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16
TXMGC
ON = Manual gain control, OFF = Software control or at default setting
TX
– 0.5dB ON = Gain increased by 0.5dB nominal, OFF= no gain increase
TX
– 1dB
ON = Gain increased by 1dB nominal, OFF= no gain increase
TX
– 2dB
ON = Gain increased by 2dB nominal, OFF= no gain increase
TX
– 4dB
ON = Gain increased by 4dB nominal, OFF= no gain increase
TX
– 8dB
ON = Gain increased by 8dB nominal, OFF= no gain increase
When MGC is not in use, manual attenuation has to be set to zero, i.e. all poles with the same switch
should return to OFF position. Failure to do so may prevent the module from controlling the gain
correctly.
2.4.2.3 Manual gain control example
In this example we consider a receiver. The factory set values will typically be in the mid-range of the
allowable gain setting range, to allow the operator to both increase and decrease the gain of the unit if
desired.
Factory preset: TX
–0.5dB =ON; TX–1dB =OFF; TX–2dB =ON; TX–4dB =ON; TX–8dB =OFF.
This is a total gain of 0.5 + 2 + 4 = 6.5dB [this will be the factory preset gain]
The operator wishes to increase the gain by 3dB from factory preset gain, he must increase the DIP
switch set gain from 6.5dB to 9.5dB
The new gain setting desired will be 9.5dB, made from the following steps 0.5 + 1 + 8, therefore
set the switches as shown below
TX
– 0.5dB = ON; TX – 1dB = ON; TX – 2dB = OFF; TX – 4dB = OFF; TX – 8dB = ON.
The new gain is now set to 9.5dB
Note: The gain of the link is the sum of the transmitter module and receiver module gains.
2.4.2.4 DIP switches - control
If you wish to use manual control we advise that you record the initial setting of each switch, this is the
preset configuration of the module. SW3 control functions are common to the whole module. The on-
board micro controllers can be manually reset by using TX_RESET and/or RX_RESET, they must
return to the OFF (clear) position to initiate the actual reset sequence.
Switching on SNMP_dis will disable the module I2C bus for that module. In this case, SNMP
controller or other I2C hosts will be unable to talk to the module.
RF auto gain control (AGC) function can be activated by setting TX_AGC_ON and RX_AGC_ON to
ON (set) position. However, AGC mode will be overridden by MGC mode if both modes are selected.
These will override module internal soft gain control. Some modules will have control functions
indicated that are not used, such as RX_rst
in a single transmitter module. Switches for these “not
used” positions should always be left in the OFF (clear) position.
TX rst
Reset TX microcontroller by moving switch from OFF > ON > OFF, ensure that it is
returned to the OFF position**
RX rst
Reset RX microcontroller by moving switch from OFF > ON > OFF, ensure that it is
returned to the OFF position**
SNMP_dis ON = I2C bus disabled (module cannot be remotely accessed), OFF = I2C bus
enabled
Tone
ON = 22kHz tone present, OFF = 22kHz tone disabled
VSEL
ON = Internal module LNB PSU voltage set to 18V, OFF = Internal module LNB PSU
voltage set to 13V
LNB
ON = Internal module LNB PSU enabled, OFF = Internal module LNB PSU disabled
TXAGC*
ON = TX AGC control function activate, OFF = TX AGC control function disabled
RXAGC*
ON = RX AGC control function activate, OFF = RX AGC control function disabled
* Not available on manual control modules
