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Richard Clark
 
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Default hints for quasi-professional cage antenna anyone?

On 30 Oct 2003 00:56:28 -0800, (SpamLover) wrote:


Richard, your design seems to favor a lot of parallel wires, but the
big improvement in broadbanding seems to be going from 1 to 2-3 wires.
Does the model confirm that? I have no modeling SW - what do you use?

Also, everyone,

- any hints at to whether wire diameter matters? Commercial antennas
have EITHER lots of wires OR thick masts. Is that out of mechanical
or electrical considerations?

- what are the dimensions of typical HF multiwire monopoles in actual
use on ships?

and

- don't u thing a multiwire cage sloper looks ubercool too?? a real
neighbour-pleaser!


Hi Filippo,

More wires, smoother passband. Less wires, more mismatches. If you
want one thicker element rather than more wire, it will have to be
roughly the same diameter as the cage presented at my page. No free
lunches at the Maxwell Cafe.

The model is available at that page, you can find a restricted version
of EZNEC at (predictably):
http://www.eznec.com/
It won't allow you to do analysis for this model (unless you cut loose
the $89), but you can view the design and the particulars (like wire
size, length, distance above ground, etc.).

I have a photograph of a pre-WWII battleship sitting above my
workstation here. Within the field of view is a cage dipole end (from
the photographer's perspective of being above the after gun turret, it
is quite close with six wires at a diameter of at least 18 inches).

73's
Richard Clark, KB7QHC