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[Towertalk] Radial "fan out"/forking - MMANA model wanted

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Subject: [Towertalk] Radial "fan out"/forking - MMANA model wanted
From: (Pat Rundall)
Date: Thu, 28 Feb 2002 11:31:52 -0800 (PST)
For me at least, this remains in my mind as 
an "unsolved antenna mystery". A few have 
asked "why bother messing around with the 
forked radials idea - just put down 60 1/4 wl 
radials and get it over with?"  

In my case, I'm considering forked radials (at 
least, a minimal amount of wire and "stuff to 
duck under when mowing the lawn) for a Butternut 
vertical on a mast mount (at ~10' to 20' height) 
with the radials sloping to ground. 60 .25wl 
radials sloping to ground at ~30 degrees from a 
height of 15' turns a simple secondary antenna 
into a rather complex one. Assuming that 
because it is mast mounted and off the ground 
(the radials are somewhat elevated to begin 
with), perhaps a greatly reduced number of radials 
eminating from the mast would suffice.

I'd like to eventually model this, but the only 
modeling package that I have at the moment is 
the FREE one - MMANA (a fun free modeler - check 
out which 
probably isn't ideal for this sort of thing.

Once I get around to it, I'd like to model 
"standard forking"...
where A=B=C=D=(~.125 wl) and A slopes to ground
from 10' at the mast (M) at ~40 degrees.
            B /
      A     /   C
            D \

"multiband forking"...
where A=.125 wl on say 40m and ~.06 wl on 80m, 
B=.19wl on 80m (to finish the 1/4 wl), C=.125wl
on 40m, etc.

"upclose forking"...
where A is very close to the mast (a 45 degree
slope) and forks as soon as A hits the ground.

and finally "reverse forking"... 
I doubt this makes any sense at all.

       A/ \  
       /   \    
  C   /  D  \ 
      \     / 
       \   /
        \ /B

In fact, I have my doubts about quite a bit of 
this (especially the multiband forking - which
electrically needs a lot of work), but it should 
give me something to do while waiting for the 
ground to thaw to actually try this stuff.

Pat, N0HR

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