~ What Is Leakage?
Leakage can be defined as “the
amount of radio frequency (RF) signal
that escapes or infects the cable sys-
tem as a result of one or a combina-
tion of the following factors: improper
cable installation, component corro-
sion, poor product design, vandalism,
cable breaks, poor connections, etc.”
There are two types of leakage, egress
and ingress. Egress is RF signal leak-
age out of the cable system. (See
Figure 1). Egress occurs when cables
are damaged or improperly installed.
Ingress refers to the RF noise or inter-
ference that leaks into the cable sys-
tem (See Figure 2). Ingress occurs
when RF signals emitted from the sur-
rounding environment (e.g. hair dry-
ers, microwaves, radios, welders, etc.)
have the opportunity to enter the
cable system through a break or exter-
nal leak in the cable system. RF or
noise ingress can also feed back into
the coax drop and into the system
from bad TV sets, center conductors
that are too long, customer amplifiers,
VCRs, jumpers, etc.
2-1
Practical Information about Leakage
2
~ How Leakage Egresses into
the Environment
The nature of RF leakage allows a sig-
nal, radiating from a cable system, to
follow any path that provides the least
resistance. Leakage signals may fol-
low paths that include free space,
strand, power, and telephone lines.
Understanding how RF frequency radi-
ate outside of its intended source
helps us to understand why interfer-
ence between frequency signals can
lead to problems.
The illustration provided below indi-
cates how RF frequency signals radiate
out of their source. A typical wavelength
signal is generally 6-9 feet (1-3 meters).
The path that leakage chooses to take
will vary from situation to situation.
FIGURE 1: Egress
FIGURE 2: Ingress at point of Egress
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