OCFD improved?

[KX4QC]

My main HF antenna has been a 160m stranded 10G half-wave off-center 20% fed dipole at 90 feet between high pine trees. The 6:1 balun with common mode choke gives a clean signal to the remote AH-730 tuner. (Yes, the design looks a bit like a heavy-duty big B*ckm*ster.)

So what's not to like? It's landed a few DX awards, though i notice that, as expected from its huge length, it works a bit better on lower rather than higher frequency bands. So as any ham at Solar Max, I can't leave well enough alone, so I decided to add a second pair of elements, still for a 20% feedpoint but cut for half-wave 20m. So now it's a kind of offset fan dipole.

Does it tune? Yes. Is it any better? Maybe some, but watch this space for details, as I suspect it will be more improved on some bands than others. EZnec suggests a more useful polar diagram for it, but let's see....

While I was constructing it, a mischievous thought occurred: what would happen if the long and short arms of the second element pair were reversed, so that there would be one long arm each side of the balun, and one short? My guess is that it would be harder to match, but has anyone actually tried it?

[KW4CQ]

Jon, during my first ten years at this QTH I managed to work over 300 DXCC countries with my OCFD at 50 feet. I took it down two years ago to try the "W5GI Mystery Antenna". Good on 20m and above, in fact it is reported to have a 6 dB gain on 20m. Nevertheless, I plan on replacing it with my old OCFD in the near future in order to chase some of the upcoming DXpeditions on the lower bands.
Regarding you idea on "improvements to the OCFD", If I can find and resurect my EZNEC software I will see what it might look like.
Catch ou on the DDXG 75m net.
73, Bob KW4CQ

[admin]

Aw...
The fan OCFD is an improvement by all of about 2dB!
-Not much that you'd notice, but it does seem to change the radiation pattern a little to the good.
So it stays for now.

Is it worth copying? Maybe, but remember that the 2-element version works well, and is nearly as good as the 4, and a it's simpler.