It should be noted the receiver is already factory aligned to open squelch at 12dB SINAD and close
at 8dB SINAD.
Fine-tuning Transmitter Alignment
In order to fine-tune the transmitter alignment, you’ll need to find the optimal value of each of the six
parameters listed on the previous page. For this process, you’ll need a VHF/UHF service monitor capable of
duplex operation. Follow the steps below:
1) Start the alignment procedure
Once the repeater has powered up and it is on the selected channel that you wish to fine tune, press and hold the AUX
button for approximately two seconds. The LCD will display DEFAULT and the TX LED will be illuminated. Press and release
the BASE button. AL-GAIN will be displayed. To cycle through the available alignment parameters, press the BASE button
repeatedly.
2) Set up the service monitor
Set the service monitor to duplex mode. For 25 kHz channel spacing (wide band), generate a 1 kHz tone at 3 kHz deviation
on the receive frequency. For 12.5 kHz channel spacing (narrow band) generate a 1 kHz tone at 2 kHz deviation on the
receive frequency. The signal strength of the tone should be a reasonable level for the receiver to pick-up. With sufficient
carrier, the yellow RX LED will illuminate.
3) Adjust the TX-FREQ parameter
Select TX FREQ in the alignment menu. With the receiver quiet, place the service monitor on the transmit frequency.
Adjust the TCXO voltage by pressing the up and down buttons to the point where the transmitter is on frequency as close as
possible.
4) Adjust the AL-GAIN and AL-AMP parameters
Select the AL-GAIN and AL-AMP parameters by cycling through the available alignment parameters as described in Step 1
above. Adjust the AL-GAIN and AL-AMP parameters by pressing the up () and down () buttons on the keypad. Adjust
these parameters for the best sounding level. The effect of stepping through these settings is to be observed on the service
monitor.
The CS-540’s built-in limiter will keep the transmitter from overdeviating by more than 5 kHz for 25 kHz channel spacing
(wide band) and by more than 2.5 kHz for 12.5 kHz channel spacing (narrow band).
5) Adjust the SUB DEV parameter
Select the SUB DEV parameter in the alignment menu. Using the service monitor in duplex mode, send to the receiver a
full-quieting signal with a tone or code the repeater is programmed to decode. Once the repeater has decoded the sub
audible signal, the transmitter will begin sending the programmed tone or code. Using the service monitor’s deviation
meter, adjust the sub-audible deviation by pressing-and-releasing the UP () and DOWN () buttons to achieve the
desired level.
6) Adjust the TX-DEV parameter
Select the TX-DEV parameter. Inject a 1 kHz tone at 3 kHz deviation along with the programmed sub-audible tone or code.
Once the repeater has decoded the sub-audible and the transmitter is engaged, use the service monitor’s deviation meter to
adjust the over-all transmit deviation level. Once the desired level is achieved, it is recommended you test the settings by
using a hand portable or mobile to communicate through the repeater. If necessary, repeat the above steps to achieve the
best performance.
7) Adjust the TX-PWR parameter
Select TX PWR in the alignment menu. With the receiver quiet, press-and-release either the up or down button to engage
the RF power amp. Using the service monitor, observe the output power level. The transmit power level is factory set for a
low power of 5W and a high power of 40W. Depending on whether the CS-540 was programmed for low power or high
power, this setting should be around 5W or 40W respectfully. Adjust the power to the level required by simply pressing-
and-releasing the up or down buttons until the desired output power level is achieved. The RF Power Amp is disengaged
when the AUX button is pressed.
8) Exit
Pressing the AUX button will exit the alignment mode and restore the CS-540 to repeater mode. The new settings should
be tested to the satisfaction of the system operator.
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