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The formulas
for calculating T2FD dimensions are as follows.
1. The
length of each leg ("A'') from the center is equal to 50,000 divided
by the lowest desired operating frequency (in kHz) and then multiplied
by 3.28. The answer is in feet.
2. The
spacing between radiating wires ("B") is equal to 3000 divided
by the lowest desired operating frequency (in kHz) and then multiplied
by 3.28. The answer is in feet.
3.
The sloping angle for a nondirectional pattern should be
on the order of 30, but 20–40 is acceptable.
Example:
To design a T2FD for the center of the 90 meter band (3300 kHz)
and up:
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Desired
frequency
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Spacing
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Leg
"A"
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(50.000 / 3300) x 3.28
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49.70 feet
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Leg
"B"
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(3000 / 3300) x 3.28
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2.98 feet
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Total length
of the antenna would be 99.4 feet (2 x 49.7), and the width would
be 2.98 feet ("B").
The total
wire used to complete the loop equals 204.76 feet (4 x 49.7)
+ (2 x 2.98).
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Copyright worldwide by Proceedings
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