GadGetZzz

i am studying wireless newtworking and the questions is "define bandwidth of an antenna. if the elements on a yagi antenna have their diamater increased - what effect does this have on the bandwidth?"

The bandwidth will be increased proportionally to the square root of the diameter.

2008-10-14 23:10:29 by maxim

Diana Eng demonstrates and explains a Yagi antenna, useful for transmitting directional signals. blog.makezine.com

Assuming clear line of sight, and the AP/router is using a 3dbi omnidirectional antenna.

You ought to be able to get a couple of miles out of it if the yagi is aimed carefully.

With carefully aimed parabolics and wave guides instead of coax at both ends, I've managed 22 miles. One link has been running for over 4 years now.

2009-03-19 10:19:18 by luckyman

Mounts to any pipe or antenna mast 1" to 1.5" diameter
Includes Vertical and Horizontal Polarity Mounting
Extends Wireless LAN from building to building

I have a world space reciver which comes with a patch antenna. As the patch antenna is very fragile I am not able to install the same outdoor.
Can any one suggest a design for Yagi antenna which can recive Frequency Range: L Band (1453.384 - 1490.644 MHz), along with a simple design of Low Noise Amplifier.

I am planning to make this at home so please let me know the design as simple as possible.

http://www.alibaba.com/memberhome/fm/fmProductDetail.htm?productid=11062100&printFlag=true

2006-01-31 20:52:08 by hcl_ind

U-bolt Mast Mounted
Neutral Color
"L" Bracket for 45° Angled Tilt Adjustments

Please get back to me.

Here dude http://www.ac6v.com/antprojects.htm This has a list of antenna projects you can do. Hope it helps!

2006-04-27 19:22:23 by ghettoskater911

like those routers on ebay that you can get with a yagi antenna and they say you can pick up wifi from 10 miles a way

the router is a T-Mobile/Linksys WRTU54G

What they forget to tell you is that the wifi source has to be LINE OF SITE! If your source is an indoor router that is 10 miles away, you will never see it at all even on flat terrain. Yes Wifi can work at long distances BUT the source and the receiver have to have outdoor high gain directional antennas (aimed at each other) and the radio path has to be line of site - no obstructions!

The record for wifi distance at present is 237miles.
Check this.http://www.engadget.com/2007/06/19/venezuelans-set-new-wifi-distance-record-237-miles/

But a Yagi on your router isn't going to work that way unless there is another yagi pointed back at you from the other end and nothing is blocking them! In areas where there are lots of wifi routers you won't get very far at all because of all the interference.

The other thing they forget to tell you is your Linksys home router is about 30-50mw of output and the ones used for long distance are 250 or 500mw out! These specialized routers are designed for outdoor use as well.

2008-08-08 11:07:08 by william m

I want to send a full-wave rectified signal at 2.4 GHz, could a Yagi antenna be used to transmit such a non-sinusoidal waveform ?

My intended receiver is insensitive to sinusoidal waves, it is only sensitive to rectified waves.

Looking at your various questions, it appears that you are trying to figure out how to transmit square pulses.

As other posters have noted, a square pulse is the sum of an infinite Fourier series containing the fundamental frequency and every other harmonic. But since all real systems are band-limited, this is impossible in real-life.

An adequate representation of a square wave can be created with three to nine harmonics. Check this link, a little over half way down there is an applet which allows you to view a square wave recreated from limited number of harmonics.

http://www.jhu.edu/~signals/phasorlecture2/indexphasorlect2.htm

If you have a bandlimited system, then you cannot transmit a perfect square pulse. You can, however, recreate the pulse using digital methods on the receiving end. Check page 3 of this presentation for the concept:

http://www.freedomuniversity.net/ColoradoTechUniv/EE645/LessonNotes/2006/Lesson1/Chapter1web.pdf

So, possible approach, using your band-limited system, transmit the best representation of the square pulse possible. At the receiving end, typically you would use a matched filter and integrate the received signal over the sampling frequency. The output is then compared to a threshold to determine if 0 or 1 is transmitted. Based on this, you can recreate your square wave.

Hope this helps.

2006-02-19 18:46:08 by Neurofractal