[TowerTalk] Cob Web Antenna

[Joe Subich, W4TV]

 > What happens when such an antenna is mounted vertically?

You lose the "ground gain" ... it becomes a vertical dipole but
with nulls "broadside".

> Most of the Cobweb style antennas I have seen stop at 20m yet they
> would seem an ideal way to get reasonable size antennas on 30/40m, I
> don't consider a full size 20m quad loop overly big. What's the
> catch?
The difficulty of creating a sufficiently "strong" spreader assembly
to support the weight (particularly of the balun box) and the narrow
SWR.  Assuming the same percentage bandwidth as on 20 meters, a 40 meter
element will have < 50 KHz of usable bandwidth without a tuner of some
kind.  With high power and high SWR, I would be concerned for the balun
(matching transformer).

73,

    ... Joe, W4TV


On 10/30/2017 2:29 AM, Martin Sole wrote:
> I think the Cobweb(b) antenna is an excellent antenna for limited space 
> with usefulness as a second antenna for those with a bit more space. 
> I've seen a lot of discussion about its use in the horizontal plane from 
> 20m-6m. I have a couple of questions that might have simple answers.
> 
> What happens when such an antenna is mounted vertically?
> 
> Assuming vertical mounting is not massively detrimental, what happens 
> when a second passive element of similar shape is added at a distance, 
> ala 2 element yagi/quad?
> 
> Most of the Cobweb style antennas I have seen stop at 20m yet they would 
> seem an ideal way to get reasonable size antennas on 30/40m, I don't 
> consider a full size 20m quad loop overly big. What's the catch?
> 
> Martin, HS0ZED
> 
> 
> 
> 
> On 29/10/2017 10:13, Dan Maguire wrote:
>> KK0SD wrote:
>>>>> Has anyone actually modeled a Cob Web antenna?
>> More than you can shake a stick at.  See
>>
>> http://ac6la.com/aecollection9.html
>>
>> Dan, AC6LA
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
> 
> _______________________________________________
> 
> 
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>