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Thread: How to analyze antenna frequency response using Chanalyzer

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    Default How to analyze antenna frequency response using Chanalyzer

    Here is an example of using Chanalyzer to check frequency response of antenna.



    As you know, antenna has limited bandwidth, and usually cannot cover whole band. Consequence is that signal is better on some frequencies and worse on others. It is good to know which frequencies antenna matches, so use it there.

    You can roughly check how antenna responds on different frequencies. Just connect it to an AP, and start scanning using WiSpy. Change channels from first to last on band, and each time leave enough time for WiSpy to scan enough data to allow Chanalyzer to display visible pattern. After you recorded all channels graph will show you how antenna responds to different frequencies. Channel with highest level is the one that antenna matches the most. Some antennas are tuned to one channel, some cover several channels and rare ones cover whole band.

    You may check example i attaches. You may notice that antenna matches channels 2 to 5, as that is where signal level is highest.

    Pay attention that this method is not very precise, as it actually measures sum of frequency responses of all elements involved: not just measured antenna, but also transmitting device, receiving antenna and WiSpy device too.

    I made this measurements using WiSpy 2.4x with 2 dB antenna I got with it. Result matched expectations as I got this antenna as tuned for channel 3. Antenna is Slotted Wave Guide with 16 + 16 slots.
    Last edited by MetaGeek; 10-22-2009 at 04:20 PM.

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