Electroline Control Unit IV - Table 6-2: Procedures for Troubleshooting Problems with the RF out Port

Troubleshooting Control Unit IV Reference Manual
6-4 529-0004 Ver.3
To check the RF signal output:
a. Connect the output of the Control Unit’s
RF OUT
(or
TEST OUT
) connector to the
spectrum analyzer’s input.
b. Set the spectrum analyzer’s resolution bandwidth to 10 kHz.
c. Set the span to 2.0 MHz.
d. Set the center frequency to the nominal value in MHz of the Control Unit’s carrier.
e. Center the control carrier(s) displayed.
f. Set the span to about 1 MHz.
g. Check the values displayed on the spectrum analyzer. If the signal’s amplitude is not
48 dBmV ±1 dB for Control Units producing a dual FSK carrier, or 51 dBmV ±2 dB
for Control Units producing a single FSK carrier, or if the carrier(s) are not present,
refer to the troubleshooting procedures in Table 6-2 when measuring the
RF OUT
port,
or Table 6-3 when measuring the
TEST OUT
port.
Table 6-2: Procedures for troubleshooting problems with the RF OUT port
Signal ok on
RF OUT
?
FSK LED
on or off?
Action
Yes On None. No troubleshooting required.
No Off 1. Make sure you are measuring the signal on the
master unit (see note on next page).
2. If you are sure that there is no signal on the master
unit’s RF output, switch to the backup unit, if there
is one, and contact Electroline’s technical support
department. This situation requires immediate
service since the addressable taps are not receiving
status messages from this Control Unit.
Yes Off 1. Make sure that the spectrum analyzer is centered on
the Control Unit’s nominal frequency. Note that
single-FSK modulators are frequency-agile and may
be programmed incorrectly. Check the frequency
and refer to Chapter 5 to reprogram the Control
Unit to the correct frequency.
2. Make sure that the jumper on the
RF IN
port and the
RF OUT
port is properly connected.
3. Measure the signal on the
TEST OUT
port. See step 6
for instructions.