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Re: Less Than Perfect Antennas

Posted by David Gilbert on Dec 08, 2018; 7:01pm
URL: http://elecraft.85.s1.nabble.com/Re-Less-Than-Perfect-Antennas-tp7646930p7646956.html


The EZNEC+ model I did showed the same thing ... the two lower wires had
to be much longer than I expected in order to get even a moderate SWR. 
The pattern looked awful even when I did so.

73,
Dave   AB7E


On 12/8/2018 4:49 AM, Don Sanders wrote:

> While in Ecuador I tried this skeleton discone. Did not work well.
> Actually I had to extend the lower wires from formulas by about 30 %
> to get a low <3 swr at design freq, 40 meters. I did not try adding more
> wires.
> I had several good antennas I made so I did not do further investigations.
> Dr. Don W4BWS
>
>
>
>
> On Fri, Dec 7, 2018 at 5:30 PM Charlie T <[hidden email]> wrote:
>
>> I wonder if anyone has ever tried, for want of a better name, a "Skeleton
>> Cone" which consists of a single horizontal wire connected to the coax
>> center conductor and two sloping wires at 45 degrees, in the same plane
>> connected to the coax shield.  A true Discone antenna would have many
>> (typically eight each) horizontal and sloping elements. I'm guessing many
>> of us have used the VHF/UHF version for very wide band coverage, for
>> example 144, 220, 432 MHz and even higher.  I know I have one up and it
>> performs as well as a regular single band  ¼λ ground plane (unity gain)
>> on all three bands with low SWR.  The ICOM version as well as a few others,
>> also have a loaded whip for 52 MHz mounted on the bushing that the
>> horizontal elements are screwed into.
>>
>> I'm also guessing the formulas for a true Discone would work for a
>> "skeleton" style as well.  I Since it is inherently a wide band design, the
>> actual lengths are probably not too critical.  I've heard this type antenna
>> described, but I don't remember where or how well it supposedly worked.  It
>> obviously requires two supports, high enough that the sloping wires ends
>> are off the ground by a bit.
>>
>> 73, Charlie k3ICH
>>
>>
>>
>>
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