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Electrical Tilt Formula

Viewing 15 posts - 1 through 15 (of 29 total)
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  • #53193
    Mohit
    Guest

    Hi All…

    One of my friend has recently gone through an interview…and the interviewer asked him two questions…

    1) wat is the formula for calulating/ deciding electrical tilt for a site.

    2) how many TCH are required during a Confrence call..

    Pls do reply if somebody have any idea regarding these above question…

    Regards..
    Mohit..

    #53194
    pix
    Guest

    1> geometrical calcula : depending on height of antenna, expected cell range and vertical aperture of the antenna, one can compute the required tilt in order to locate the upper “-3dB” point onto the cell range.
    f(H, CR and VHPBW) –> tilt
    the formula uses “tan” function… i let you find it by yourself 🙂

    2> only one TCH per user.

    #53195
    Mohit
    Guest

    Thanks Pix…

    But can u explain this formula a little more…i mean with an example…

    Regards..
    Mohit

    #53196
    pix
    Guest

    Mohit,

    i hope you didn’t kill yourself trying to find the formula, huh.

    cell range = Height BTS / (tangent(tilt – VHPBW/2))

    example : height = 30m
    VHPBW = 8 degrees
    tilt = 6 degrees

    –> cell range = 30/tan(radians(6 – 8/2)) = 859 meters.

    #53197
    Mohit
    Guest

    Many Many thanks Pix…
    🙂

    #53198
    MKT
    Guest

    Pix..

    How will you find the 3 dB point from BTS?

    Does the formula takes into account the BTS Tx Pwr Max?

    Regards

    MKT

    #53199
    pix
    Guest

    the 3dB upper point is taken into account in the formula (–> VHPBW/2)

    the BTS power does not matter in this formula. What matters is how far you want to locate your “3dB upper point” (=cell range). The BTS power will then give you the “intensity” of the coverage within this cell range.

    regards
    pix

    #53200
    MKT
    Guest

    Pix

    what is VHPBW?

    Regards

    #53201
    pix
    Guest

    vertical half power beam width… it is the vertical “aperture” of the antenna. You can see it on the antenna specifications. Usually around 8 degrees.

    #53202
    Nitin Tomar
    Guest

    What is the significant of Vertical beamwidth in coverage???

    #53203
    Pix
    Guest

    Nitin, isn’t it explained just one post below ?

    #53204
    baig
    Guest

    Is the tilt in the formula got from sum of electrical and mechanical tilt or its just the electrical tilt? how does mechanical tilt affect the formula

    #53205
    Pix
    Guest

    In the formula, you should use the sum of electrical tilt + mechanical tilt.

    #53206
    Ahsan
    Guest

    I really acknowledge ur effort regarding helping other optimizers and learners..

    Well it means that we have to take effective tilts into account.

    Also i wanted to know the individual effect of mechanical and electrical tilt.

    Well as i have experienced.. mechanical tilts adds backlobes.. question is Y.?

    #53207
    Pix
    Guest

    Hello,

    Mechanical tilt : increase downtilt in front, but since you’re tilting the whole antenna, you see that the backlobe will get uptilted, yes? ,

    Electrical tilt: all directions around the antenna are tilted down, like when you’re closing an umbrella : all sides are getting down at the same time.

Viewing 15 posts - 1 through 15 (of 29 total)
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