User`s manual

100-M0056X2B 4 of 28
www.cobham.com/gms
1.0 Important Warning and General Safety Information
The following information is presented to the operator to ensure awareness of potential harmful
RF (radio frequency) exposure and general hazards. With regards to potential harmful RF
electromagnetic fields the text below is only a brief summary highlighting the possible risks and how
to minimize exposure. The summary is based on OET Bulletin 65 “Evaluating Compliance with FCC
Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields”
(1)
. The user should
carefully read and comprehend the following before operating the equipment and for additional in
depth information refer to OET Bulletin 65.
1. FCC has set guidelines
(1)
for evaluating exposure to RF emissions that the user must be aware of when
operating GMS’s MDT-B microwave transmitter. The maximum power density allowed at 1500 –
100,000 MHz is 5mW/cm
2
for occupational/controlled exposure* and 1mW/cm
2
for general
population/uncontrolled exposure**. These are the limits for maximum permissible exposure (MPE) as
called out in the FCC guidelines (for the above mentioned frequencies).
2. Exposure is based on upon the average time spent within the RF field with a given intensity (field units
in mW/cm
2
). Hence it may be controlled (or at least minimized) by observing the safe distances and
time exposed as shown in Table 1. These safe distances are calculated from equations predicting RF
Fields
(3)
with the following assumptions:
• The transmitter maximum power is 23dBm (0.2W)
• The antenna used has a 2dBi gain
• The transmitter is used in a fixed location
* “Occupational /controlled exposure limits apply to situations in which persons are exposed as a
consequence of their employment and in which those persons who are exposed have been made fully
aware of the potential for exposure and can exercise control over their exposure.
Occupational/controlled exposure limits also apply where exposure is of a transient nature as a result of
incidental passage through a location where exposure levels may be above general
population/uncontrolled limits (see below), as long as the exposed person has been made fully aware of
the potential for exposure and can exercise control over his or her exposure by leaving the area or by
some other appropriate means. …….”
(2)
** “General population/uncontrolled exposure limits apply to situations in which the general public may
be exposed or in which persons who are exposed as a consequence of their employment may not be
made fully aware of the potential for exposure or cannot exercise control over their exposure.
Therefore, members of the general public would always be considered under this category when
exposure is not employment-related, for example, in the case of a telecommunications tower that
exposes persons in a nearby residential area.”
(2)
(1)
OET Bulletin 65, Appendix A Table 1 Limits for MPE
http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet65/oet65.pdf
(2)
OET Bulletin 65, page 9, definitions of types of exposure
http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet65/oet65.pdf
(3)
OET Bulletin 65, page 19, Equations for predicting RF Fields
http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet65/oet65.pdf
The user (and bystanders) should remain beyond the distances from the antenna at all times as stated in
Table 1 when the transmitter is operating for no longer than the time periods indicated (keeping in mind
this is the average time).