MD 5850
Installation Manual
Q-Free
®
ASA
645-054-1999 rev.4
19 of 20
Fig.7.1 MultiReader footprint measurements.
4
3
1
2
6
5
Communication
region
Awakening
region
7
MR
8
•
Guiding measurements:
Maximum length of communication zone:
> 3 m (Distance 2 to 3)
Maximum width of communication zone:
> 3 m (Distance 5 to 7)
7.1.3 Spectrum Analyser measurement.
The spectrum analyser must be connected to a left-hand circular polarised antenna with a low loss
coaxial cable. The antenna gain (G) and the cable loss (L) must be known. By pointing the pickup
antenna at the MultiReader at the centre of the TX antenna lobe the maximum signal level is measured.
Example: It is assumed that the MultiReader is mounted 6 m above the road and the antenna angle is 45
degree, with the pickup antenna 1m above the road. The centre of the antenna lobe should then be about
5 m from the projection point of the MultiReader in the horizontal plane through the pickup antenna.
7.1.4 The spectrum analyser settings should be:
Centre frequency:
5.7975, 5,8025, 5.8075 or 5.8125 GHz
Span:
5.0
MHz
Reference level:
-10 dBm
Specification:
Maximum signal level: > -35 dBm +G –L at 8 m distance.
7.1.5 Measurement of the MultiReader footprint with a Spectrum Analyser.
•
Directly towards MR pointing direction:
With the pick-up antenna (1m above ground) pointing at the MR move it to and from the MR and
make a mark on the road where the signal level has fallen 3-dB from the maximum level.
•
Sideways direction:
Start moving the pick-up antenna (pointing at the MR) sideways from the lobe centre, and make a
mark on the road where the signal level has fallen 3 dB form the maximum level.
•
Guiding measurements:
Maximum length of - 3 dB zone:
> 2 m
Maximum width of -3 dB zone:
> 2 m