[Antennas] Classic 20 meter Endfed Zepp

[Niel - W0VLZ]

For me I was most interested in getting the antenna to the point that 
the KX3 internal antenna tuner could take over and I wanted to get any 
counterpoise up in the air without RF in the "shack". My main concern 
was feedline loss.
> Based on my observations -
> - Some sort of tuner is required (built into my KX3)
> - Feedline loss is essentially same as coax
> - Allows flexible deployment (Vee, L, vertical, sloper)
> - No on-the-ground radial or counterpoise requirement
> - Light weight
> - Entire antenna system is off the ground
> - Usually requires only one support
> - Optimized for one band but usually can be tuned as a random length 
> end wire for other bands
As I understand it, radiating feedline distorts the antenna pattern but 
this is usually a don't care for temporary QRP-in-the-Park sort of 
operating. The 1/4 wavelength of feedline gets things close enough that 
the KX3 internal tuner works with no problem. Single band / 20 mtr 
operation is a limitation but I typically schedule my QRP time during 
the day so I'm usually OK with that also.

No solution works best for everyone but this one happens to fit my 
operating habits fairly well.

73,
Niel - W0VLZ

Richard (Rick) Karlquist wrote:
>
>
> On 12/9/2016 7:06 AM, Niel - W0VLZ wrote:
>> Does anyone else tried a 20 meter End Fed Half Wave wire fed with a 1/4
>> wavelength of TV twinlead (Classic 20 meter Endfed Zepp)? I've used one
>
> The fundamental problem with this discussion is that it focuses
> on impedance matching, which it would do an OK job of, except
> that the line is being operated in an unbalanced mode and therefore
> will radiate AND will not do a proper impedance match.
> It would, in theory, work if you replaced the twin lead with 300 ohm 
> coax, which alas does not exist.  It would also work if you could
> put common mode chokes are both ends, but they are impractical for
> such a high impedance.
>
> The antenna will still radiate if you have a tuner that can tune it.
> But it may be nowhere near 50 ohms.
>
> It is fairly easy to match a 1/2 wave using around 2 uH and around
> 5O pF in an LC match.
>
> Rick N6RK
>