16
the location message will display that fact. In AUTO station selection
the FS700 will display the station location once a station is chosen.
Search Mode
The second screen has two parameters and controls the starting and
stopping of the locking process. The first field controls the SEARCH
MODE. In AUTO search mode the FS700 will automatically begin a
station search any time it is unlocked. In MANUAL mode pressing EXC
will start the search. If a signal error occurs and the FS700 unlocks, the
FS700 will automatically reacquire a station in AUTO mode, while in
MANUAL the lock must be manually restarted. The second field
controls starting and stopping of locking and searches. If the FS700 is
not currently searching or locked, pushing the EXC button will start a
search. If the FS700 is searching or locking, pressing the EXC button
will stop the lock. In AUTO search mode, a new search will
automatically be started once the EXC button is pressed to stop the
search. If manual control is desired, the mode should be set to manual.
Time Constant
The FS700's tracking time constant is set in the third screen in units of
GRI. The time constant is adjusted using the cursor keys, and can be
set between 128 and 16384 GRI. The time constant sets the amount of
signal averaging and the time between corrections of the FS700's
oscillator frequency. The setting is a trade-off between averaging
enough to reduce signal noise, and correcting frequently enough to
correct oscillator frequency changes with room temperature, etc.
Recommended settings are 2048 GRI with the standard oscillator, and
4096 GRI with option 1. If the signal-to-noise ratio of the station being
tracked is poor (< -3 dB), the time constants should be increased by a
factor of two or four. In general, there is no reason to reduce the time
constants below their nominal value.
Keyboard Lock
The menu items that control the FS700's station tracking may be locked
to prevent unauthorized modification. To lock all items in the
TRACKING and CAL menus, enter a password up to 4 digits long.
Entering the password again will unlock the menu items. On power-up
the keyboard lock is automatically cleared. Other features of the
FS700, such as the FREQUENCY OUTPUT and PHASE meter will
operate normally while the TRACKING menus are locked.
Search Mode: Auto
Start Station Acquisition (EXC)
Receiver Time Constant: 4096 GRI
Tracking Keys Lockout: On
Enter Password to Lock Keys:XXXXX
