[TowerTalk] vertical antennas math & 1/2 waves

[K7GCO@aol.com]

 In a message dated 11/4/01 4:40:12 PM Pacific Standard Time, K3BU@aol.com 
writes:<< 
  In a message dated 11/2/01 11:08:56 AM Eastern Standard Time, K3BU@aol.com 
  writes:
   >  aa4lr writes:
  >  >  Now, pi/2 wl divided by 50 is pi/100 -- which is 0.0314159..., and 
pi/2 
  >  >  wl divided by 60 is pi/120 -- which is 0.02618. Close, but not quite 
  >  >  0.025.
   >  Simple, 
  >  Tom is (always) right, you are using wrong Pi(e :-) 
  >       Yuri
  >  
  Actually it is a little less.
  Just to be more precise and not to accumulate errors while lying out 
radials 
  :-) 
  AA4LR example is valid for the length of the arc with radius of the radial 
  length, being .25 wavelength and that is 0.02618 wl.
  
  Proper formula for the straight distance A between the tips of the radials 
  (length R) and number of radials N is
  
  A = 2R sin 180deg/N
  
  so for 60 radials .25 wl. long
   A = 2 x 0.25 x sin 3deg
  A= 0.5  x 0.052335956
  A= 0.026167978 wl.
  
  For those who want to be precise, as they say, hope it helps.
   Yuri, K3BU >>
 
 Yuri:  I duplicated your figure  A=.026167978 WL by creating 2 "right 
triangles" with a line at 3 degrees bisecting the line bewteen the .25 WL 
tips (for further clarification).  Without a right triangle the sine factor 
is not correct.  Yuri I didn't know you were good on math also. hi  

Actually most all this radial math nonsence goes away with 1/2 wave 
verticals.  With the finances of the average DXer today, I cannot see why any 
DXer screws around with 1/4 waves.  A 1/2 wave is already resonant and 
doesn't need any more help in that department.  I've had great success with 
1/2 waves with just a ground rod to cool the coax shield feeding an L 
network.  How much E-field loss is there at the base without any radials?  
I'm not sure.  The higher the base of a 1/2 wave this problem reduces itself. 
 I will run a comparison with a side by side 1/2 waves--one with a ground rod 
and one over a good radial system.  WWVH has some radials out a ways.  I 
don't think they have to be a 1/4 wave although it sure can't hurt.  

Has anyone else any 1/2 wave vertical experience?  K7GCO 

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