Manual 7-9415-1.4 Page 18
TX RX Systems Inc. 08/31/06
61-65-50 UserMan page 18 of 24
operation and red a fault condition. A fault condition
for the +24 VDC supply occurs whenever the volt-
age potential drops below +16 VDC (30% below
nominal). Likewise, a fault for the +12 VDC supply
occurs when the potential is below +8 VDC (30%
below nominal).
FORM-C CONTACTS
Form-C contacts are available inside the cabinet
next to the power supply assembly, see figure 2.
These screw terminals are intended for connection
to the customers supervisory alarm or data acqui-
sition system. One set of terminals supplies notifi-
cation of any alarm condition occurring and the
second set of contacts indicate the system is oper-
ating on battery backup power.
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 8
shows this being done using a signal
generator and spectrum analyzer. Record the
measured values for each passband. We rec-
ommend that a 50 ohm load be connected to
the unused RF port on the bottom of the cabinet
during the gain test.
2) The spectrum analyzer is connected to the
-
30
dB signal sampler port following the final output
amp. This port will allow the observation of the
amplifier output at a considerably reduced out-
put level. This decoupling value (-30 dB) needs
to be added to any measured signal value in
order to arrive at the actual signal level.
3) With a spectrum analyzer connected to the sig-
nal sampler port (see
Figure 9
), have person-
nel with handheld radios move to several
Boosted
RF Signal
Signal Distribution System
Spectrum
Analyzer
10 dB Pad
Sample
Sample
Test Port
Test Port
Figure 9
: Methodology for doing a performance survey of the signal distribution system.
