RADIOBEACON TRANSMITTER
ND500II (125 WATTS) DOUBLE SIDEBAND - NO VOICE
Page 4-7
15 September 2003
Table 4-3 Keyer PWB (A3) Controls and Indicators
PANEL MARKING/
REF
FIG
NOMENCLATURE
FUNCTION
DES
NO.
USED IN TEXT
DS1
MD-8
KEYER FAULT
Indicates a problem has occurred with one or both
EEPROMs on the keyer PWB. Action taken on the
transmitter is dependent on the setting of the
ENBL/DSBL
jumper (E4).
E1/E2
MD-8
400/1020
Shunt posts that determine the keyed tone frequency of
the keyer PWB.
Installed to short pins 1 and 2 for 1020 Hz.
Installed to short pins 2 and 3 for 400 Hz.
E3
MD-8
INT/EXT
Shunt post that determines the keyed tone source.
Installed in
INT
position (shorting pins 1 and 2) for an
internal tone oscillator.
Installed in
EXT
position (shorting pins 2 and 3) for an
external oscillator.
E4
MD-8
ENBL/DSBL
Shunt post that determines the action taken when a
keyer fault occurs.
When installed in the
ENBL
position (shorting pins 1
and 2), the fault inhibits the
keyed tone
output. A
continuous tone will be generated when this occurs.
When installed in the
DSBL
position (shorting pins 2
and 3), the fault, although indicated by
KEYER FAULT
lamp DS1, has no effect on the
keyed tone
output.
S1 – S4
MD-8
Keyer Setup Switches
Pushbutton switches S1 (up), S2 (left), S3 (right) and
S4 (down), and alphanumeric displays U11 through
U14, are used to configure the keyer’s contents (type,
characters, standby ‘1’ code, frame type and frame
length). Pressing S2 and S3 simultaneously enters the
setup menu. This menu is used to set up all aspects of
the keyer. To navigate the setup menu, S1
increments, S4 decrements, S2 backs up, and S3
accepts and proceeds to the next selection.
U11 – U14
MD-8
Keyer Content Display
Alphanumeric displays that, during normal operation,
indicate the keyed characters (after setup, display in-
active until a pushbutton switch is pressed). In
conjunction with switches S1 through S4, the displays
are used to set up/change the keyer contents. When
all characters display a ‘
!
’ character, a fault exists
with the keyer PWB’s EEPROM(s).
