RADIOBEACON TRANSMITTER
ND500II (125 WATTS) DOUBLE SIDEBAND - NO VOICE
Page 4-10
15 September 2003
Table 4-5 Monitor PWB (A5) Controls and Indicators (Continued)
PANEL MARKING/
REF
FIG
NOMENCLATURE
FUNCTION
DES
NO.
USED IN TEXT
R21
MD-10
FWD PWR
Adjusted, during calibration procedures, to precisely
set the forward power indication on
TEST
meter M1,
when
TEST
switch S6 is set to
FWD PWR
.
R41
MD-10
DELAY
Adjusted to set the continuous period of time
(nominally from 20 to 80 seconds) the carrier level
and/or the modulation percentage must be below their
preset thresholds before the transmitter will shutdown.
R56
MD-10
OVERMOD
Adjusted during calibration, when the transmitter is
operating into a 50.0-ohm resistive load, for a
negative modulation threshold (normally 95%) that
represents the maximum desired modulation
percentage. When the modulation troughs, of the peak
detected RF current sample, fall below this threshold,
the
OVERMOD ALARM
lamp will turn on.
R69
MD-10
SWR THRESH
Adjusted for an SWR fault threshold that represents
the maximum acceptable reflected power before an
SWR cutback output will be produced. When an
SWR cutback output is being produced, the RF
carrier output will be cutback to a level that will
maintain the reflected power at the threshold level and
the
SWR ALARM
lamp will turn on.
R80
MD-10
REFLD PWR
Adjusted to precisely set the reflected power indication
on
TEST
meter M1, when
TEST
switch S6 is set to
REFL PWR
, during calibration procedures.
R89
MD-10
HIGH CARRIER
Adjusted to produce a carrier fault signal when the RF
carrier increases above the desired level (usually by
2.0dB). Ultimately will cause transmitter shutdown if
the RF carrier output does not fall below this
maximum threshold level within the delay period of
the shutdown circuit.
