User's Manual

EXHIBIT 2 PAGE 6 OF 17
TX RX Systems Inc. Manual 7-9257 (version 1) 11/03/00 Page 6
of and help you to avoid the areas where experi-
ence has shown us that trouble can occur.
1) Just like the feedback squeal that can occur
when the microphone and speaker get too
close to each other in a public address system,
a signal booster can start to self oscillate. This
will occur when the isolation between the input
antenna or signal source and the output distri-
bution system does not exceed the signal
boosters gain by at least 15 dB. This condition
will reduce the effectiveness of the system and
may possibly damage the power amplifier
stages.
2) The major cause of damage to signal boosters
is the application of input RF power levels in
excess of the maximum safe input. This can
happen inadvertently when connecting a signal
generator with full power out to one of the inputs
or by a very strong signal that is far stronger
than expected. Following the pre-RF connection
checks listed next will help to avoid these two
problems.
PRE-RF CONNECTION TESTS
Certain characteristics of the signal distribution
system should be measured before connecting it to
the signal booster. This step is necessary to insure
that no conditions exist that could possibly damage
the signal booster and should not be skipped for
even the most thoroughly designed system. Two
characteristics need to be measured; antenna iso-
lation and input signal levels.
Test Equipment
The following equipment is required in order to per-
form the pre-installation measurements.
1) Signal generator for the frequencies of interest
capable of a 0 dBm output level. Modulation is
not necessary.
2) Spectrum analyzer that covers the frequencies
of interest and is capable of observing signal
levels down to -100 dBm.
3) Double shielded coaxial test cables made from
RG142 or RG55 coaxial cable.
INTERNAL
SIGNAL DISTRIBUTION
SYSTEM
SPECTRUM
ANALYZER
EXTERNAL
ANTENNA
SIGNAL
GENERATOR
ZERO LOSS
REFERENCE
ISOLATION (dB)
Figure 2: Typical test equipment setup for measuring antenna isolation.