Park Air Systems 6525, User Documentation

Page: 46 / 54

31-3MDR00HB Page 46 Installation
Draft
Connecting the Chassis Stud
A chassis stud is fitted to the MDR'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 MDR’s Electromagnetic Compatibility (EMC) the chassis stud, marked
and fitted to the rear panel must be connected to the equipment cabinet (if a cabinet 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.
Connecting an Antenna
The antenna used with the MDR 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 a 2 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.
Ensure an antenna, or dummy load, is connected before switching on the MDR. There is high
RF voltage present at the antenna connector when the radio is keyed.
The MDR uses a common antenna for transmission and reception. The rear panel N-type (female)
antenna connector accepts a straight or right-angle N-type plug as listed in
Table 9 on page 39 . Park Air
recommends that RG214 1/2” flexible feeder cable, part number 10-05120610, be used for that part of
the feeder circuit that is within a building.
WARNING Chassis Earth
WARNING
Antenna Radiation
WARNING
Antenna Radiation