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Re: Topband: Toploaded vertical - SWR

To: Roger D Johnson <n1rj@roadrunner.com>
Subject: Re: Topband: Toploaded vertical - SWR
From: Wes N7WS <wes_n7ws@triconet.org>
Date: Wed, 19 Sep 2018 18:38:09 -0700
List-post: <mailto:topband@contesting.com>
Me too. But I wasn't ready to present them yet. I'm away from home at the 
moment. 

Wes

Sent from my iPhone

> On Sep 19, 2018, at 6:04 PM, Roger D Johnson <n1rj@roadrunner.com> wrote:
> 
> I did a quick model in EZNEC and came up with very different values.
> 
> 73, Roger
> 
> 
>> On 9/19/2018 6:53 PM, Wes Stewart wrote:
>> I suspect your data.  For a 0.1 lambda vertical, the radiation resistance 
>> will be quite low particularly with sloping loading wires and with your 
>> radial system the ground loss will be high.  Additionally, I think the top 
>> loading is insufficient to achieve resonance.  Yet you seem to have it.  
>> Your feedpoint Z is 15 ohm which seems too low, yet your SWR curve is too 
>> broad.  Something just looks funny to me, but I've been wrong before.
>> Wes  N7WS
>>> On 9/18/2018 1:44 PM, Ashraf Chaabane wrote:
>>> Hi all,
>>> 
>>> I just finished setting up my vertical antenna for 160 in 3V8SF location. 
>>> It is 17m (55 ft) long with 2 top loading wires 12m each (40ft), angle to 
>>> vertical about 40 deg. I added 8 radials, 20m each (65ft).
>>> With no shunt matching, the SWR at antenna base is 3.2 and at radio side is 
>>> 2.8. Is there any way I can improve the SWR further?
>>> 
>>> Photos of the antenna along with SWR curve can be found here: 
>>> https://drive.google.com/drive/folders/1_3FsWZI3zdi56zz0LOiKNOmfgiWeN6yG?usp=sharing
>>>  
>>> 
>>> 73 Ash 3V8SS/KF5EYY
>>> www.kf5eyy.info
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