User's Manual

61-38-05 UserMan page 20 of 38
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 20
nected to pin 4. Relay K1 is de-energized when the
AC power supply is off.
PERFORMANCE SURVEY
It is a good idea to document the performance of
the system after installation so that a reference
exists for future comparisons. This information can
make troubleshooting an interference problem or
investigation of a complaint about system perfor-
mance much easier. If there are coverage prob-
lems with a system, this survey will usually reveal
them allowing corrective measures to be taken
before the system is put into routine use. The fol-
lowing is an outline of how to do such a survey.
Because the nature of each installation can be
quite different, only a broad outline is given.
1) Measure the gain of the signal booster being
careful not to exceed the maximum input level.
Figure 9
shows this being done using a signal
generator and spectrum analyzer. This is basi-
cally a substitution measurement. Record the
measured values for each passband.
2) Each branch of the signal booster system is
equipped with a -50 dB signal sampler port fol-
lowing the final output amp (part of the OLC
assembly). This port is for the connection of test
equipment such as a spectrum analyzer and
will allow the observation of the amplifier output
at a considerably reduced output level. This
decoupling figure needs to be added to a mea-
sured signal value in order to arrive at the actual
signal level. OLC assemblies appear in sche-
matic representation on the specification draw-
ings.
3) With a spectrum analyzer connected to the sig-
nal sampler port for the branch under test (see
Figure 10
), have personnel with handheld
radios move to predetermined points and key
their radios. Record the level of these signals as
observed on the analyzer and also record the
location of the person transmitting. In this way, a
map of the systems performance can be gener-
ated.
4) For branches that amplify signals coming from a
fixed antenna or station, record the level of all
the desired incoming signals for future refer-
ence.
FIELD ADJUSTMENTS
The following information is provided in support of
field support activities, including routine mainte-
nance, repairs, adjustments and tuning. It is
DC
Sampler
Sampler
Detector
Electronic
Attenuator
OLC Assembly
Filter
Filter
Amp
DC
Control
ZERO
REFERENCE
GAIN
10 dB Pad
SIGNAL
GENERATOR
SPECTRUM
ANALYZER
Figure 9
: Test equipment interconnection for measuring signal booster gain.