Raytheon NSC 18 User Manual page 44

The tip of the tuning bar (yellow color) remains at the peak signal detected
during one complete revolution of the antenna.
Bear in mind the fact that the transmitter frequency will drift for the first thirty
(30) minutes of operation from a cold start due to inherent magnetron
characteristics. As a result of this, the receiver tuning will change during this
time and a final tuning adjustment should be made after approximately thirty
(30) minutes of operation. The tuning should also be checked at four−hourly
intervals thereafter.
When auto tuning is activated, manual tuning is not available. The slider symbol
is hidden and the tuning bar color changes to yellow.
Auto tune is only available if the NSC radar is working in Master mode.
With automatic receiver adjustment, the tendency indicator adjusts itself to
the maximum value.
− If the magnetron is at the end of its service life and the transmission
3748DOC020102
Operator Manual
AUTO TUNE (only available in Master mode)
spectrum has become abnormal, select manual tuning.
NOTE
NOTE
2−26
Edition: 14.JAN.2005