Park Air Systems T6TR, User Documentation

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T6TR VHF 50 W Transceiver Page 28 Installation
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Chassis Stud Connection
A chassis stud is fitted to the transceiver's rear panel. This stud is used to connect the
equipment to the equipment rack, or to the user's system earth point. The stud must not be
used as the safety earth.
In order not to compromise the transceiver’s Electromagnetic Compatibility (EMC) the chassis stud,
marked
and fitted to the rear panel (see Fig 12 ) must be connected to the equipment rack (if a rack
is being used) or to the user's system earth point. The connection should be made using a single tri-rated,
green-and-yellow cable having a cross-sectional area of 2.5 mm
2
. The cable should have CSA and
UL1015 approval, and be connected to the chassis stud through an M6 eyelet (for example, Park Air part
number 20-08010103).
Failure to comply with this instruction could result in non-compliance with the European Commission
EMC Directive 89/336/EEC.
Connect the Antenna(s)
The antenna connectors are N-type sockets suitable for connecting a 50 ohm antenna. Make a
connection to the TX/RX connector if using a single antenna, or the TX/RX and RX connectors if separate
transmit and receive antennas are to be used. The antenna configuration must conform to the
transceiver’s internal coaxial link arrangement (see
Setting the Required Antenna Configuration on
page 14 ).
The antenna used with the transceiver must be installed such that the resultant radiated field
strength is below 10 W/m² in areas normally accessible to personnel.
The RF field strength from the antenna can be predicted from the equation S=1.4PG/4
π
R
2
[Where S = power density; P = power input to antenna; G = antenna gain; R = distance
to centre of radiation and 1.4 = multiplication factor for average power based on a
modulation index of 90%.]
Based on this formula for a 50 watt transmitter and using a 0 dBi antenna, the predicted safe
distance from the centre of radiation would be approximately 0.75 m for a field strength of 10 W/m
2
(1 mW/cm
2
).
This meets the requirements of Health Canada Safety Code 6 for RF and microwave exposed
workers. For persons not classed as RF and microwave workers and including the general public
the limit is 2 W/m
2
(0.2 mW/cm
2
) which increases the minimum safe distance to 1.7 m.
Further information on calculating the field strengths and power levels can be found in Health
Canada Safety Code 6 'Limits of Human Exposure to Radiofrequency Electromagnetic Fields in the
Frequency Range 3 kHz to 300 GHz', and also in FCC document OET Bulletin 65.
WARNING Chassis Earth
WARNING
Antenna Radiation