Marti Electronics SRPT-40A User Manual page 26

Next, set the six left-most digits (digits 2-7) of the FREQUENCY SELECT pushwheel switches equal to zero. Then
the far right digit (digit 1) is set to the channel of choice (channel 0 – channel 9) to be stored. After entering the channel,
press the EXECUTE pushbutton down and then release. The current frequency-in-lock will be stored in the selected
channel and the SRPT-40A will remain at its current frequency. If you need to store more channels, repeat the steps in
this paragraph.
Finally, put the S1 dip-switches back to where they were, i.e., switches 1 and 2 in the "ON" position and switches 3
and 4 in the "OFF" position. Re-install the top cover.
It would be a good idea to test the stored channel(s) by changing the frequency to some other frequency and then
recalling the stored channel(s).
Changing the Reference Frequency
The reference frequency setting is usually set such that it is divisible into any operating frequency within your
country's RPU frequency assignment. The reference frequency of the SRPT-40A can be set to either 10.0 KHz or 12.5
KHz. The default reference frequency will be set at the factory according to where the SRPT-40A will be used or
whatever the customer requests.
If you try to change to an output frequency that is not divisible by the set reference frequency, the frequency will not
change. If the output frequency (or frequencies) that you are required to operate at are not all divisible by 10.0 KHz or
12.5 KHz, you may be able to special order a software change to accommodate your required reference frequency.
To change the reference frequency, remove the top cover of the SRPT-40A. The SRPT-40A should be powered on
and locked on a frequency. Set the S1 dip-switches so that switches 1, 3, and 4 are "OFF", and switch 2 is "ON". From
the front panel, adjust the FREQUENCY SELECT pushwheel switches so that digit seven (the left-most digit) is zero;
and digits six, five, and four are 1, 2, and 5 respectively for 12.5 KHz reference frequency or 1, 0, and 0 respectively for
10.0 KHz. It does not matter what pushwheel switches three, two, and one are set to. Now press the EXECUTE
pushbutton down and then release. At this point the output frequency will remain as is and no noticable change will take
place. Re-position the S1 dip-switches such that switches 1 and 2 are "ON" and switches 3 and 4 are "OFF". Re-install
the top cover.
At this point, the reference frequency is only temporarily stored. Therefore, if the power to the SRPT-40A was
turned off and then on, it would revert back to its original reference frequency. The user must therefore change the
output frequency to permanently change the reference frequency.
Control Switch Settings
Control Switch Settings enable or disable important controls used in the SRPT-40A. These control settings include
the following:
Rotary Power Adjust Enable
VSWR Foldback Disable
Reverse Power Calibration Enable
Forward Power Calibration Enable
Hi Temperature Shutdown Disable
Direct Frequency Change Enable
Channel Frequency Change Enable
For changing the setting on any of these controls, it's important to remember that you cannot just change one setting
without updating (or setting) all the other settings at the same time. This is because one command does all. Therefore
you must consider and set all controls at the same time.
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