I find that it helps to formalize
    the steps being taken. In step 4, when I start approaching a less than
    10% change, as I approach 36 Ohms, I will start thinking about stopping.
    Once I get close to 36 Ohms... I'm done with radials...

    If for some reason I get lazy, I will put a lot of shortened radials in,
    as opposed to a few longer radials. Studies indicate that many shorter
    radials are better than a few long ones. This is caused by the return
    currents being highest near the base of the antenna, so more radials are
    more effective than a few long ones. I will not get lazy though, I want
    as perfect an array as possible for a ground mounted array, the thought
    of elevating the array, and having 10 or so radials did cross my head,
    but only for a moment...

    I will be taking out my trusty RF Ammeter to look at each antenna after
    the radials are in place... I want to insure the same power in each
    antenna.

    If you have any thoughts on this, good, or bad, please let me know
    sooner than later... That goes for anyone looking at this... I would
    much rather change plans prior to radial layout, than post radial
    layout.

    I purchased two miles of wire for the radial field... :)

    See:
    http://www.ncjweb.com/k3lcmaxgainradials.pdf
    and
    http://www.antennasbyn6lf.com/files/antenna_ground_system_experiment_2.pdf


    --
    Thanks,
    Dave
    For Amateur Radio equipment reviews and setups see:
    http://www.nk7z.net



    On Sun, 2013-05-12 at 16:47 -0700, W. J. Karle wrote:
    >
    >
    > Knowing that you are going with buried radials, I have a related
    > question.
    >
    >
    > It is difficult for me to determine, Dave, if the property is wide and
    > deep enough for a radial system of many (~32) quarter wave radials.
    > Is it? If not, what radial strategy are you planning?
    >
    >
    > 73,
    >
    >
    > Bill
    >
    >
    >
    >
    >
    >
    >
    >
  • W. J. Karle
    Dave: Thanks for your reply. The installation layout and your plan regarding when to stop laying radials both seem correct. Someone mentioned concerns about
    Message 2 of 7 , May 16, 2013
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      Dave:

      Thanks for your reply.

      The installation layout and your plan regarding when to stop laying radials both seem correct.

      Someone mentioned concerns about BCI/TVI to nearby neighbours but I imagine that should be less of a problem than heretofore since not too many receivers are operating with  7 and 10MHz IFs  (or a harmonic thereof), although some do.

      I have not run the curves but I wonder if neighbors' RF exposure will be below the published limits.

      We all will be following your path to success.  Good luck.

      73,

      Bill
       
      ------------------------------------------------------------------------------------------------------
      W. J. (Bill) Karle, VE4KZ
      Radio Amateurs of Canada -- Maple Leaf Operator Member
      Amateur Radio Emergency Service -- Certified Emergency Coordinator

      From: David Cole <dave@...>
      To: 30MDG@yahoogroups.com
      Sent: Tuesday, May 14, 2013 9:39:01 AM
      Subject: Re: [30MDG] 30/40 Meter Arrays, Status [1 Attachment]

      <*>[Attachment(s) from David Cole included below]

      Hello Bill,

      I got lucky...  The lot is long and narrow relative to itself, close to
      a 5:1 ratio...  The lot is about 300 feet long, and about 60 feet wide,
      so I can just get radials in place for both a 30 meter four square, and
      a 40 meter two element.  Enclosed is a scaled map showing the antenna
      locations on the lot, and the radials needed, to scale.  I have also
      added an image called "Array Context", showing the area for about 1/2
      mile around my home.  As you can see, I am on the edge of a huge open
      area in the middle of a town...  As I said, I got very lucky.  My lot is
      defined by the "A", from Google.

      In the areas where the radials will be slightly short, (maybe 3 or 4
      feet short), I am not going o worry about them...  As far as I can tell
      from about two weeks of heavy research, this will not make a major
      difference.  The return currents on the radials are highest close to the
      antenna, and get lower as you go further out, so the effect of slightly
      shortened radials "should" not be an issue.

      It strikes me that a few shortened radials, while definitely making a
      difference, will be so small a difference so as not to worry about.  I
      do worry about the pattern distortion though, but am not smart enough
      with EZNEC yet to be able to model the arrays, and one takes what one
      can get...  In my case, I have been lucky so far... 

      I intend to lay out radials until I get only small changes in R for each
      doubling of radials, as measured using an MFJ-259B...  I will install
      the antenna and follow these steps:

      1.  Take a R measurement.
      2.  Double the radial count.
      3.  Take another R measurement.
      4.  If difference between last to R measurements is something small,
      then go to 6.
      5.  Goto 2
      6. End

      As you can tell I used to program, and I find that it helps to formalize
      the steps being taken.  In step 4, when I start approaching a less than
      10% change, as I approach 36 Ohms, I will start thinking about stopping.
      Once I get close to 36 Ohms...  I'm done with radials...

