YDI Link CX-24, Руководство пользователя

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Link CX-24 User’s Manual
Version 1.0 Page 13 February 2004
direct signal path. The Fresnel zone surrounds the direct signal path, so it affects objects to the side of
the path as well as objects directly in the path.
For a calculation of the Fresnel Clearance Zone, please refer to:
http://www.ydi.com/calculation/fresnel-zone.php .
Multipath Fading: See Figure 2.1. Because a Link CX-24 terminal typically transmits its strongest signals
in a cone-shaped pattern, some of the signal may be reflected from a nearby building, from water under
the signal path, or from other RF reflectors. This reflected signal can then be received by the far-end Link
CX-24 and superimposed on the main signal, usually degrading the signal strength. To avoid multi-path
fading, YDI recommends that you install the Link CX-24 antenna on the back, rather than the front, of
buildings to avoid multi-path fading from water or other ground-level surfaces, and that you plan radio
links away from nearby buildings.
Figure 2.1 – Preventing Multi-path Fading from Ground-Level Surfaces
External Interference:
Because the Link CX-24 operates in an unlicensed band, YDI strongly
recommends that you use a spectrum analyzer at both ends of planned radio links, with the receiving
antenna as close to the proposed Link CX-24 antenna mounting spot as possible. Use a polarized
antenna, and scan for both horizontally- and vertically-polarized interfering radiation. If you find external
interference in either of the two (High or Low) bands, configure the Link CX-24 for the least-impacted
band. Refer to Table 2.2 for the High and Low bands for the Link CX-24 radio.
2.3 Site Planning
Each proposed Link CX-24 terminal site requires a site survey and plan for the following:
Power: The Link CX-24 radio requires a +/-21 to +/-60 VDC power source. Make sure required power
supply is available before installing the Link CX-24.
Mounting Point: The Link CX-24 is usually mounted on a vertical mast or pole mounted on a building or
a tower. The Link CX-24 mounting bracket can accommodate a 4.5 to 7.6cm (1.75” to 3” OD) diameter
mast or pole.
Grounding and Lightning Protection:
The Link CX-24 radio requires adequate grounding and lightning