Campbell Scientific RF450 Spread Spectrum Radio - Manual (Page 23)

RF450 Spread Spectrum Radio
FCC OET Bulletin No. 63 (October 1993)
Changing the antenna on a transmitter can significantly increase, or decrease,
the strength of the signal that is ultimately transmitted. Except for cable
locating equipment, the standards in Part 15 are not based solely on output
power but also take into account the antenna characteristics. Thus, a low
power transmitter that complies with the technical standards in Part 15 with a
particular antenna attached can exceed the Part 15 standards if a different
antenna is attached. Should this happen it could pose a serious interference
problem to authorized radio communications such as emergency, broadcast,
and air-traffic control communications.
In order to comply with the FCC RF exposure
requirements, the RF450 series may be used only with
approved antennas that have been tested with this radio
and a minimum separation distance of 20 cm must be
maintained from the antenna to any nearby persons. CAUTION
4.2 Antenna Cables and Surge Protection
4.2.1 Antenna Cables
The 14201, 14221, 19512, and 20XXX antennas require an antenna cable;
either (1) the COAXSMA-L cable or (2) the COAXNTN-L cable with surge
protector. Indoor omnidirectional antennas are either supplied with an
appropriate cable or connect directly to the radio.
4.2.2 Electrostatic Issues
Many RF450 series installations are out of doors and therefore susceptible to
lightning damage, especially via the antenna system. Also, depending on
climate and location, electro-statically charged wind can damage sensitive
electronics if sufficient electric charge is allowed to accumulate on the antenna
and cable. To protect against this, Campbell Scientific offers the Item # 19533
Antenna Surge Protection Kit.
Antenna surge protection is recommended in the following applications:
• When the antenna cable length exceeds 10 feet
• When use of COAXSMA cable would result in too much signal loss
• When the radio will be used in an environment susceptible to lightning or
electro-static buildup
4.2.3 Antenna Surge Protector Kit
The Surge Protector Kit includes the following:
• Polyphaser protector
• COAXSMA-L cable with 1.5 ft length (its type N male connector fastens
to the polyphaser’s equipment connector; its SMA connector fastens to the
radio’s antenna connector)
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