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Short 20m Dipole Project

Posted: 30 Apr 2018, 14:48
by Buick Mackane
Thought i would share some construction details of a homebrew 8 foot long loaded dipole that i recently knocked up for the 20m band. The overall length of each element is 4 foot including the loading coils, Which are placed 2 foot from the feedpoint. The inductance of the coils is 16uh (microhenries) Cant tell you the exact number of turns as i never counted them.

The exact number of turns will depend on the gauge of wire you use, I used 16 AWG Speaker wire. Using thick wire is preferable as it helps to widen the bandwidth.

Also the placement of the coils also effects bandwidth, If you place them closer to the feedpoint you'll need less inductance, (Less bandwidth) Nearer to the ends of the elements requires more inductance, (More bandwidth) Best to keep them centred.

Ofcourse you can make it as short/long as you want to. Making it shorter requires more inductance, Longer = less inductance.

You can make it for any band, But you'll need to do the maths, Theres a few online loading coil calculators that put you in the ball park,

Having an inductance meter makes things a lot easier,

Mine has a Bandwidth of roughly 180 khz

14.150 = SWR 2.0
14.240 = SWR 1.1
14.330 = SWR 2.0

Happy Homebrewing :)