[Antennas] New OCF Dipole

Wed Mar 12 07:26:13 EST 2008

A week or so ago I saw a posting here regarding an OCF Dipole. I started
digging into the links, and finally built one based on the plans in the
ARRL Antenna book. I made a 4:1 balun on a T200-2 toroid and measured out
the legs per the book. Hoisted it up on a temporary mast (poor thing looks
really cobbed together) with a feedpoint height of about 15ft. The ends at
about 8ft. Right off the bat I had a match on the even harmonics (I just
realized I haven't checked the odd harmonics yet). But it was high on 75m.
Well, it was 2:1, but my radio, IC-735, recommends not transmitting into
more than a 1.5:1 for some reason. It was much better at the low end of
80m. I twisted some 1kV caps together to make about 250pf total and put it
in series with the long leg. Brought my 1.5:1 point up to about 3900kHz.
So, next step is more capacitance to give me all 80m/75m. From the reports
I got last night, This should be a good performer once I get it up to
working height, about 35ft center, 10 ft ends. Of course, this was on 75m,
so it might not be as good if it goes up higher.
I'm a new ham and went straight into general. I'm having a blast. Who
would have thought you could just apply some theory and actually get
results?! And I'm learning alot in the process.
Thanks to everybody out there. This is a great resource.
Bill KC2SUO