(7)
Tune HF-1 system to several different channels and ensure operation is good by channeling from both above and below the selected frequency.
NOTE: The tuner duty cycle is 5 minutes on and 5 minutes off on frequencies between 2 to 3 MHz. Excessive keying of system on low frequencies may cause 100°C overheat switch in tuner to fault system; wait 5 minutes and rechannel to reset system. Above 3 MHz the duty cycle is continuous.
(8)
Tune HF-1 system to an authorized test frequency. Key the system and establish communication. Check that the R/T FAULT lamp and KEY INTERLOCK lamp do not come on. Transmission and reception should be loud and clear. Sidetone should be clearly audible when transmitting. The retune cycle shall go to completion with the push-to-talk switch closed.
NOTE: If the R/T FAULT lamp or KEY INTERLOCK lamp comes on or flickers, a defective transceiver or coupler is indicated.
WARNING: DO NOT OPERATE THE HF COMMUNICATION SYSTEM WHILE THE AIRPLANE IS REFUELED OR DEFUELED. AN EXPLOSION CAN CAUSE INJURIES TO PERSONS AND DAMAGE TO THE AIRPLANE.
WARNING: MAKE SURE PERSONNEL STAY A MINIMUM OF 10 FEET (3 METERS) AWAY FROM THE HF COMMUNICATION ANTENNA WHEN THE HF SYSTEM TRANSMITS. RF ENERGY FROM THE HF COMMUNICATION ANTENNA CAN CAUSE INJURIES TO PERSONNEL.
(9)
Repeat steps (1) thru (8) using HF-2 system.
(10)
Secure HF system.
(11)
Determine whether there is any further need for electrical power on the airplane; if not, remove external power.
5E2
23-11-02 Page 502 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. May 01/03
HF ANTENNA AND COUPLER - REMOVAL/INSTALLATION
EFFECTIVITY
AIRPLANES WITH FLUSH ANTENNA
1. HF Antenna - Removal/Installation (Fig. 401)
A. Removal
(1)
On P18 circuit breaker panel, open circuit breakers HF AC and DC.
(2)
Remove screws from antenna access door on leading edge of vertical fin and remove door.
(3)
Remove nut, securing electrical feedline tube to antenna conductor.
(4)
Remove bolts securing antenna (vertical fin leading edge) to aircraft structure, and remove antenna.
B. Installation
(1) Verify that circuit breakers opened in Step A(1) are open.
NOTE: The HF flush antenna includes a fiberglass section on the fin leading edge which is covered with a rain erosion coating. This coating will require replacement, with the frequency of replacement dependent upon the operator's erosion environment.
CAUTION: THE METAL LEADING PORTION OF THE FIN SHOULD NOT BE COATED WITH RAIN EROSION COATING BECAUSE OF LIKELY DETRIMENTAL EFFECTS ON THE HF SYSTEM PERFORMANCE.
(2)
Place antenna into mounting position. Guide antenna conductor into place between electrical straps as antenna is positioned (Fig. 401).
(3)
Align holes in antenna conductor and electrical straps and secure with bolt, washer, and nut.
(4)
Secure antenna to aircraft structure with bolts.
(5)
Install antenna access door.
2. HF Antenna Coupler - Removal/Installation (Fig. 401)
A. Removal
(1)
On P18 circuit breaker panels, open circuit breakers HF AC and DC.
(2)
Remove access door on side of vertical fin (Sta 1016).
(3)
On HF antenna coupler front panel, remove cable connector from J1 and coaxial cable from J2.
(4)
Loosen knurled thumbscrews and disengage from mounting brackets at front of HF antenna coupler.
(5)
Move HF antenna coupler slightly forward until unit is disengaged, then remove HF antenna coupler.
B. Installation
(1)
Verify that circuit breakers opened in Step A(1) are open.
(2)
Slide HF antenna coupler into mount until connector and aligning ring are engaged and seated. Secure with knurled thumbscrews.
(3)
On HF antenna coupler front panel, connect cable connector to J1 and coaxial cable to J2.
(4)
Install access door.
(5)
Close circuit breakers opened in Step A(1).
May 20/82 23-11-61 Page 401
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
H59561
HF Antenna and Antenna Coupler Installation 541
23-11-61 Figure 401 Nov 15/77
Page 402
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
HF ANTENNA AND COUPLER - INSPECTION/CHECK
1. General
A. This procedure does an electrical bond check of the antenna (vertical fin antenna) in the vertical stabilizer.
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