Park Air Systems Limited B6525MDR Manuel D’Utilisation

31-3MDR00HB

Page 4

Draft

The instructions given in this documentation involve connecting dangerous voltage to the MDR.
Installation must be carried out only by suitably qualified personnel.

This equipment must be earthed. The earth terminal of the ac connector must be used as the safety
earth.

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

πR

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.

Although no instructions in this documentation involve removing any equipment covers, users
should be aware that the RFPA output transistors contain Beryllium.

During installation an MDR may have to be lifted, possibly to head height, to fit onto telescopic slides.
At least two people should be used to lift the equipment. Failure to use sufficient people when lifting
equipment can result in personal injury.