3.
Radio-system alignment.
a. The radio system alignment is performed after the starting procedures for each radio set of
the system have been made. If connections to the multiplexing system have been made, the control
multiplexing terminal must be informed when the radio-system line-up is completed. Then the overall
system alignment may be accomplished.
b. The radio alignment procedure is accomplished first in the A-B direction, and then in the B-
A direction. When performing the alignment, the controls of the transmitter at radio terminal A are
adjusted first. When this has been accomplished, the control radio terminal attendant directs the
attendant at the next receiver in the A-B direction to adjust his receiver control to obtain appropriate
signal level. When this has been accomplished, radio terminal A then directs that the next transmitter in
the A-B direction be adjusted. Each successive receiver and transmitter in the A-B direction is aligned
in sequence until the receiver at terminal B is aligned. At this point, radio terminal B assumes
temporary control, and directs the alignment in the B-A direction.
4.
Overall system alignment.
The overall system alignment is performed for both the multiplexing system and the radio
system. The alignment is performed at the direction of the controlling multiplexing terminal. As in the
case of the radio system alignment, the multiplexing system alignment is accomplished first in the A-B
direction and then in the B-A direction. The procedure followed is the same at both terminal and
repeater stations as in radio alignment.
Learning Event 2:
NOISE AND INTERFERENCE.
1.
General. The amount of noise or interference at the receiver location limits the length of hops
between multichannel equipment. The more noise or interference that is present, the shorter the distance
that can be covered. A high noise level will reduce quality in telephone circuits and cause errors in
teletypewriter circuits. In the automatic switching system, an excessive noise level can cause trunk call
blockage.
a. Noise in line-of-sight and tropospheric scatter systems. The two basic types of noise existing
within line-of-sight or tropospheric scatter relay systems are:
39
Previous Page
