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Simple techniques for measuring Gain Antenna (WiFi)

Teknik Sederhana untuk mengukur Gain Antenna (WiFi)

Page / important information from the antenna homemade is the gain of the antenna, the higher the gain the better the antenna and its SWR is usually low. For those of you who are not able to make / buy SWR, may measure This antenna gain is the technique yan easiest and most inexpensive that you can use to justify the performance of your antenna.

How to measure the antenna gain is basically compares the received signal strength from our artificial antenna with a standard antenna we know his antenna gain. Usually the default antenna Access Point has a small gain of about 2.2-3dBi. We simply compare the signal received from the homemade antennas with a signal from the antenna 3dBi standard.

Preparation tool

  • Access Point with the standard antenna that can 3dBi off.
  • Pigtail known damping, usually with a cable pigtail LMR100 or LMR200 cable with a length of only 20-50cm has a small attenuation of 0.25dB.
  • Computers / Laptops with WiFi which has been installed for the site survey software such as NetStumbler (http://www.netstumbler.com).
  • Place the Access Point & Computers at a considerable distance, about 20-50 meters. In the guard so that no interference / reflection signal. Should be set so that within a distance of 1-2 meters from the signal straight line between the Access Point & Computers no interference at all.

Step measurement

  • Measure the signal on your laptop / computer from the Access Point uses the default antenna 3dBi. Set aside some time to obtain the most stable signal, for example, the received signal is X dBm.
  • Replace the default antenna 3dBi with our artificial antenna is connected using a known damping pigtail for example 0.25dB.
  • Measure the signal on your laptop / computer from the Access Point using homemade antennas. For example, the received signal is Y dBm.

Calculation of antenna gain

 Antenna Gain (dBi) = | Y - X | + 3dBi + 0.25dB 



Where:

 X = signal received from a standard antenna. Y = signal received from antenna to be measured. 



0.25dB is attenuation pigtail, was 3dBi gain antenna is standard. In the same way we can actually measure the attenuation pigtail if we use the two antennas of known gain of its antenna.



Need note that, if the received signal X and Y dBm dBm is the same, then the antenna that we make have the same antenna gain with antenna built-in Access Point is 3dBi.



Usually for the antenna can we gain about 10-12dBi gain.

Source: http://kandangumbara.blogspot.com/

Translated by Google Translate
 
on February, Saturday 26/2011 09:59 by Methos