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Electronics => Electronics => Topic started by: airman00 on March 10, 2009, 07:42:02 AM

Title: Coiled Antenna and Straight Antenna
Post by: airman00 on March 10, 2009, 07:42:02 AM

I'm playing around with really low frequency radio and it seems like I need really long antennas.
Is there any difference in transmission between coiled antennas and straight antennas?
(http://[url=http://www.huagui.com.cn/images/RAC422.JPG]http://www.huagui.com.cn/images/RAC422.JPG[/url])
(http://www.lprs.co.uk/images/SSL21450%202.4Ghz%20antenna.jpg)

Meaning, lets say my antenna length is supposed to be 5 feet. Instead of having a 5 foot antenna standing straight up, I want to have 5 feet of wire getting looped around( to save space).

Title: Re: Coiled Antenna and Straight Antenna
Post by: paulstreats on March 10, 2009, 07:57:31 AM

Shortening an antenna always produces inefficiencies wether it be base loading, top loading, middle loading or continuous loading. - reductions in bandwidth, impedance and efficiency.

The best of the 4 types of shorter aerials is the continuous loaded coil. (the coil is wound up the entire length of the antenna. as opposed to a base loaded where there is 1 big coil at the base of the antenna with a small amount sticking out)/

Loading Antennas:

http://www.w8ji.com/mobile_and_loaded_antenna.htm (http://www.w8ji.com/mobile_and_loaded_antenna.htm)


Antenna Basics:

http://www.signalengineering.com/ultimate/antenna_basics.html (http://www.signalengineering.com/ultimate/antenna_basics.html)

follow on to coax basics and then to mobile antennas