[Elecraft] Strange Vertical - need help

[Joe Subich, W4TV]

The Zero-Five web site specifies 100 feet of feedline and a "wide range
antenna tuner" for that antenna.  The SWR readings you report are about
what I would expect for an untuned antenna of its type.

The Zero-Five GP40-10 is essentially a 20 meter half wave (26 feet
vertical, 8.25 feet horizontal) fed 25% from one end ... a classic
OCF design.  The claims of operation on 40 (and 30 meters) bother me
since the antenna is far too short for effective 40 meter operation.
I suspect the feedline is part of the antenna on 40 meters.

Since the antenna manufacturer specifies a minimum feedline length
of 100 feet, they're obviously using the feedline to moderate the
native feed impedance so the tuner can handle it.

73,

    ... Joe, W4TV


On 3/11/2012 11:48 AM, KC6CNN wrote:
> I installed a vertical with ground radial kit up 20 feet.
> The antenna mast and negative sheild connector is grounded to a ground rod.
> The antenna covers 10 to 40 meters.
> I can tune 10 meters fine, and fourty meters fine, but 12,15,17,20,and 30
> will not tune and SWR are high.
> here are the SWR reading taken on AM running 25 watts.
>
> 10 meter
>
> 2804550 is 2 to 1 SWR
>
> 2882000 is 1.5  to 1 SWR
>
>
> 12 meter
>
> 2490000 is 3 to 1 SWR
>
> 24990 is 3 to 1 SWR
>
>
> 15 meter
>
> 2103900 is 4 to 1 SWR
>
> top porting is 3 to 1 SWR
>
>
> 17 meter
>
> 1809000 is 3 to 1 SWR
>
> 1817000 is 2 to 1 SWR
>
>
> 20 meter
>
> 1402800 is 2 to 1 SWR
>
> 1430000 is 2 to 1 SWR
>
>
> 30 meter
>
> 1010500 is 4 to 1 SWR
>
> 1014000 is 4 to 1 SWR
>
>
> 40 meter
>
> 7026 is 2 to 1 SWR
>
> 7290 is 1.5 to 1 SWR
>
> Any help or suggestions would be greatly appreciated. I will be receiving my
> K3 on Tuesday and am trying to get this antenna sorted out before then.
> Oh yea the rig I'm using right now is a Kenwood 570, the Coax is LMR400 with
> a 100' run. the Antenna is a ZeroFive GP10-40.
>
> Thank you
> Gerald Manthey
> KC6CNN
>
>
> --
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