The vertical antenna literature recommends loading a short vertical,
efficiency worst to best as bottom coil, center coil, capacity hat.
More top capacitance needs less coil inductance if both are used. My 80m
vertical is 3' irrigation pipe by 40' with a 12' diameter hat of 6 x
3/8" Al tubing and 11ga Al perimeter wire, no coils. I'm very pleased
with the performance, and bandwidth and feed impedance.
Try some designs in EZNEC, and you will see the tradeoffs.
Grant KZ1W
AA6DX - Mark wrote:
> Me too ... would like to know .. I have the data for doing the modification
> hanging on my bulletin board, but have not "got around tu it" Mark AA6DX
> K6H (CQP, NCCC)
>
>
> ----- Original Message -----
> From: "Anthony Wanschura" <ajwanschura@gmail.com>
> To: <towertalk@contesting.com>
> Sent: Sunday, September 19, 2010 5:21 PM
> Subject: [TowerTalk] "Top loading" of HF2-V vertical
>
>
>
>> For those who have done it, I have a question about "top loading" of the
>> HF2-V vertical (as described in the HF2-V manual).
>>
>> I know that this modification will raise the radiation resistance and
>> increase the bandwidth of the HF2-V, but does anyone feel that the
>> top-loaded antenna actually "gets out" better on 80 meters? Tell me your
>> experiences.
>>
>> Thanks,
>> Tony KM0O
>>
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