Marti Electronics SRPT-30 User Manual page 33

Changing Output Frequency Direct
SRPT-30 Only:
Simply change the position of the F1/F2 front panel switch and the unit will change to the corresponding frequency.
SRPT-40A Only:
To change the frequency of the SRPT-40A, the S1 dip-switches on the Front Panel Control & Meter board (800-
385A) behind the front panel (see the SRPT-40A Adjustment Locations) need to be set with switches 1 and 2 in the
"ON" position and switches 3 and 4 in the "OFF" position. These positions are the normal position and are set at the
factory, so there should be no need to remove the top cover.
When the S1 switches are set as described in the last paragraph, then all that is required is to enter the desired
frequency from left to right into the FREQUENCY SELECT pushwheel switches and then press and release the
EXECUTE pushbutton switch.
All seven digits on the front panel FREQUENCY SELECT pushwheel switches must be entered. The frequency is
entered in MHz where the first three digits represent the left side of the decimal place, and the last four digits represent
the right side of the decimal place. For example, the frequency 450.0125 MHz will simply be entered as 4500125.
If a valid frequency is entered and the EXECUTE pushbutton is pressed and released, then the RF output power will
immediately turn off (if it was on to begin with) and the SYNTHESIZER will go through it's normal routine in searching
and locking onto the requested frequency. When the frequency is found, the AFC LOCK LED will stop flashing and
illuminate solid green. After three seconds the TRANSMIT LED will stop flashing and illuminate solid red (assuming
the TRANSMIT/STANDBY switch is in the TRANSMIT position) and the SRPT-40A will resume transmitting at the
new frequency and at the same output power it was before leaving the previous frequency.
What is A Valid Output Frequency?
A valid output frequency is defined as a frequency that operates within the model bandwidth and is either a standard
frequency, or is a non-standard frequency that falls within ±.00015% of the requested frequency. A standard output
frequency is one that is divisible by 5 or 6.25 KHz for 450 band models and less, and divisible by 10 or 12.5 KHz for
greater than 450 band models. All other frequencies are considered non-standard frequencies. The SRPT-30/40A will
lock on standard output frequencies within a ±.00004% tolerance. The SRPT-30/40A will lock on about 95% of non-
standard frequencies. The tolerance of these frequencies fall within ±.00015% of the requested frequency. If the
synthesizer determines that the non-standard frequency will fall outside ±.00015% of the requested frequency, then this
is considered an invalid frequency and it will not change to the requested frequency.
SRPT-30 Only:
There are only two frequencies to choose from, F1 and F2, as configured at the factory, and are always considered
valid. However, at the time of order, if the customer requires a frequency that is not divisible by 5 or 6.25 KHz (or by 10
or 12.5 KHz for > than 450 MHz models), we can determine immediately whether or not the requested frequencies will
fall within ±.00015% tolerance. If one or both frequencies do fall not within this tolerance, then the order will be
considered special and must be determined by the engineering department at Broadcast Electronics if we can tune to the
required frequencies.
SRPT-40A Only:
If an invalid frequency is entered in, or if the same frequency that the SRPT-40A is currently locked on to is entered
in, then the SRPT-40A will remain at its current frequency, i.e., nothing will happen. If the operator desires to change to
a frequency that is invalid, he must choose the closest valid frequency and then manually tune the reference oscillator on
the synthesizer to get to desired frequency. However, if the operator tunes the reference oscillator to get to an invalid
frequency, then when needing to change to another frequency (valid or non-valid), the operator may have to retune the
reference oscillator again.
8/7/2003
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