Nautel XL12, Technical Instructions

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12 000 WATT AM BROADCAST TRANSMITTER
XL12
Page 2-32
01 January 2002
(c) Connect an AC voltmeter across the 50 ohm,
10W resistive load connected to the
RF
MONITOR connector.
(d) Set monitor circuit's RF PWR 1 potentiometer
(R26) fully counter clockwise.
(e) Verify a 2-socket shunt post is not installed on
monitor circuit's 3-pin header XE16 (
RF 1
). If
necessary, remove shunt post.
(f) Select highest, series resistance. Short pins 1
and 2 of monitor circuit's 3-pin header XE17
(
RF 1 ). Use a 2-socket shunt post (E17).
(g) If AC voltmeter reading is more than 5.0 volts
RMS or less than 0.714 volts RMS, verify
requirements of steps (a) thru (f) are being
met. Contact Nautel's field service department
if problem persists.
(h) If AC voltmeter reading is between 5.0 and 3.8
volts RMS, adjust
RF PWR 1
potentiometer (R26)
for a reading of 5.0 volts rms.
(i) If AC voltmeter reading is between 3.8 and
2.75 volts RMS:
- Remove 2-socket shunt post E17 from 3-pin
header XE17 (
RF 1 ).
- Short pins 2 and 3 of 3-pin header XE16 ( RF 1 )
using a 2-socket shunt post (E16).
- Adjust
RF PWR 1
potentiometer (R26) for a
reading of 5.0 volts rms.
(j) If AC voltmeter reading is between 2.75 and
1.8 volts RMS:
- Reposition 2-socket shunt post E17 on 3-pin
header XE17 (
RF 1 ) so it shorts pins 2 and 3.
- Adjust
RF PWR 1
potentiometer (R26) for a
reading of 5.0 volts RMS.
(k) If AC voltmeter reading is between 1.8 and
0.714 RMS:
- Remove 2-socket shunt post E17 from 3-pin
header XE17 (
RF 1 ).
- Short pins 1 and 2 of 3-pin header XE16 ( RF 1 )
using a 2-socket shunt post (E16).
- Adjust
RF PWR 1
potentiometer (R26) for a
reading of 5.0 volts rms.
(l) Select preset RF power level 2 (lamp in
RF
POWER 2 switch shall be on); verify the RF
output is the desired forward power level and
then repeat steps (d) thru (k), substituting:
- E18/XE18 ( RF 2 ) for E16/XE16 ( RF 1 ).
- E19/XE19 ( RF 2 ) for E17/XE17 ( RF 1 ).
-
RF PWR 2
potentiometer (R27) for
RF PWR 1
potentiometer (R26).
(m) Select preset RF power level 3 (lamp in
RF
POWER 3 switch shall be on); verify the RF
output is the desired forward power level and
then repeat steps (d) thru (k), substituting:
- E20/XE20 ( RF 3 ) for E16/XE16 ( RF 1 ).
- E21/XE21 ( RF 3 ) for E17/XE17 ( RF 1 ).
-
RF PWR 3
potentiometer (R28) for
RF PWR 1
potentiometer (R26).
(n) Select preset RF power level 4 (lamp in RF
POWER 4 switch shall be on); verify the RF
output is the desired forward power level and
then repeat steps (d) thru (k), substituting:
- E22/XE22 ( RF 4 ) for E16/XE16 ( RF 1 ).
- E23/XE23 (
RF 4
) for E17/XE17 (
RF 1
).
-
RF PWR 4
potentiometer (R29) for
RF PWR 1
potentiometer (R26).
(o) Select preset RF power level 5 (lamp in RF
POWER 5 switch shall be on); verify the RF
output is the desired forward power level and
then repeat steps (d) thru (k), substituting:
- E24/XE24 (
RF 5
) for E16/XE16 (
RF 1
).
- E25/XE25 (
RF 5
) for E17/XE17 (
RF 1
).
- RF PWR 5 potentiometer (R30) for RF PWR 1
potentiometer (R26).
(p) Select preset RF power level 6 (lamp in RF
POWER 6 switch shall be on); verify the RF
output is the desired forward power level and
then repeat steps (d) thru (k), substituting:
- E26/XE26 (
RF 6
) for E16/XE16 (
RF 1
).
- E27/XE27 (
RF 6
) for E17/XE17 (
RF 1
).
- RF PWR 6 potentiometer (R31) for RF PWR 1
potentiometer (R26).