[TowerTalk] FW: Vertical dipole other choices?

[David Gilbert]

That's not really a J-Pole.  A J-Pole generally has a 1/2 wave vertical 
section, not a 1/4 wave.  Since the end of a half wave is high 
impedance, the ladder line is used to get a match.  If you only have a 
1/4 wave vertical you don't need any ladder line to feed it ... a single 
wire of the proper length as a counterpoise works fine.

73,
Dave  AB7E



On 10/20/2020 9:58 PM, maflukey at gmail.com wrote:
> You can also feed a 1/4 wave wire with the feed point grounded to one leg of a piece of 450 ohm window line and then short the bottom end of the window line at the appropriate length to make an elevated J-pole.   Leave the top of the other leg of the window line open.    Essentially unity gain, much like a vertical dipole, but easy enough to hoist up into tall trees.
>
> Matt
> KM5VI