Broadcast Warehouse TX 25/50, Техническое руководство

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TX25/50 FM Transmitter technical manual
page 8
Installation and setup
2.2 R.F. POWER SETUP
The R.F. power output from the transmitter can be controlled by an analogue potentiometer (POT) or from the
front panel LCD screen or a combination of both.
ANALOGUE POWER CONTROL
If the frequency is set internally with the dial switches you will not be able to adjust the power from the LCD
screen. This is to comply with regulatory body’s that stipulate that the transmitter is not to have it’s parameters
adjustable from the front panel. In this case you must use the maximum power set control to set the transmitters
power. This control will give the full power range adjustment.
If the transmitter has been internally set to 4440 with the dial switches then you can also control the power from
the LCD screen’s R.F. power menu’s up and down buttons. A “not allowed” message will be displayed to the user
if the dial switches are not set to 4440
RS232 power control will over-ride the power control restrictions caused by having the frequency set
internally (not set to 4440).
DIGITAL POWER CONTROL
When the power is to be controlled from the front panel the max power set POT takes on a new role of setting the
maximum power of the transmitter. If you want the LCD screen to have full power range control of the transmitter
you will need to ensure that the max power set control is at maximum power. Otherwise your control range may
be limited. This feature enables you to limit the transmitters maximum power to a fixed level but to still allow the
LCD screen to provide adjustment of the R.F. power down from that maximum power set point. This can be desir-
able in transmitter hire situations where you wish to govern the maximum
output to a fixed level but to allow the customer (hirer of the transmitter) to
run the power of the transmitter at a lower level if they so decide.
The maximum power set is positioned to the lower left of the LCD screen on
some models, other models may not have the hole in the front panel and you
will need to remove the lid of the transmitter to access the adjustment which will be in the same position but on
the other side of the PCB. You will need a small ‘tweaker style’ flathead screwdriver to adjust the pot. This control
is quite delicate so try to not be too heavy handed in it’s adjustment.
Please note that the VSWR and temperature protection circuitry will turn back the R.F. power if a fault con-
dition exists. Make sure that you have a good VSWR (low reverse power reading) before setting the R.F.
power as the removal of a fault condition may cause the R.F. power to increase.
RF POWER MUTE (analogue)
There is a pin (8) on the back panel D-type that can be pulled low to mute the
transmitters RF power. The RS232 interface board also has a connection to mute
the RF this way. Consult the RS232 section of this manual for more information.
RF POWER MUTE (digital/RS232)
The transmitters RF power output can be muted via the RS232 control system.
Terminal software can mute/unmute the RF power with the ‘o’ and ‘f’ commands
respectively.
The windows application has a button that can toggle the RF output of the trans-
mitter.
please consult the RS232 section of this manual for more information on controlling the transmitter remotely.