Modifying a 2 4 GHz Dipole Antenna to 5 GHz

In this video I convert a 2.4 GHz dipole antenna into a 5 GHz antenna. I needed quite a few 5 GHz antennas for a project I am working on and it was much cheaper to modify 2.4 GHz antennas.

5 GHz and 5.8GHz dipole antenna: http://youtu.be/ysHP_Yi8bx8

2.4 GHz dipole antenna: http://youtu.be/bs8hvXGJdhM

Comments

[anihver]

Firstly love your tuts, But could you explain why shortening the antenna changes it and how to know by how much to shorten it by? I am going to do this hack but I'd like to know the science behind it if it's at all possible to do a vid about the workings of the antenna and why you had to shorten the sleeve.
Keep up the good work. Cheers

[pallc]

You'll have to read up on antenna theory. Something to do with the wavelength in a certain unit like meters and the length of the antenna being a fraction of the wavelength... like a wavelength, 5/8, 1/2, 1/4 wavelength.

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

http://www.hamuniverse.com/hamantennalengths.html

There is an old device to measure wavelength of an emitter/transmitter that was called a lecher wire.

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

This device helped me visualize why. There is also something called a Standing Wave Ratio (SWR) Meter.

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

This goes further to help match up the impedence of the antenna to the receiver/transmitter. The ratio of 1:1 is desired so there are not losses to heat and you have maximum efficiency.

[anihver]

Also I'm wanting to use a patch cable with a fishbone yagi 16dbi on a galaxy s2, the aim to pickup 4G network that's signal is 1.5 kms away. Possible or should I use a different antenna? If possible at all. TIA

[Danger is my middle name]

Not my area of expertise at all, but very interesting!