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Author Topic: Rubber duck antenna  (Read 370 times)
KB1ODE
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Posts: 2




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« on: January 25, 2007, 06:48:16 PM »

Any suggestions roe a replacement rubber duck antenna for a Yaesu vx 6r ht.  I am looking for something smaller that performs at least as well as the oem.  If not smaller, at least more flexible to make it more comfortable to carry.
Thanks
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KO1D
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Posts: 387




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« Reply #1 on: January 25, 2007, 07:22:43 PM »

I have 2 antennas for my VX7r. I got a maldol that covers 6, 2,440 and is about 7 or 8 inches long. Works pretty well. I also have a 2, 220, 440 antenna by diamond I think that works well also.

Dan S.
KO1D
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K0BG
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« Reply #2 on: January 26, 2007, 07:21:48 AM »

Size and efficiency are reciprocals.

Here is a rule of thumb; while not exact, it very close most of the time, if the antenna in question is resonant on the given frequency: Halving the length (say from 12 inches to 6), cuts the radiation resistance by a factor of 4, and reduces the efficiency by about the same factor.

Conversely, doubling its length increases the radiation resistance by 4.

There are other factors which enter in to this which makes the ROT inexact, it nonetheless exemplifies that size and efficiency are reciprocals.

Alan, KØBG
www.k0bg.com
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