      If for some reason I get lazy, I will put a lot of shortened radials in,
      as opposed to a few longer radials.  Studies indicate that many shorter
      radials are better than a few long ones.  This is caused by the return
      currents being highest near the base of the antenna, so more radials are
      more effective than a few long ones.  I will not get lazy though, I want
      as perfect an array as possible for a ground mounted array, the thought
      of elevating the array, and having 10 or so radials did cross my head,
      but only for a moment... 

      I will be taking out my trusty RF Ammeter to look at each antenna after
      the radials are in place...  I want to insure the same power in each
      antenna.

      If you have any thoughts on this, good, or bad, please let me know
      sooner than later...  That goes for anyone looking at this...  I would
      much rather change plans prior to radial layout, than post radial
      layout.

      I purchased two miles of wire for the radial field...  :)

      See:
      http://www.ncjweb.com/k3lcmaxgainradials.pdf
      and
      http://www.antennasbyn6lf.com/files/antenna_ground_system_experiment_2.pdf


      --
      Thanks,
      Dave
      For Amateur Radio equipment reviews and setups see:
      http://www.nk7z.net



      On Sun, 2013-05-12 at 16:47 -0700, W. J. Karle wrote:
      >
      >
      > Knowing that you are going with buried radials, I have a related
      > question.
      >
      >
      > It is difficult for me to determine, Dave, if the property is wide and
      > deep enough for a radial system of many (~32) quarter wave radials.
      >  Is it?  If not, what radial strategy are you planning?
      >
      >
      > 73,
      >
      >
      > Bill
      >
      >
      >
      >
      >
      >
      >
      >


      <*>Attachment(s) from David Cole:

      <*> 1 of 1 Photo(s) http://groups.yahoo.com/group/30MDG/attachments/folder/1396315328/item/list
        <*> array context.jpg

      ------------------------------------

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      http://hamspots.net/30mdg/




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    • W. J. Karle
      Dave, Following on my recent message, the RF Exposure calculator that I use is the one from ARRL.  It is at  http://hintlink.com/power_density.htm Bill  
      Message 3 of 7 , May 16, 2013
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        Dave,

        Following on my recent message, the RF Exposure calculator that I use is the one from ARRL.  It is at 

        Bill
         
        ------------------------------------------------------------------------------------------------------
        W. J. (Bill) Karle, VE4KZ
        Radio Amateurs of Canada -- Maple Leaf Operator Member
        Amateur Radio Emergency Service -- Certified Emergency Coordinator





      • David Cole
        Hi, Thank you! I found that one and ran the numbers, everything is contained within my yard, and behind a fence at acceptable levels!! :) I used 1500 W for 7
        Message 4 of 7 , May 16, 2013
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          Hi,

          Thank you! I found that one and ran the numbers, everything is
          contained within my yard, and behind a fence at acceptable levels!! :)
          I used 1500 W for 7 MHz., and 3 db gain, and 200 for 10 MHz. at 6 db.
          --
          Thanks,
          Dave
          For Amateur Radio equipment reviews and setups see:
          http://www.nk7z.net



          On Thu, 2013-05-16 at 18:07 -0700, W. J. Karle wrote:
          >
          >
          > Dave,
          >
          >
          > Following on my recent message, the RF Exposure calculator that I use
          > is the one from ARRL. It is at
          > http://hintlink.com/power_density.htm
          >
          >
          >
          > Bill
          >
          >
          > ------------------------------------------------------------------------------------------------------
          > W. J. (Bill) Karle, VE4KZ
          > Radio Amateurs of Canada -- Maple Leaf Operator Member
          > Amateur Radio Emergency Service -- Certified Emergency Coordinator
          >
          >
          > ______________________________________________________________________
          >
          >
          >
          >
          >
          >
          >
          >
        • David Cole
          Hi, Thank you! The rains have returned with a vengeance here for now... I expect a few more days of rain, (should make the ground soft for radial, and
          Message 5 of 7 , May 16, 2013
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            Hi,

            Thank you! The rains have returned with a vengeance here for now... I
            expect a few more days of rain, (should make the ground soft for radial,
            and cabling), then I'll start the next phase, of getting Feed lines in
            conduit, and radials down for Antenna #1. Once #1 is running fine, I'll
            install #2. Same steps, and that should finish the 40 meter portion...
            I am a bit worried about my GAP sitting just under 1.4 wave away... If
            it gets it the way, I'll move it... :)
            --
            Thanks,
            Dave
            For Amateur Radio equipment reviews and setups see:
            http://www.nk7z.net



