User's Manual

EXHIBIT 2 PAGE 9 OF 17
TX RX Systems Inc. Manual 7-9257 (version 1) 11/03/00 Page 9
First we use the conversion chart at the end of this
manual to convert the power levels in dBm to watts
so that we can add them together. The power in
watts is written in scientific notation but the chart
uses computer notation. For example, in the chart,
an exponent may be written as E-08. In conven-
tional mathematical notation E-08 is written 10
-8
.
The total power must be written as a number
between 0 and 10 to use the chart. Look up
1.611E-7 in the Watts column. This number falls
between -38 and -37 dBm so we chose -37
because it is the next higher value.
Reduction of Incoming Signal Strength
Reducing the strength of offending signals may
require some or all of the following steps:
a) The addition of extra filtering. Consult TX RX
System's sales engineers for help in this
respect.
b) Modification of the signal distribution layout by
changing the type or location of pickup anten-
nas. This has to be approached in an empirical
way, that is, change-and-try until you get the
desired results. Sometimes changing from omni
to directional antennas will correct the problem.
Setting Signal Booster Gain
The Pre-Installation checks as outlined earlier
should have been performed to determine if gain
reduction will be necessary for your installation.
This can be due to low antenna isolation or exces-
sive input signal levels, or both. The actual amount
of gain reduction is determined by the largest num-
ber required because of either low isolation or
excessive signal levels.
For example, if the results of the isolation measure-
ment indicated the need for a gain reduction of -10
dB but signal level measurements indicate a need
for only a -5 dB gain reduction; then 10 dB is the
number required since both conditions are satis-
fied.
Gain Reduction Methods
As shipped from the factory, the system was setup
for maximum gain. Gain reduction is accomplished
by adding fixed attenuator pads to the input of the
pin diode attenuator section of the OLC assembly
or where even greater reductions are required,
bypassing one of the first driver amp stages.
Bypassing of amplifier stages is preferred for large
gain reductions so that excessive noise levels are
not produced. Use of attenuator pads alone will
reduce gain but the signal booster will also amplify
the noise generated in the lower level stages. The
correct positions for adding fixed pads to the sys-
tem are shown as dotted symbols on the specifica-
tion drawings.
CAUTION: Any fixed attenuator pads that are
already connected into the booster circuitry have
been installed at the factory and should not be
removed for any reason. Their function may be
other than gain reduction.
A pair of fixed attenuator pads (3 and 6 dB) are
supplied which are mounted in holders on the
inside of the cabinets front door. The pads’ attenu-
ation values are clearly labeled on the body of the
attenuator.
Bypassing Amplifier Stages
Sometimes the amount of gain reduction needed is
greater than the amount available with the attenua-
tor pads alone. In this case, the second stage of
the first driver amplifier may be bypassed. The five
stages of the amp are connected together with
short lengths of coaxial cable. To bypass the sec-
ond stage, remove the coax cable that connects
the second and third stages. Move the cable from
the input connector on the second stage to the cor-
responding connector on the third stage. The input
connector is always the one on the left when facing
the side of the amplifier with the BNC connectors.
Keep in mind that the total gain reduction is the
sum of the added pading plus the loss of gain for
the bypassed amplifier stage. Quality 50 ohm ter-
minations should be installed on the open termi-
nals of any bypassed stage.
OPERATION
Power is applied to the signal booster by turning on
the power supply assembly (see figure 1). The
green LED indicator should come on indicating the
Power (dBm) Power (watts)
-45 dBm
3.16 x 10
-8
-43 dBm
5.01 x 10
-8
-41 dBm
7.94 x 10
-8
TOTAL
16.11 x 10
-8