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Microwave Transmission

Viewing 15 posts - 76 through 90 (of 114 total)
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  • #38388 Reply
    Techie
    Guest

    why we use in some cases vertical polarization & horizontal polarization

    #38389 Reply
    Imran Sabir
    Guest

    Hi everyone,
    Can any body tell me,what is the effect oh HI-LO Voilation on the network while designing a Ring Topology?
    Is it true that performance degradation in 26GHz band is more severe than 38GHz band,due to Rain?

    #38390 Reply
    Imran Sabir
    Guest

    Hi everyone,
    Kindly give me the answer that,
    Why RSL(Recieved Signal Level) is in dbm while Fade Margin is in db?

    #38391 Reply
    Imran Sabir
    Guest

    Hi Techie,
    actually the selection of polarization depends upon the different prameters.
    Vertical polarization is more effective against rain.
    Vertically polarized waves are less effective to multipath fade in lower frequencies.
    vertical polarized wave give us 30% more RSL as compared to the Horizontal polirized wave.
    The reason for using both H & V polarizations is to get maximum use of frequency in th network with out interference.

    Hopefully this will help you

    #38392 Reply
    Pix
    Guest

    Hi sabir,

    A received level is the measurement of an absolute power, that corresponds to miliwatts for instance. So that’s dBm.

    The fading margin is an attenuation, that is a relative difference in power. And that’s not an absolute power, that can’t be express in milliwatt. It is relative… So it’s dB. A certain power – 3dB, means the power (whatever value it actually was) is divided by 2.
    -6 dB = power divided by 4
    – 9 dB = divided by 6

    #38393 Reply
    Imran Sabir
    Guest

    thx Pix,

    But my concern is that,
    FM=Rx Sensitivity(dbm)- RSL(dbm)

    if both RSL & Rx Sensitivity are in dbm,how FM is in db?

    #38394 Reply
    Techie
    Guest

    Hi Imran Sabir,

    Thanks for your reply, i wanted to ask you one more thing that is there any distance limitation in using the H and V Polarizations in the frequency bands

    #38395 Reply
    saadia
    Guest

    hello everyone!
    i want to know about path losses in GSM 1800.can anybody tell me what is the link balance?

    #38396 Reply
    Ahmed
    Guest

    why we use in some cases vertical polarization & horizontal polarization.pls answer me

    #38397 Reply
    Winet
    Guest

    patrick.fr – 4 Apr 2007

    Could you explain me what you meant?
    ODU HS = Hot Standby?
    Link is made on Ericsson Mini Link TN equipment, I’m sure there is 1+0 option checked. How ODU can be HS in this case?

    #38398 Reply
    nizar
    Guest

    can anybody tell me which all countries use alcatel bts for installaTION………………………………………………

    #38399 Reply
    Imran Sabbir
    Guest

    Hi Winet,
    to me it seems that your link is getting interference from some other source.Contact your Transmission Planner to verify if there is any interference on that link or not.

    #38400 Reply
    Imran Sabir
    Guest

    Hi Techie:
    Is there any distance limitation in using the H and V Polarizations in the frequency bands?

    Hop distance is not dependent on the polarization,rather it is frequency dependent. Anyhow at smaller frequncies,H polarized wave suffer more multipath fading than V polarized wave,while in upper frequency bands,H polarized waves suffer more Rain fading than the V polarized waves.

    #38401 Reply
    Techie
    Guest

    Can anyone tell me the RSL Levels for Frequency bands

    #38402 Reply
    pix
    Guest

    Hi Sabir,

    sorry for the late reply.
    by substracting two powers, you obtain a delta of power.
    And a “delta” is an attenuation…

    dBm – dBm = dB

    that’s correct.

    a dB is a difference (or “delta”) between two powers expressed in dBm. Maybe you should refer to wikipedia if you want a more mathematical approach of this…

Viewing 15 posts - 76 through 90 (of 114 total)
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