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  #17  
Old 03-13-2012, 01:35 PM
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Originally Posted by hammer0630 View Post
Damn, I wish I could understand this graph. It looks like some one transmitting at the North Pole and the signal is being sent east against it's will.
That graph is not a radiation plot of a vertical antenna; looks like the plot of a Yagi beam to me.

First of all, let's understand that each color is the antenna radiating at a different height above ground.
30, 35, and 40 ft - respectively.

Look at this radiation plot as if you were standing and looking at a Yagi beam antenna pointed twards the East, and you are South of that beam antenna. Those two larger lobes are the angles of radiation relative to the horizon. There are two main lobes, and these will both 'shoot' RF radiation twards the ionosphere at those same two different angles. The longer lobe is 15 degrees to the horizon and stronger, and the shorter lobe isn't quite as strong and is approximately 45 degrees to the horizon. The longer lobe is at a lower angle and throws the radiation potentially farther.

When you were a kid and threw small, flat stones across a pond - you had to throw them at a low angle at that pond if you wanted that rock to skip across the pond as many times as it could. Perhaps a poor analogy; but fair enough . . .
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Last edited by Robb; 03-13-2012 at 04:23 PM.

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  #18  
Old 03-13-2012, 04:19 PM
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Originally Posted by BammBamm View Post
I am curious I have a I-max on 2 10' fence poles mounted at 20' to base of antenna. I am moving to a new home and plan to construct the same antenna setup but place the bottom of the mast on my back porch roof and secure it to the peak of the home and where ever else needed to secure it. My porch roof is at 23' and the peak of the house is at 46' so after finding this out I want another 10' pole added to put the base of the I-max at 53' above ground and the mast would only be 7' above the peak of the roof. I see no reason that this is a problem but was wondering how much of an improvement will I see over my setup now at 20' compared to 53'? I know it will be better but by how much? My S-2016 folded over a few days ago in the wind so my I-max is back and seems to be the only antenna able to take the windy city short of $250+.
In my experience with vertical CB antennas I was amazed at the difference when raising the base of my antenna above the roof peak, and it was even better in the direction of the house.

I don't recommend installing CB antennas on the house, but getting it above the peak should show you a really nice increase in local performance, in addition to the increase in height.
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  #19  
Old 03-13-2012, 08:58 PM
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Wow I'm amazed at the responses I've received and I like the one of do it and let us know. I will as soon as my move is complete. First it's furniture and beds and clothes then I get to put my radio back together. These are the wifes rules as I must go mobile for a while until the house is setup. My entire base is now down and boxed up awaiting movement to new home. I should have it up within 2 weeks or less and will post the outcome. Thanks to all.
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