Need Explanation of Antenna Dimension with Repect to Frequency

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ramesh21

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how to calculate the antenna height or length respect to frequency which we generate.....?
 
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First of all antenna height is independent of frequency .antenna height must be at least greater than 1/4 (wave length) being used
 

From your operating frequency, work out the wave length ( Wl = 300,000,000/F, F in Hz, W in metres). Then you can build your antenna using the Wl you have just calculated. Every Ant has a different charecteristic, basically the more work involved the better it is. The simplest ant. is a vertical piece of wire Wl/4 long. If you put a top horizontal section, this "tunes" the aerial down in frequency (it looks longer then it is) so this is what people used for AM reception because they could not get a 75 meter vertical wire up!!!
Frank
 

To add to the replies already posted, the type of antenna is a function of whether it is for HF, VHF/UHF or SHF etc. You wouldn't use a parabolic reflector antenna and feedhorn at 10MHz, just as you're unlikely to use an end-fed beverage at 22GHz.

If you want to start to gather info on antennas, I recommend a look at

**broken link removed**

As people have said, you need to define the wavelength of operation. If you make a quarter-wave vertical, it needs to live at the centre of a groundplane whose dimensions ought to be a wavelength in each direction from the bottom of the vertical element. You might be able to make a dipole in which case the total length is very nearly half a wavelength; the coaxial cable braid goes to one vertical element with the inner going to the other.

I suggest a read of the URL I provided and come back if you have more questions.
 

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