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KF9F Revives an
OCF Dual Feed Multiband Dipole
This multiband 160 thru 10 Meter antenna
design was adapted using the dual feedline
ALSO WORKS 160 WITH THAT DIMENSION
and old 73 Magazine Article published in 1984 by W4HDX**
Note that both ends of the
feedline are tied together and only grounded at the tuner
FEEDLINE LENTGH CALCULATION =
1.3 X WAVELENGTH / 4 FOR THE LOWEST FREQ.
Example - 3.9Mhz = 234 /
3.9 = 60 X 1.3 = 78'
I used a 3kw 4:1 air core balun
to match the 50 ohm feedline
going to the rollor inductor tuner.
The antenna loaded well on 160 - 10
You can use this handy center insulator and feed line
support by KF9F
or use your own design.
Overall installation of the OCF dipole at 34 feet apex in
inverted V fashion
Updated information from
Since I first tried
this antenna I have found two things.
works as well, if not better, using a choke balun (mine is 20 ft. of
RG 8 wound in a 1 Gal. Paint can) instead of the 4:1 balun as shown
in the original diagram
the Boy Scout J.O.T.A., I used the exact same setup as field day, only a
different location (remote as opposed to urban). Upon finishing
I tuned up on the W.A.R.C. bands, and again, with a roller inductor
transmatch, the thing loaded exceptionally on all freqs.
3: I mistakenly said to some of the guys here that RG
59 would be OK for 100 Watts or less, but that is presuming you use a
tuner and insure low VSWR before going to full 100 W. just to be
there was just a way to rotate
According to our research...
the article in February, 1984, 73
Magazine was originally written by J. W. Spencer, W4HDX, as printed in the
upper left portion of the article in that magazine.
There appears to
be some conflict with the author's call sign on other websites.
It has been reported (on other
websites) that the correct call sign is W4HDL, but this call sign is
registered with the FCC in another
name than the original author of the
article. According to our research, the correct call sign should be,
W4HDX. The author's name in the article and call sign do seem to
match on QRZ.COM. http://www.qrz.com/db/
The original article used the same dual coax
feedline technique but used 50 ohm coax and the antenna was a balanced antenna, (equal side lengths), not an off
center fed type like the above projects uses. KF9F is using the idea for
the W4HDL dual feeds and not the original balanced antenna in the project
We want to credit KF9F for reviving
this OCF antenna and W4HDX for his dual feed line idea
and for sharing it with us! NO PART OF THIS
ARTICLE MAY BE USED ON OTHER WEBSITES WITHOUT WRITTEN PERMISSION!
Richard, KF9F here.... richaz at
Further reading on the dual coax feeder
design can be seen on the KB0SK site here! Look on the right side of the
page....click on each image. They can be
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