INSTALLATION NOTES
•Compliance of base station transmitter installa- tions with EN50385
The installation of this equipment and it’s associated antenna should be made in such a manner as to respect the EC recommended electromagnetic (EM) field exposure limits. (1999/519/EC)
In order not to exceed these exposure limits it is necessary to determine the ‘Compliance Boundary,’ that means the volume within which the EM field radiated by the transmitter/antenna installation may exceed the 1999/519/EC limits. You will then need to ensure that members of the general public do not have access within this area. The actual Compliance Boundary for this repeater will be totally dependant on the antenna, feeder, RF amplifier and other passive or active devices used in the installation.
The RF output power of this repeater is 25 watts.
The figures contained in this guide are based on the recommended limits for the general public and are obtained by ‘worst case’ numerical analysis. For a definitive evaluation of any given installation, measurements should be made with an EM field meter and a broadband calibrated probe.
• Installation
The antenna should be installed as high as possible for maximum efficiency and minimum EM field at
If there are any objects or structures larger than half a wavelength close to the antenna, or within the clearance distances specified, then these can cause reflections which will have an effect on the overall radiation pattern.
For any installation you need to consider ‘height clear- ance’ (i.e. the height above any place where persons may have access) and ‘front clearance’ (i.e. the distance in front of the antenna where the radiated field may exceed the recommended limits). Normally with an antenna installed on a reasonably high mast or tower, there will not be any access point directly in front but care should be exercised when there are other buildings higher than the antenna within the vi- cinity.
ABOUT CE 6
•Installation with a vertical type antenna at VHF-
UHF
You need to consider the distances between the antenna and any point where persons may have access. Allowing an average height of 1.8 m for a person in the vicinity of the antenna the clearance distances can be evaluated as follows. For the antenna a forward gain of 1.6 and downward gain of unity has been assumed.
Power | EIRP | Distance | Height | Front | 1 | |
clearance clearance | ||||||
1 watt | 1.6 watts | 0.32 m | 2.1 m | 0.4 m | 2 | |
10 watts | 16 watts | 1 m | 2.8 m | 1.3 m | ||
25 watts | 40 watts | 1.6 m | 3.4 m | 2 m | 3 | |
100 watts | 160 watts | 3.2 m | 5 m | 4 m | ||
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1 kW | 1600 watts | 10 m | 12 m | 13 m | 4 | |
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• Installation with a yagi or directive type antenna | 5 | |||||
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Exposure distance assumes that the predominant ra- | 6 | |||||
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diation pattern is forwards and that radiation vertically |
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downwards is at unity gain (sidelobe suppression is | 7 | |||||
equal to main lobe gain). This is true of almost every | ||||||
gain antenna today. Exposed persons are assumed | 8 | |||||
to be beneath the antenna array and have a typical | ||||||
height of 1.8 m. |
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The figures assume the worst case emission of con- | ||||||
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stant carrier. |
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RF power | Clearance heights by frequency band | 11 | ||||
Watts | 70 cm | 23 cm | 13 cm | 12 | ||
and above | ||||||
1 | 2.1 m | 2 m | 2 m | 2 m | 13 | |
10 | 2.8 m | 2.7 m | 2.5 m | 2.3 m | ||
25 | 3.4 m | 3.3 m | 2.7 m | 2.5 m | 14 | |
100 | 5 m | 4.7 m | 3.6 m | 3.2 m | ||
1000 | 12 m | 11.5 m | 7.3 m | 6.3 m | 15 | |
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EIRP | Forward clearance, EIRP by frequency band | 16 | ||||
Watts | 70 cm | 23 cm | 13 cm | |||
and above | 17 | |||||
100 | 2 m | 2 m | 1.1 m | 0.7 m | ||
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1000 | 6.5 m | 6 m | 3.5 m | 3 m | ||
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10,000 | 20 m | 18 m | 11 m | 7 m | 19 | |
100,000 | 65 m | 60 m | 35 m | 29 m | ||
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