Hello all...
I am in the process of putting together final plans for a 2 element
vertical - 1/8 wavelength spacing with delay lines of 159 degs and 193
degs as per spec shown in ON4UN Low Band DXing book (tnx tip TOad)...
Gain a little over 4 dB in a cardiod pattern (towards Europe, of
course). The verticals themselves would be Force 12 180BV - a shortened
vertical with a wire section drawn away from the midpoint of the
radiator to gain "length".
The verticals will be elevated, with elevated radials, I hope 8 is
enough for it to work well but could live with 16 per vertical. Three
questions I can think of coming to mind immediately are as follows:
1) Is it mandatory that the crossing radials from the two verticals be
married together when they cross? With only 1/8 w/l spacing of the
elements there will be a lot of these radials crossing one another. It
will be much easier to erect if I do not have to deal with that. I can
drape the loose radials away from the base of the vertical and
individually tension them against deserving trees and towers.
2) I am going to raise the base of the verticals - but by how much?
The verticals will be mounted on short towers... question I see is would
I gain anything by their elevation? I am guessing that with a straight
section of tower stuck in the ground and a pointy top section the base
of the vertical would be roughly 15 foot above the ground. I could add
tower sections to increase the elements height above ground to 25 or
even 35 foot relatively easily but am I going to gain anything?
3) I think the 15 foot number is about minimum, and working on the
antenna should be fairly easy. If I go higher the radials will develop
a "pitch" downhill from the verticals' bases... essential forming upside
down cones.
Thanks for your input - Summer is here (not that is much needed here in
Florida) but Summer to me always mean antenna projects to try out in the
Fall!
73,
Jim, K4OJ
bcc: Ink, Dan
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