500 WATT RADIOBEACON TRANSMITTER
ND2000A-02X-xx0
Page
3-7
15 January 2005
(b) A link must be connected between printed
wiring pad
A
and pad
B
(enables crystal
controlled oscillator).
(c) A link must not be connected between printed
wiring pad
D
and any other pad (disables
buffer/isolation amplifier).
(d) A link must not be connected between printed
wiring pad
F
and any other pad.
(e) A link must be connected between printed
wiring pad
E
and the appropriate divide-by pad
(
/
4
,
/
8
or
/
16
). Enter table 3-1 with carrier
frequency to determine divider.
3.9.3
KEYER PWB PRE-INSTALLATION
:
Complete the pre-installation procedures on keyer
PWB A3 as follows (refer to figure MD-14 to locate
the keyer PWB and to figure MD-17 for its assembly
detail):
3.9.3.1 Keyer
Content
Configuration:
Set up the
keyer’s content (type, number of characters, standby
code, character setting and frame length) as follows:
NOTE
The keyer PWB’s pushbutton switches S1 (up), S2
(left), S3 (right) and S4 (down), in conjunction with
four alphanumeric displays, are used to configure
the keyer’s contents. 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.
(a)
Enter the keyer’s setup menu by pressing S2
and S3 simultaneously.
(b)
Select the keyer type, as indicated by the
alphanumeric displays, noting the options are
ICAO
or
TRAN
. If
TRAN
is selected, proceed to
step (e), otherwise continue to step (c).
-
ICAO
(International Civil Aviation
Organization) is a standard that allows the
user to key any number of symbols (in this
case, 1 to 4) using a variable bit/frame length
(5 to 16 second frames). Standby code 1
inserts a space between predetermined letters
when it is held low. When standby 2 is
grounded, a blip is inserted before the first
letter is keyed.
-
TRAN
(Transport Canada) uses a 10-second
frame and 0.125ms bits to key out 3 symbols.
When the standby 1 pin is held low, the space
after the last letter and before the continuous
tone is extended from 5 spaces to 9. When
standby 1 and 2 pins are both held low,
standby 1 is alternated. One frame will have
the elongated space and the following frame
will have the shorter space.
NOTE
The
KEYER FAULT
lamp (DS1) may turn/be on
during keyer setup. It should turn off when the keyer
is configured.
If an exclamation point
(
!
)
is displayed on the
alphanumeric displays during keyer setup, an
EEPROM error may exist.
(c)
For
ICAO
keying only, select the number of
letters to be keyed, noting the options are
1
,
2
,
3
or
4
.
(d)
For
ICAO
keying only, set up standby code '1',
noting the options are
1
,
2
,
3
or
4
[depending
on number of characters selected in step (c)],
signifying the character that precedes the
space.
(e)
Set up each of the eight output frames by
selecting the frame type, noting the options are
keyed (
k
), mark (
M
) or space (
S
).
