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5. Channel Lockouts: Channel Lockouts are used to instruct the scanner to skip over
specified menu channels during searches for activity in the MScan mode.
6. Frequency Lockouts: Frequency Lockouts are used to eliminate scan interruptions
caused by unwanted signals. The Frequency Lockout has two components: 1.) a Lockout
Center, and 2.) the Bandwidth Attribute. The Lockout Center is determined by the
receiver's operating frequency at the time of the lockout entry. The Bandwidth Attribute
is determined by receiver's selected bandwidth (BW). Together, these parameters
establish the Frequency Interval that will be skipped on subsequent scans. To calculate
the boundaries of the Frequency Interval, use the formula:
Interval = (Center) ± 1/2 (Attribute)
To illustrate how frequency lockouts work, suppose WWV at 10 MHz disrupts a scan
searching for intermittent push-to-talk signals. Now, suppose the receiver's bandwidth is
set at 10 kHz:
Entering the Lockout command while the receiver is paused on the unwanted station will
automatically program a 10.000-MHz Lockout Center and a 10-kHz Bandwidth Attribute
into the PScan memory. As a result of this entry, when scanning resumes, the Frequency
Interval between 9.995 MHz and 10.005 MHz will be excluded on future passes—
eliminating the interference problem.
Important Note: When initiating a new PScan setup, it's usually advisable to clear all
previous lockouts from memory and start with a clean "slate". All lockouts and channels
are cleared when the receiver is reset (See section 4-37).
4-35 TO SETUP A PSCAN (PROGRAMMED F
→ F
) FREQUENCY SWEEP:
1
2
The PScan mode is used to search all frequencies between a specified Start frequency
(F1) and an End frequency (F2). F1 is the lower frequency in the search, and F2 is the
higher.
To enter the Scan Setup mode, clear any other scan functions and press the Setup button.
It will light and the 'Select Scan Type' message will appear:
4-20
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