MT-MR PLATINUM. POINT TO POINT AURAL RADIO RELAY SYSTEM
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GAIN OF ANDREW® MESH PARABOLIC REFLECTORS
Reflector Gain at 1.9/2.3 GHz Frequency Band.
Diameter (dBi)
(m) 1.9 GHz 2.0 GHz 2.1 GHz 2.2 GHz 2.3 GHz
0.6 18.2 18.7 19.0 19.5 19.9
0.7 19.6 20.0 20.5 20.9 21.3
0.8 20.8 21.2 21.6 22.0 22.4
0.9 21.9 22.2 22.7 23.0 23.6
1.0 22.9 23.1 23.7 24.0 24.4
1.2 24.2 24.9 25.2 25.7 26.1
1.4 25.8 26.2 26.7 27.0 27.5
1.5 26.3 26.9 27.2 27.8 28.0
1.8 28.0 28.5 28.9 29.3 29.8
2.0 29.0 29.4 29.9 30.1 30.6
2.4 30.6 31.0 31.5 31.9 32.1
2.5 30.9 31.3 31.8 32.1 32.8
2.8 31.9 32.5 32.9 33.2 33.7
3.0 32.5 33.0 33.5 33.9 34.2
3.5 33.9 34.4 34.9 35.1 35.6
4.0 35.1 35.5 35.9 36.2 36.8
4.5 36.2 36.7 37.0 37.4 37.9
From former Table can be easily selected the required antenna. For the system frequency used and required gain,
the mesh parabolic reflector required is of 2.4 m diameter, installed at both ends, transmitter and receiver.
Once these calculations are finished, we can analyze the remaining factors of interest in System's calculations,
such as:
a) Path Attenuation for 0.1 % of Operating time:
The expression is as follows: A
0.1
= 45 log d + 30 log f +78 [dB]
In our example, replacing numerical values:
A
0.1
= 249.4 dB
This will be the value of Free Space Attenuation in Fading condition, predicted for 1x1000 of total operating time.
b) CCIR Margin for 0.1% of Total Operating Time:
The expression is as follows: M
0.1
= 35 log d - 10 log p + 10 log f - 78.5 [dB]
Where: p = Probability of Occurrence of Fading, generally taken about 0.01, in a general form p« 0.2 .
In our illustrative example: M
0.1
= 30.6 dB
This is practically the limit of this parameter. It never will be lower than 30 dB.
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c) Percent of time in which this margin will be exceeded:
Expression for this Calculation is the following: % T = 0.1 (d)/2500 [%]
