View Full Version : Alpha Delta DXCC vs. Buckmaster OCF Dipole
N7TML
09-27-2007, 01:31 PM
Well my visions of a tower and beam at the new home were just that, a vision. So now I'm looking at other antenna options. Since I got my license over 40 years ago I've never use a dipole or any of its variations. Now it looks like a wire antenna will be my only antenna for a while. I have room for a dipole up to 200' long but it would not be an easy route for coax from the shack. So I'm thinking about a multiband inverted V. Seems that making one shouldn't be too difficult but have been looking at two manufactured ones. So my questions: is there any real performance differance between a center fed and an off center fed dipole in an inverted V configuration? Are inverted V's directional and will I need to put up two to get good directional coverage?
Thanks, Tom, N7TML
wc5cw
09-28-2007, 02:27 PM
Tom, (et al)...
An abreviated answer:
First of all, build your own wire antenna...Hell, that's almost a given for the enjoyment and the satisfaction of "having done it myself" credit...Save some bucks, as well.
Second, an Inverted-V has many of the radiation properties of a flat-top dipole...Both are subject to radiation patterns and take-off angles highly influenced by the height above ground with reference to the wavelength of operation...Generally speaking, since most of the radiated energy of a dipole and an Inverted-V (or an OCF doublet) happens within the center 1/3 of the radiating wire, the height of the flat-top dipole and the center support height of the Inverted-V will determine the radiation pattern and take-off angle as mentioned...The theoretical "golden number" for the text-book broadside "figure 8" pattern occurs at a 1/2-wavelength above ground (for the lowest frequency you are operating at)...Anything lower to the ground and the antenna becomes more uni-directional and the take-off angle rises toward the vertical axis.
Other considerations are feedline type (coax, balanced wire, balun use, etc., etc.), materials and details of feedline routing, grounding and lightning protection.
That's the short answer...You may want to get a copy of the ARRL Antenna Handbook...Any edition that's available--even those that are 30 years or more old--will show you the different characteristics of a flat-top and Inverted-V dipole for the variables including the height above ground -vs.- wavelength of operation variables.
Good luck.
FWIW
Bruce
WC5CW
Try building a doublet, it's a pretty good antenna and cheap to build.
GOOD MORINIG
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