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AG6CX

Joined: Sat, Apr 4th 1998, 00:00 Roles: N/A Moderates: N/A

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Off Center Fed Dipoles Feb 4th, 19:28 5 654 on 6/2/14

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Off Center Fed Dipoles AG6CX on 5/2/14
Thanks for your observations Zack.

I guess I have to read your Mar 2001 article QEX (Pg. 55)
Making Off-Center Fed Dipoles Work (RF). I remain perplexed that the article download is not available to members, but would appreciate a copy if you can spare one, or request TIS to scan and send to edwmccann@aol.com. Happy to pay whatever is needed.

In any event, my basic question remains unanswered and I can find no answer: If the OCF antenna is supposed to be resonant on even harmonics, why isn't such an OCF antenna cut for Fo = 3.55 MHz resonant on 6xFo = 21.3 MHz ? (We can worry about the impedance with a balun).

Odd harmonics are 3,5,7,9, etc. So the 40m dipole works on 3x7.0=21.6MHz, as has been known.

Even harmonics would be 2,4,6,8,10, 12, wouldn't they? So wouldn't one expect the OCF Dipole to be resonant at the 6th, 8th. 10th, and 12th harmonics? Or are the 6th, 10th, 14th harmonics not as"even" as we think, being twice the 3rd, 5th, and 7th harmonics?

I look forward to your article to shed some more light on the matter.

73
AG6CX


Off Center Fed Dipoles AG6CX on 5/2/14
Thanks for your observations Zack.

I guess I have to read your Mar 2001 article QEX (Pg. 55)
Making Off-Center Fed Dipoles Work (RF). I remain perplexed that the article download is not available to members, but would appreciate a copy if you can spare one, or request TIS to scan and send to edwmccann@aol.com. Happy to pay whatever is needed.

In any event, my basic question remains unanswered and I can find no answer: If the OCF antenna is supposed to be resonant on even harmonics, why isn't such an OCF antenna cut for Fo = 3.55 MHz resonant on 6xFo = 21.3 MHz ? (We can worry about the impedance with a balun).

Odd harmonics are 3,5,7,9, etc. So the 40m dipole works on 3x7.0=21.6MHz, as has been known.

Even harmonics would be 2,4,6,8,10, 12, wouldn't they? So wouldn't one expect the OCF Dipole to be resonant at the 6th, 8th. 10th, and 12th harmonics? Or are the 6th, 10th, 14th harmonics not as"even" as we think, being twice the 3rd, 5th, and 7th harmonics?

I look forward to your article to shed some more light on the matter.

73
AG6CX


Off Center Fed Dipoles AG6CX on 4/2/14
Various sources state the OCF Dipole is resonant at Fo, 2xFo, 4xFo, 8xFo. Others sources say it is resonant at even harmonics. Sources also say the CF Dipole is resonant at Fo, 3xFo, 7xFo.

We know that a CF dipole cut for 7.0MHz will resonate at 21.0MHz.

But for the OCF Dipole with Fo = 3.55MHz, the literature says that resonance will be at 3.55. 7.10, 14.2, and 28.4 MHz. If the OCF Dipole is supposed to be resonant at even harmonics. why don't these antennas work at 6xFo, which for Fo=3.55 MHz would be 21.3 MHz. Isn't a sixth harmonic an even harmonic?

What am I missing?

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