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2 METER 1/2-WAVE J-POLE
VHF-FM Antenna Made From 450-Ohm LADDER LINE
Great first time J-pole project.  Covers most of the basics.
This small and thin design also makes it good for several stealth applications.
And......We've nicknamed this design the "LL-Coool-J"

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Reminder: Always ID your station when testing...
 Technical Data: Ref.:V1.02; ID:LL-coool-j; Dated:08/04/03 Velocity Factors Estimated: Open Wire@ 98% (insulation removed; as used in upper element section) Insulated 450-Ohm Ladder Line@ 92% (as used in lower matching section) Element Length Predictions: 1/2 Wavelength @ 98% = 39.63" +/- 1%  (146.000MHz @ 40.44" in free space) 1/4 Wavelength @ 92% = 18.60" +/- 1%  (146.000MHz @ 20.22" in free space) Lower Folded 1/2 Wave Matching Section = 1/4 Wavelength in this calculation

 More information to help you build this J-pole antenna for other frequencies: 5/8 Wavelength Formulas: "615" divided by the frequency in Megahertz (this # is in feet) (and multiplied by 12 inches) = the free space 5/8 Wavelength in inches (and then multiplied by the Velocity Factor %) = electrical 5/8 Wavelength in inches or 615/MHz x 12 x VF = electrical 5/8 Wavelength in inches 1/2 Wavelength Formulas: "492" divided by the frequency in Megahertz (this # is in feet) (and multiplied by 12 inches) = the free space 1/2 Wavelength in inches (and then multiplied by the Velocity Factor %) = electrical 1/2 Wavelength in inches or 492/MHz x 12 x  VF = electrical 1/2 Wavelength in inches 1/4 Wavelength Formulas: "246" divided by the frequency in Megahertz (this # is in feet) (and multiplied by 12 inches) = the free space 1/4 Wavelength in inches (and then multiplied by the Velocity Factor % ) = electrical 1/4 Wavelength in inches  or 246/MHz x 12 x VF = electrical 1/4 Wavelength in inches
Editor's Notice:

Please check out N4UJW's "Hamuniverse.com": http://www.hamuniverse.com
Don N4UJW has a lot of great antenna projects information..
All kinds of interesting and unique ideas!  Stuff you won't find anywhere else..  Just great information!!