We're talking about making a switching directive array out of GUY WIRES.
That's a lot of work. So, what is the benefit. That's the analysis.
A pair of inverted "V"s at right angles will be very simple and manageable.
Much easier than
feeding the guy wires. Now that gets into the ballpark of a tradeoff.
But, at 70 feet, they will have nearly equal performance. The 4-6 dB is
only at the 30 degree
takeoff. At higher angles, the front to side drops way off to near
omnidirectional.
What we are talking about is not the same thing as stacking beams to get 2-3
dB. Beams
have 20-30 dB of front to back as well as 6-8 + dB forward gain. Stacking
goals
maintain the 20-30 dB front to back and improve the forward gain to 8 - 10 +
dB. So,
replacing them with dipoles would not be useful, not to mention that
rotating the
dipole would be ackward.
An inverted V has 0 dB front to back and only 4-6 dB front to side at 70
feet.
That front to side is at the null. It decreases over a 120 degree sector.
BTW,
at 140 feet that same inverted V has 15+ dB of front to side. Now you would
need to
have multiple inverted Vs, else you couldn't work the stations in the null
through a pileup.
I agree with Tom's last paragraph. 80M inverted Vs just begin to play at 90
feet.
That's why I recommended what I did.
Bill, N3RR
>
> So, would you be willing to throw away 4-6 dB gain on the highbands?
>
> Given your same conclusion, you could replace all your Yagi's
> with simple DIPOLES.
>
> Yes, a dipole is a GOOD antenna, but some people go to LOTS
> of expense and effort, i.e. stacks, to pick up 2 to 3 dB gain.
>
> FWIW, I've worked over 320 countries on 80, 40, 30, 17, and 12M
> using only Dipole antennas, plus a single vertical on 80.
>
> Bottom Line: For SERIOUS DXing, it may be useful to have a
> PAIR of 80M inverted vees at right angles to each other, even
> at 70ft. My experience with 80M inverted vee's is that they really
> start to 'play' at 90 ft and higher.
>
> de Tom N4KG
>
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