[Elecraft] cobweb antenna

[dombaines at yahoo.com]

Jim,

Thanks for the links interesting...

This is the Elecraft list so yes my KX3 with internal ATU and another 
without and T1 ATU finds a match easily, same for K1 or K2 with this 
antenna.

You do not have to buy the antenna at all ... you can build your own 
from a few parts as I did. A stanchion floor plate (so it fits on top of 
the mast), an Aluminium centre plate, some U bolts, lengths of hose pipe 
to fit over 4 poles so you do not crush them in the u blots, a couple 
dozen tie-wraps (for the wires) and some speaker wire (or zip cord) and 
a 8 turn RG213 choke at the feed point was all that was needed. I am 
sure the website links have all the homebrew info. You can buy a 
commercial version obviously as well.

If you do not have a lot of horizontal space (or an attic for all those 
stealth antennas) which is why is was designed, it works fine and it can 
be put up and brought down pretty quickly especially if you have a 
restriction on permanent antennas. If you are so inclined you could 
create pivots on the poles so the antenna would close up on itself a bit 
like a rotary washing line? I used fishing poles so mine basically came 
apart easily after use.

No mystery about the design either it is basically a set of nested 1/2 
wave dipoles in a halo's in a square all fed from a common feedpoint. 
One side is approximately 1/4 of the size of the lowest frequency you 
want to use. You got a small apartment, back garden or 'yard' in US and 
it can mean getting on air. It is a 'balanced antenna' so that means no 
radials etc..

Oddly enough mine worked fine (20ft TV pole) on 160m and 472KHz/500KHz 
with a few modifications... first I slid a section of PVC between the 
pole and the H&K wall brackets so the pole was better insulated, then I 
jumpered both the upper feed points to the pole from the connector box 
(just a series of chocolate blocks for the wires) at the top then fed 
the pole from the bottom against ground. The antenna then acted as a 
short vertical with a big capacitance hat.

72

Dom
M1KTA

On 31/05/13 17:55, Jim Brown wrote:
> On 5/30/2013 7:27 PM, Bill Blomgren wrote:
>>
>> Has anyone tried one of these critters, and if so, is the Elecraft 
>> happy with it?
>
> Why BUY an antenna when you can  very easily build one for a lot less 
> money that will likely work better?  Here are some articles by hams 
> who have done a lot with only a little bit of space. The first is by 
> AC0C, who built a complete antenna system in the attic of his apartment!
>
> http://www.kcdxclub.com/Stealth%20Antennas-r1%20-%20AC0C%20-%202-2009.pdf
>
> 73, Jim K9YC