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Old 04-26-2005 | 03:46 PM
  #753  
howard hudson's Avatar
howard hudson
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Joined: Nov 2002
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From: some damned place called Iowa
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Originally posted by Boomer
Guys - just cut the wire to 3.6" and be done with it.

This is a topic that has been discussed on the ARL boards for forever. ARL, for those who don't know, is the amateur radio body. If anyone around here would know more than they about practical usage of radio, antenna, etc. I'd like to know who it is.

The crimps, the coils, etc. are there to reduce the physical length of the actuall antenna assembly, not the length of the antenna WIRE.

Let's look at another from hyperlinktech, shall we?


From this, you'd think that the little coil in there is to increase signal strength, etc.

Until you look at the physical size of the antenna. This is a 6" antenna as compared to 10" for the one with the dual crimps. Basically, there is about 4" of antenna that is coiled up to shrink it's length from around 10-11" down to 6".

A longer antenna (lower harmonic) for this is going to be 21" (used for higher gain antenna or marine or places where length doesn't matter so much) - and you can see THOSE there too.

{{sigh}}

This is basic EMF theory. The length of the antenna wire must coincide with a harmonic of the wavelength of the signal in order to get optimal reception. It's as simple as that.

for a 2.4GHz frequency, the wavelength is just over 4" (thus the length of the antenna being 8" is 2x the wavelength which is normal). You could likely use 4.whatever (full wave) and would work great. However, why do that when you can use the 3.6" and be just as good.

the 3.6" antenna length is the 3/4 wave harmonic and is one of the ideal lengths.

Please note - I used a straight 2.4GHz for calculations - I did not get the exact frequencies within that range so numbers are somewhat approximate.
WOW !! didnt expect all this just trying to help a guy out All I know is that what I did looks clean and I dont glitch bottom line. The track I run at is 120 feet by 80 feet. not flying a plane so as long as i have no glitches in that area Iam a happy camper ( oh ya and dont have to worry bout crystals anymore )
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