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Author Topic: Portable vs. Mobile  (Read 4949 times)
K0BG
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« Reply #15 on: November 26, 2010, 01:25:01 PM »

While I might agree that under some circumstances, if you're into repeaters like those in Colorado, a good old 1/4 wave work very well. It is the HAAT differential in this case. This said, I still be believe the information presented by Dan, is valid.

And Lon! Don't feel badly. As I said, it is a very common mistake. One could argue that there is low angle radiation, because there is if the antenna has an adequate ground plane under it. However, as I pointed out, the angle where the maximum energy point is, doesn't change much. I've seen figures from 24° to 29°, but 27° is where EZNEC says it is.

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W7HDW
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« Reply #16 on: November 26, 2010, 01:38:47 PM »

This is likely a dumb question but, do radials on a vertical antenna have an effect on the received signal and, if so, how much?
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K0BG
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« Reply #17 on: November 26, 2010, 02:02:12 PM »

Actually they do. when there is high ground loss, a lot of the power does nothing more than heat the ground under the antenna. And, high ground loss contributes to excessive common mode current.

As I alluded to, there is more energy at the lower angles when ground loss is low. Since antenna gain, or lack of it as the case may be, is reciprocal. So you, receive goes up too. However.... the given performance of an antenna between transmit and receive is not necessarily reciprocal. After all, we don't have control over the incoming wave's angle, or polarization. It takes a little thought to understand the difference.
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W3LK
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« Reply #18 on: November 26, 2010, 04:06:14 PM »

Alan:

I don't feel badly; just ignorant. Smiley
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