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Does DCS 1800 interfere to 2500 MHz

Viewing 5 posts - 1 through 5 (of 5 total)
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  • 19th February 2010 at 11:47 #61127
    Azik
    Guest

    Hi Guys

    I’m with a problem:

    1. One cell works with DCS 1800 (2 TRXs). Everything is ok according to DT and Statistic on this site. No any alarm.

    2. But in Spectrum Analyzer we see this cell is interfering to other frequencies (2.5 -2.65 GHz). And guys who use this band (2.5 – 2.65 GHz)are complaing that your frequencies are making problem. After shutting down the site everything is ok, after switching the site it happens again.

    My question is: Is it possible DCS 1800 comes to 2500 MHz in any case? If yes, please tell the probable causes…

    Vendor is NSN.

    Thanks a lot.

    20th February 2010 at 05:04 #61128
    Pix
    Guest

    There might be some intermodulation that falls within the 2.5GHz band. Try changing the frequencies of the DCS site, by choosing 2 frequencies that are nearer.

    By near I mean that insteand of frequencies 700 and 750, choose 710 and 730, for example.

    Cheers
    pix

    20th February 2010 at 16:16 #61129
    Azik
    Guest

    Hi Pix

    What does mean intermodulation? Is it a type of interference or other thing?

    Could you explain details?

    Cheers

    Azik

    20th February 2010 at 16:32 #61130
    pix
    Guest

    hello,

    intermodulation occurs when two frequencies are amplified / combined together. Several additional frequencies are artifically generated (called intermodulation product, or harmonic, of order 2, 3, 4, 5, 6, …).

    You can google it, I’m sure you’ll find a wikipedia entry about it.

    The formula to find what are the harmonics is :
    f(h) = k * f1 + i * f2

    with f1 and f2 the downlink frequencies in MHz

    k and i : integers that vary between -3 to +3 (they can take larger values, but the higher the factors, the lower the power of the harmonic).

    cheers
    pix

    24th February 2010 at 06:33 #61131
    Azik
    Guest

    Thanks Pix

    Realy this information is useful.

    I have one more question:

    If antenna supports GSM1800 & UMTS.
    Is it possible to emite 2.5 GHz frequency???

    Thanks in advance.

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