Consonics CyberTek Qualifier, Руководство пользователя

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Qualifier Supplement
8
The CATV cabling inside a residence is usually hidden in areas such as craw spaces, behind
walls, attics, and basements. The effects of aging on the cable (especially metal connectors),
rodent damage, and possibly improper installation reduce the shielding integrity of the
system within the residence. Poor shielding integrity allows the inside cabling to become a
receiving antenna for interfering signals. A signal or noise entering (ingress) the internal
cabling has the possibility of traveling to the upstream path and causing problems.
Since all residences have the potential to cause problems in the upstream path, a test is
needed to qualify each individual residence. If the internal cabling is susceptible to ingress
from devices within the residence, then it will also have ingress from a known signal source.
The known signal source is a mobile transmitter operating on a frequency in the 5 to 50
MHz range. The mobile transmitter is usually mounted in a service vehicle and powered
from the vehicle. The mobile transmitter also has a feature of variable power output. An
omni-directional antenna is connected to the transmitter and mounted on the vehicle. The
antenna is best mounted on the vehicle roof in an area clear of other metallic objects such as
other antennas, ladders, and lifting apparatus. The vehicle is parked adjacent to the dwelling
(within 100 feet) and the transmitter is powered on. The residence is radiated with the test
signal. Test signal frequency should be chosen as not to cause interference with known
upstream communications.
Inside Cables
Drop Cable
Ground Block
Local Tap
Service Vehicle
Transmitter
Antenna