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Hi-VHF 4-El K7MEM Yagi: Folded vs Not
Hi-VHF 4-Element Yagi Antennas - based on Dave47's antenna, designed per K7MEM (DL6WU) on-line calculator:
http://www.avsforum.com/avs-vb/showthread.php?p=13785312
http://www.avsforum.com/avs-vb/showthread.php?p=16552404

Compares 300-ohm Folded Dipole Yagi (Dave47's) to 75-ohm non-folded Yagi: essentially the same performance.
Same Boom Lengths=58.7-in.

Net Gain only covers Ch8 and Ch9.  Raw Gain extends throughout Ch10, but with excessive SWR.
So these 4-Element Yagis have LESS bandwidth than similar 8-Element Yagis.

NEC simulation normally does NOT include the boom.  When constructing a real antenna, a "Boom Correction"
is added to the length of each element to compensate for the additional loading from the metal in the boom,
but ONLY when using METAL boom construction.

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Hi-VHF 4-El K7MEM Folded Dipole Yagi vs
"Stick Dipole" Yagi: Essentially no difference.

Although Raw Gain covers Ch7-10, Net Gain is best
only over Ch8-9.  Rapidly falling Net Gain across
Ch10 can cause reception problems.


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4nec2 file: Dave47's 4-Element Folded Dipole Yagi
with 300-ohm characteristic impedance.


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4nec2 file: 4-Element "Normal, Thicker" Yagi
with 75-ohm characteristic impedance.


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Dave47's 4-El Folded Dipole Yagi - Gain

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Dave47's 4-El Folded Dipole Yagi - SWR

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Dave47's 4-El Folded Dipole Yagi - Impedance

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4-El "Normal" Yagi - Gain

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4-El "Normal" Yagi - SWR

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4-El "Normal" Yagi - Impedance

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