SnapShot Camera Installation Guide
Page 7 of 12
5. Field Cables
ANPR processors requires a high quality video signal to achieve maximum
accuracy and care should be taken to ensure that the signal is not
degraded during transmission. Coaxial cable is preferred for transmitting
the video signal, although high quality passive baluns used in conjunction
with a twisted-pair cable are generally fine for cable distances up to 170
metres.
For longer cable distances, the transmission system should be designed
with great care to ensure that the video level at the receiver is close to
1vpp and that the full frequency range of the video signal is maintained. If
any form of digital conversion is used, the received analogue signal should
be at least 25fps (50fps for high speed traffic), full resolution (D1) and with
no visible compression artefacts.
With regard to the 24v ac power supply, please ensure that the conductor
size is sufficient for the length of cable run to avoid more than a 10% volt
drop.
Finally, for long telemetry cable runs we would recommend a low
capacitance cable such as Beldon 8132 which will normally allow
distances of over 1000m to be achieved. For shorter distances, standard
Cat5 or Cat6 cabling may be used. Ensure that a twisted pair is employed.
6. Cleaning
Keeping the window clean will help reduce image degradation. The
camera window is made from float glass and just requires a wipe with a
wet cloth. Finish with a dry cloth or allow to dry naturally.