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Old Oct 02, 2008, 10:18 PM
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effect of tx antenna gain on 2.4G systems

Hi, need to ask any expert on this subject. I have a corona JR 2.4g module that comes with a 5dbi gain antenna. I have on hand 2 antennas ,one a 4dbi and the other a 8dbi gain. I kinda prefer the 4dbi as it is full swivel and about the same length as the one found on futaba.
I read somewhere that a higher gain antenna gives better horizontal distance at the expense of sky distance i.e more suitable for surface use, wonder if that statement is true.
If I use the 8dbi antenna, would that give me greater range or would the 4dbi antenna give better sky range?
Thanks
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Old Oct 03, 2008, 01:15 AM
early retired & loving it
USA, AZ, Kingman
Joined Aug 2005
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Higher gain antennas are more directional.
If you take a circle and squeeze the sides it becomes far reaching in the longer direction and much shorter radiation at the sides. At higher gain you have to point the gained pattern toward the receiver.
Some higher gain antennas move the circle so it starts radiating just in front of the antenna and not behind.
You really have to look at the designed radiation pattern to see how it could affect communications.
And even that is just a theoretical radiation pattern.

http://en.wikipedia.org/wiki/Radiation_pattern

here are many designs and their patterns.
http://www.kyes.com/antenna/navy/rpatterns/radiapat.htm
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Old Oct 03, 2008, 07:45 PM
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Thanks for the info.Will give the 4dbi a test run and see how it performs.
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