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We should ensure the line of sight in microwave Links.
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Line of sight mean the near end and far end dish antennas should be on the same line of sight.
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This is achieved by the process called alignment.
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To perform alignment we need avometer, laptop, login cable, NMS like weblct or minilik craft depends on the magazine type.
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Magazine is the indoor unit of microwave Link.
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Before alignment we should ensure the link installed as per azimuth, height, tilt of the planning sheet.
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To satisfy the performance from the microwave Link we should ensure the area between near end and far end of microwave Link is clear of obstacles.
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Obstacles can be trees, buildings, flags, bulbs…
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Fresnel zone is ellipsoid shaped zone around the line of sight.
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This ellipsoid zone has radius, calculated based on frequency range of the link and distance between near end and far end.
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We should keep the 1st fresnel zone 100% Free of obstacles.
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If we got obstacle inside the fresnel zone we have to:
- change antenna height
- try repeater or reflector
- try reroute the link
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As frequency decreasing and distance increasing, the fresnel zone radius increase too.
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For example: if frequency 4 GHz, distance 70 km, radius will be 36 meter.
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For example: if frequency 38 GHz, distance 5 km, radius will be 3 meter.
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For example, E band 80 GHz, distance 1 km, radius is only 1 meter.
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