Mark,
If you are using a 1/2 wave dipole the wire on the ground should be
unbroken and 5% longer. You can run two or three parallel wires spaced
a few feet apart or just one wire.
If you are using a full wave dipole then the reflector should be broken
in the center. You're basically feeding two half wave antennas and the
reflectors should be independent.
My 2 Cents,
dave
wa3gin
Mark . wrote:
>Hi All,
>All this talk lately of NVIS antenna work goes along with some antennas and
>masts I have been building lately to enjoy casual, portable hamming, with
>some emphasis on cheap antenna plans for a cheap emergency 80 trunk antenna.
>So far, results have been quite good using 18ga lamp cord or speaker cord,
>using a 30' or less of the unzipped portion as a feedline, to a 4:1 current
>balun and then connected to the mobile HF rig.
>
>I once read that an old trick for boosting the efficiency of horizontal
>antennas over questionalble ground was to run a series of radials along the
>ground parallel to the antenna.
>
>For instance, if the antenna is a flat-top or inverted Vee, run 4-5 radials
>parallel to it along the ground, spaced 10-15 few feet apart.
>
>This is pretty easy to accomply by unrolling precut wires from a homemade
>spool (you can get free plastic spools by asking for the empty ones at the
>home stores from their rotary wire supply racks).
>
>What is an effective placement for such wires under the antennas? Any rules
>of thumb for length and orientation?
>
>If separate wires, do they need to be approximately 5% longer than the
>driven antenna to act as reflectors?
>
>It would be convenient to just have a long wire on a spool and lay out a
>zig-zag pattern around temporary stakes, such that you could just walk
>around and pay out the line from the spools. Winding them up would be a
>snap, too.
>
>Thanks for your ideas.
>
>--...MARK_N1LO...--
>
>
>_______________________________________________
>
>See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
>Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
>questions and ask for Sherman, W2FLA.
>
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>
>
>
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
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