Installation And Setup; Frequency Setup - BW Broadcast TX5 FM Broadcast Transmitter Technical Manual

2.1

FREQUENCY SETUP

The Frequency can be set on the transmitter in one of two ways:
1. From internal direct reading decimal switches on the main board
2. From the front panel LCD display and front panel buttons.
Many radio regulatory bodies stipulate that the transmitters parameters including the frequency must not be easily
changed from the front panel. To meet this requirement you will need to set the frequency internally with the dial
switches.
The switches have a silkscreen diagram next to them on the board (see diagram below) clearly indicating what
each switch represents.
The top dial switch represents the value selected x 10 Mhz with the exception of '0' which represents 10 so when
selected would equal 100 Mhz.
The second dial switch represents the value selected x 1 Mhz.
The third dial switch represent the value selected x .1 Mhz (100 kHz)
The bottom switch represents the value selected x .0125 Mhz (12.5 kHz)
For example:
FREQ
87.90
98.75
100.00
104.225
108.00
As you can see, the switches directly read the frequency with the
exception of frequencies above 100 Mhz, where the top switch being set at '0'
represents '10'. The X0.125 'offset' switch is only used when you want to pro-
vide a shift to the carrier of between 12.5 kHz and 112.5 kHz. Note that setting
the switch on 8 or 9 will have the same effect as setting the previous switch
(100 kHz) 1 position higher, as 8 represents 100 kHz on the 12.5 kHz switch.
8 x 0.125MHz = 0.1MHz = 100kHz
The LCD display on the front panel will display the frequency that you have set on the internal switches. If you try
to adjust the frequency with the front panel up / down buttons you will get a ' NOT ALLOWED ' message appear-
ing on the LCD display. This protects against unauthorized front panel frequency changes when the frequency
has been set internally with the dial switches.
The TX will load the switch values at power up. You will need to remove the mains power to the transmitter
and then reapply it if you want to change the frequency by using the direct reading switches
LCD front panel frequency selection.
If you want to control the frequency from the front panel LCD con-
trol system you will need to set the internal switches to 4440. The
transmitter will pass frequency control to the LCD control system
and the frequency can be moved up and down by pressing the
NEXT button until the frequency menu is displayed. The other two
buttons control the UP and DOWN frequency selection. PLL lock
status is also displayed on this screen.
The LCD readout will only display frequencies in 100Khz steps. Any frequency offsets derived from the
internal 12.5kHz offset switch will not show on the LCD. Consult a frequency counter if using offsets.
BW Broadcast technical manual
SWITCHES (MHz)
X10 X1 X.1
'8' '7' '9'
'9' '8' '7'
'0' '0' '0'
'0' '4' '2'
'0' '8' '0'
X.0125
'0'
'4'
'0'
'2'
'0'

Installation and setup

Frequency selection switches on main board
Note that some pcb's have "set to 4444 for
front panel LCD control". This is an error that
will cause a +50kHz offset to the frequency set
on the LCD screen. Please set to 4440 unless
you specifically want the offset.
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