Mike Walker wrote:
> To summerize the feed point is the middle of the of the slope and then the
> switching lines come back to the switchbox in the tower. Think of it as an
> inverted v that is rotated 90 degrees and the ends attached to the tower.
> The feed lines are 150 degrees ( 300\freq(mhz) * vf of cable * 150/360).
> We used RG8X mini foam with a VF of 78%. The switch box totally isolates
> the coax from the feedline (both ground and centre conductor).
I modeled something similar - I have four vees as you describe but I
first moved them 10' away from the tower (obviously top and bottom).
THen I modeled using 4 sources (i.e. the eqv of phasing I believe - I
have not figured out how to connect all together through transmission
lines using W7EL so I just used 4 sources and used phase angle). The
sources are at 135 for the two sideways vees and 270 for the back one.
This gives 9.3 dbi at 16 degrees when mounted at 105'!! This is 6db
better than a dipole at the same angle, almost 10db at 10 degrees and
more than this at 5 degrees!! THis is very impressive. The F/B is 30+
db! There are some side lobes that are down at -12 but this is ok as the
beamwidth for them is narrow. I tried using the 150 degrees you
suggested but the pattern got worse, gain went down, as did the F/B. I
need to figure out how not to have 4 sources but to add the effective
150 degrees you did (effective lengtening). I'll get there.
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