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Author Topic: Off-Center Fed Dipole question  (Read 3983 times)
N9AOP
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« Reply #15 on: September 29, 2017, 10:38:10 AM »

I use a homebrew with the dimentions of 45/90 that is fed by ladderline to a 4:1 balun.  SWR is low except on 15 and 30 which is what you would expect.  The SWR compares favorably with a commercial unit.
Art
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WA3SKN
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« Reply #16 on: October 02, 2017, 09:16:58 AM »

Why do you prefer OCF?  Have you considered a regular dipole or loop?

-Mike.
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N4MQ
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« Reply #17 on: October 02, 2017, 02:54:46 PM »

OCF allows multibands, MY 160 windom ( not NC style) works up thru 15, never tried 10.  Much better than my fan dipole that was way heavy.Enjoy Woody
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W5DXP
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« Reply #18 on: October 02, 2017, 08:09:33 PM »

I use a homebrew with the dimensions of 45/90 that is fed by ladderline to a 4:1 balun.

What is the length of your ladder-line?
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N9AOP
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« Reply #19 on: October 03, 2017, 08:42:08 AM »

W5DXP,
You want to use an odd multiple of 1/8 wavelength at the lowest freq.  My lowest is 3.5 so the length is 94.8 ft.  Don't forget to figure in the VF of the line.  Usually .88 for 300 ohm and .91 for 450 ohm.  The math would be-- 123/f X VF. If you use any old length of ladder line you may find a frequency that causes your tuner to arc or refuse to tune.
Art
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W5DXP
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« Reply #20 on: October 03, 2017, 10:10:37 AM »

If you use any old length of ladder line you may find a frequency that causes your tuner to arc or refuse to tune.

And/or you may encourage common mode signals. The following is for an 80m OCFD vs CFD with a ladder line length of 65 ft. (1/4WL).

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