[TowerTalk] 80m DX special dipole

[Guido Tedeschi]

22.5 pF per foot


Il 11/09/2018 22:41, Jim W7RY ha scritto:
> Sent from my wireless communicator
>
> On Tue, Sep 11, 2018, 3:36 PM Jim W7RY <jimw7ry at gmail.com> wrote:
>
>> What about capacitance per foot?
>>
>>
>> 73
>> Jim w7ry
>>
>>
>>
>> Sent from my wireless communicator
>>
>> On Tue, Sep 11, 2018, 2:27 PM Guido Tedeschi <guidoted at gmail.com> wrote:
>>
>>> I built an 80m DX special dipole.
>>>
>>>
>>> http://1vc.typepad.com/ethergeist/2011/01/a-broadband-contest-antenna-for-80m.html
>>>
>>> I used the Messi & Paoloni BROAD-PRO 50/C cable instead of RG213
>>> (https://messi.it/dati/immagini/BROAD-PRO50-All6_EN.pdf).
>>>
>>> The cable lenghts are recalculated for a velocity factor of 0.85 instead
>>> of 0.66 and the overall lenght (cables plus wires) is the same of the
>>> original project, but the result is not satisfactory.
>>>
>>> The SWR pattern is correct but it is like having an offset of about 2:
>>> the two lower dips have an SWR of about 2 and the highest SWR on band
>>> reach 3
>>>
>>> What could be wrong?
>>>
>>> Is it necessary to use a cable with 0.66 velocity factor?
>>>
>>> Thanks and 73
>>>
>>> Guido, ik2bcp
>>>
>>>
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