User's Manual
2
Experts in science, engineering, medicine, health, and industry work with organizations to develop standards for safe
exposure to RF energy. These standards provide recommended acceptable levels for personnel who may be exposed to
RF energy. The RF exposure levels described therein include substantial margins of protection.
When properly installed and used, Crescend power amplifier products meet all
government-established
RF exposure
levels. In addition, Crescend recommends specific operating instructions for users of its power amplifier products. These
instructions are important because they inform users about RF energy exposure and provide simple procedures on how
to control it.
Please refer to the following Web sites for more information on the nature of RF energy exposure and how to control your
exposure to assure compliance with established RF exposure limits.
http://www.fcc.gov/oet/rfsafety/rf-faqs.html
http://www.osha.gov/SLTC/radiofrequencyradiation/index.html
Federal Communication Commission Regulations
The FCC rules require manufacturers to comply with the FCC RF energy exposure limits for communication devices
before they can be marketed in the U.S. The FCC further requires users to be fully aware of and able to control their
exposure to meet RF energy exposure limits. This document includes operating instructions and information required to
control your RF exposure and to satisfy compliance requirements.
RF Exposure Compliance, Control Guidelines and Operating Instructions
To control exposure to yourself and others and to ensure compliance with the RF exposure limits, always adhere to the
following guidelines.
• Crescend power amplifier products are intended for use in fixed communication locations (e.g. base station sites). The
antenna installation must comply with the following requirements to ensure optimum performance and compliance with
the RF energy exposure limits required by the FCC.
1) The antenna should be mounted outside the site building on a roof, tower, or other support structure such that
its location is inaccessible to personnel within the Minimum Permissible Exposure radius (see below).
2) The licensee must undertake the responsibility to manage the site in accordance with the applicable regulatory
requirements. This may include, but is not limited to, providing advisory notices to all personnel who may be
exposed to RF energy in the vicinity of the antenna, restricting access to areas adjacent to the antenna, or
ceasing use of the power amplifier when RF energy exposure safety cannot be guaranteed.
• When the power amplifier is operating, a front panel LED will be illuminated. The power amplifier will be generating
measureable RF energy exposure when transmitting.
• The maximum permissible exposure (MPE) radius is unique to each base site installation and is based on several
factors such as the transmitter power output level, antenna gain, feed line loss, etc. It is the responsibility of the licensee
to determine the MPE for the base site installation.
1) For 300 to 1500 MHz operation, the maximum exposure limit is determined by the expression…..
S =
f
2
mw / cm
1500
where f = frequency in MHz
2) An example calculation of the MPE radius for a 50 Watt UHF transmitter installation having a 5 dBi gain antenna
and 1dB of feedline loss is provided below:
Po
=
50000
dBd = 2.85
mWatts
antenna gain in dBd
f
=
403
- 450 MHz
G1
=
dBd + 2.15
gain in dBi
S =
f
1500
= 0.3
mW
cm
G1
=
5
CL
=
1.0
G =
G1
- CL
G
Gn
=
10
10
Gn = 2.512
dBi
dB
coax loss
gain (numeric)
See 47
CFR
1.1310
R =
(Po
•
Gn)
4
π
•
S