Nautel XL12, Technical Instructions

Page: 28 / 238

12 000 WATT AM BROADCAST TRANSMITTER
XL12
Page 2-4
01 January 2002
2.1.6.1.2
When two audio sources are used, they
are both connected to terminals on the remote
interface PWB. Exciter A's audio must be
connected between TB2-8(+) and TB2-9(-). Exciter
B's audio must be connected between TB2-11(+)
and TB2-12(-). The exciter interface PWB's
AUDIO
SOURCE
switch must be set to
DUAL
.
2.1.6.2 Both Exciters AM Stereo (External RF
Drive):
When both exciters are configured for AM
stereo operation and the RF drive is being produced
by an external AM stereo generator, the L+R audio
from the AM stereo generator must be considered as
a single source and connected between TB2-8(+)
and TB2-9(-) of the remote interface PWB. The
exciter interface PWB's
AUDIO SOURCE switch must
be set to SINGLE .
The audio must:
-
be a balanced 600 ohms.
- have an output level which is between 0dBm
and +12dBm for 100% modulation.
- contain the left plus right (L+R) audio
information required for AM stereo.
2.1.6.3 One Exciter AM Stereo (External RF
Drive)/One Exciter Monaural:
When only one
exciter (either) is configured for AM Stereo
operation using an external AM stereo generator as
the RF drive source, the other must be configured for
monaural operation using its integral RF drive. The
left plus right (L+R) audio from the AM stereo
generator and a monaural audio must be used and
connected to the appropriate exciter's audio input
terminals on the remote interface PWB [exciter 'A'
audio to TB2-8(+)/TB2-9(-)/exciter 'B' audio to TB2-
11(+)/TB2-12(-)]. The exciter interface PWB's
AUDIO SOURCE
switch must be set to
DUAL
. The audio
inputs must:
- be a balanced 600 ohms.
- have an output level which is between 0dBm
and +12dBm for 100% modulation.
- The audio for the AM stereo exciter must
contain the left plus right (L+R) audio
information.
2.1.6.4 Exciter 'A' AM Stereo (Optional C-
QUAM AM Stereo Exciter as RF Drive
Source:
When the optional C-QUAM AM stereo
exciter PWB (A2A2) is installed as exciter A's RF
drive source, exciter 'B' may be configured for AM
stereo or monaural operation from an external RF
drive source or for monaural operation from its
integral RF drive. Exciter A's left and right audio
must be applied directly to terminals on the C-
QUAM AM stereo exciter PWB [left audio to TB1-
5(+)/TB1-3(-) and right audio to TB1-10(+)/TB1-8(-
)]. The audio for exciter 'B' must be connected
between TB2-11(+) and TB2-12(-) of the remote
interface PWB. The exciter interface PWB's
AUDIO
SOURCE
switch must be set to
STEREO
.
All audio inputs must be a balanced 600 ohms.
Exciter A's left and right audio output levels must
both be +10dBm for 100% modulation (left plus right
channel).
Exciter B's audio output levels must be between
0dBm and +12dBm for 100% modulation.
2.1.7 SAFETY INTERLOCKS:
There are
three types of safety interlocks, one mechanical and
two electrical. The mechanical interlock is a key
controlled system that locks the rear door and
prevents access to areas with high voltages when
AC power is being applied. One of the electrical
interlocks is an external circuit that inhibits the RF
output if any of its serially connected switches is
opened. The second electrical interlock is an internal
circuit that prevents the RF output from being
enabled if the ground wand has not been returned to
its retaining clips after use.
2.1.7.1 External Electrical Interlock:
The
external electrical interlock circuit is connected
between TB1-26 (
+24V INTLK
) and TB1-25 (
INTLK
OPEN ) of the remote interface PWB. When it is safe
to produce an RF output, the circuit must be intact
and apply +24V to TB1-25 (
INTLK OPEN ). When it is
not safe to produce an RF output (one or more of the
external interlock switches have been activated), the
circuit must provide an open circuit to TB1-25 (
INTLK
OPEN
). Any number of serial interlock switches may
be installed, pr24V is removed from TB1-25
if any interlock switch is activated.