            On Thu, 2013-05-16 at 17:34 -0700, W. J. Karle wrote:
            >
            >
            > Dave:
            >
            >
            > Thanks for your reply.
            >
            >
            > The installation layout and your plan regarding when to stop laying
            > radials both seem correct.
            >
            >
            > Someone mentioned concerns about BCI/TVI to nearby neighbours but I
            > imagine that should be less of a problem than heretofore since not too
            > many receivers are operating with 7 and 10MHz IFs (or a harmonic
            > thereof), although some do.
            >
            >
            > I have not run the curves but I wonder if neighbors' RF exposure will
            > be below the published limits.
            >
            >
            > We all will be following your path to success. Good luck.
            >
            >
            > 73,
            >
            >
            > Bill
            >
            >
            > ------------------------------------------------------------------------------------------------------
            > W. J. (Bill) Karle, VE4KZ
            > Radio Amateurs of Canada -- Maple Leaf Operator Member
            > Amateur Radio Emergency Service -- Certified Emergency Coordinator
            >
            >
            > ______________________________________________________________________
            >
            > From: David Cole <dave@...>
            > To: 30MDG@yahoogroups.com
            > Sent: Tuesday, May 14, 2013 9:39:01 AM
            > Subject: Re: [30MDG] 30/40 Meter Arrays, Status [1 Attachment]
            >
            >
            > Hello Bill,
            >
            > I got lucky... The lot is long and narrow relative to itself, close
            > to
            > a 5:1 ratio... The lot is about 300 feet long, and about 60 feet
            > wide,
            > so I can just get radials in place for both a 30 meter four square,
            > and
            > a 40 meter two element. Enclosed is a scaled map showing the antenna
            > locations on the lot, and the radials needed, to scale. I have also
            > added an image called "Array Context", showing the area for about 1/2
            > mile around my home. As you can see, I am on the edge of a huge open
            > area in the middle of a town... As I said, I got very lucky. My lot
            > is
            > defined by the "A", from Google.
            >
            > In the areas where the radials will be slightly short, (maybe 3 or 4
            > feet short), I am not going o worry about them... As far as I can
            > tell
            > from about two weeks of heavy research, this will not make a major
            > difference. The return currents on the radials are highest close to
            > the
            > antenna, and get lower as you go further out, so the effect of
            > slightly
            > shortened radials "should" not be an issue.
            >
            > It strikes me that a few shortened radials, while definitely making a
            > difference, will be so small a difference so as not to worry about. I
            > do worry about the pattern distortion though, but am not smart enough
            > with EZNEC yet to be able to model the arrays, and one takes what one
            > can get... In my case, I have been lucky so far...
            >
            > I intend to lay out radials until I get only small changes in R for
            > each
            > doubling of radials, as measured using an MFJ-259B... I will install
            > the antenna and follow these steps:
            >
            > 1. Take a R measurement.
            > 2. Double the radial count.
            > 3. Take another R measurement.
            > 4. If difference between last to R measurements is something small,
            > then go to 6.
            > 5. Goto 2
            > 6. End
            >
            > As you can tell I used to program, and I find that it helps to
            > formalize
            > the steps being taken. In step 4, when I start approaching a less
            > than
            > 10% change, as I approach 36 Ohms, I will start thinking about
            > stopping.
            > Once I get close to 36 Ohms... I'm done with radials...
            >
            > If for some reason I get lazy, I will put a lot of shortened radials
            > in,
            > as opposed to a few longer radials. Studies indicate that many
            > shorter
            > radials are better than a few long ones. This is caused by the return
            > currents being highest near the base of the antenna, so more radials
            > are
            > more effective than a few long ones. I will not get lazy though, I
            > want
            > as perfect an array as possible for a ground mounted array, the
            > thought
            > of elevating the array, and having 10 or so radials did cross my head,
            > but only for a moment...
            >
            > I will be taking out my trusty RF Ammeter to look at each antenna
            > after
            > the radials are in place... I want to insure the same power in each
            > antenna.
            >
            > If you have any thoughts on this, good, or bad, please let me know
            > sooner than later... That goes for anyone looking at this... I would
            > much rather change plans prior to radial layout, than post radial
            > layout.
            >
            > I purchased two miles of wire for the radial field... :)
            >
            > See:
            > http://www.ncjweb.com/k3lcmaxgainradials.pdf
            > and
            > http://www.antennasbyn6lf.com/files/antenna_ground_system_experiment_2.pdf
            >
            >
            > --
            > Thanks,
            > Dave
            > For Amateur Radio equipment reviews and setups see:
            > http://www.nk7z.net
            >
            >
            >
            > On Sun, 2013-05-12 at 16:47 -0700, W. J. Karle wrote:
            > >
            > >
            > > Knowing that you are going with buried radials, I have a related
            > > question.
            > >
            > >
            > > It is difficult for me to determine, Dave, if the property is wide
            > and
            > > deep enough for a radial system of many (~32) quarter wave radials.
            > > Is it? If not, what radial strategy are you planning?
            > >
            > >
            > > 73,
            > >
            > >
            > > Bill
            > >
            > >
            > >
            > >
            > >
            > >
            > >
            > >
            >
            >
            >
            > ------------------------------------
            >
            > Please join in with us on the 30 Meter Band. When in the shack use the
            > 30 mtr digital Spots page made possible by Laurie VK3AMA
            >
            > http://hamspots.net/30mdg/
            >
            >
            >
            >
            > Yahoo! Groups Links
            >
            >
            >
            >
            >
            >
            >
            >
            >
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