COOPER INDUSTRIES INC FHOEM-900 Manuale Utente

USER MANUAL

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NOTE:  The FCC and ISC require that the antenna be restricted to that supplied
by the manufacturer and approved for use with this product.  A 0dB quarter-
wave omni antenna is normally supplied.  For other antenna options, please
contact OMNEX Control Systems Inc.

It is important for proper operation of the OEM-900 that when multiple

systems are to be installed, there is ample space between the antennas.

There must be a minimum of 3 feet (1 meter) vertical and 10 feet (3

meters) horizontal separation between the transmitter of one system and
the receiver of another.  As well, when these units are used in a repeater
fashion, the 3 foot (1 meter) vertical separation must also be adhered to.

4.1  Height

For maximum transmission effectiveness, several factors must be taken into account.  Obviously, distances between
antennas are important, as radio signals dissipate as they travel.  The Fresnel Zone, or the space occupied by the
propagating radio signal, changes shape as it travels across the earth, and must be relatively clear of obstacles.  For
distances greater than 7 miles (11 kilometers), the curvature of the earth can adversely affect the radio link.  As a
result, the overall formula for calculating approximate total antenna heights is:

Where:

H = antenna height in feet
D = distance between radios in miles

To simplify this, refer to Figure 4.1-1 to find the suitable minimum height of the antennas at each end of the link.

H =  13.7       D  + D

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