(8) AF GAIN The AF GAIN control varies the volume level from the speaker. Clockwise rotation increases the volume level.   (9) TONE This control varies the high-frequency audio response. The variation in audio fidelity provided by the TONE control is highly useful in minimizing interference from heterodynes and other high pitched noises that might ruin reception.   (10) S-METER The S-meter provides a relative indication of the signal strength on the incoming signal. The upper scale is calibrated in S-units from S1 to S9, with stronger signals indicated in dB over S9. The lower scale is calibrated in S-units compatible with the SINPO code, as shown in Table 1.   (11) AM, PM These are AM and PM indicators for the clock.   (12) MAIN DIAL The main dial determines the operating frequency of the FRG-7700, in conjunction with the setting, of the BAND switch.   (13) DIGITAL DISPLAY The digital display indicates the operating frequency as well as the time. Selection of display of the frequency or time is made via the FUNCTION switch.   (14) ATT The ATT (Attenuator) control, when rotated in a clockwise direction, reduces the gain of the receiver preamplifier, thus minimizing overloading of the receiver during conditions of extremely strong adjacent-frequency interference. Maximum receiver sensitivity occurs when the ATT control is rotated to the fully counterclockwise position.   (15) M FINE This control allows fine tuning during memory operation. A frequency excursion of up to l kHz. HOUR may be achieved using this control.   (16) SQL The SQL (Squelch) control will silence the receiver until a signal is received. The SQL control is usable ONLY in the FM mode.

(17) CONTROL SWITCHES (TIMER, DIM, M, MR) TIMER Once the desired on/off timers are programmed into the clock, push this switch to activate the power control timer. In this mode, the digital clock timer will turn the receiver on and off. DIM This button. when pushed, will allow dimming of the meter lamp, the dial lamps, and the display intensity. M Push this button to store a frequency into memory. MR This button, when pushed, transfers frequency control from the main dial to the memory system. Push the button again to return to main dial tuning.   (18) BAND This switch selects the desired 1 MHz segment within the HF spectrum, with calibrations from 0 MHz to 29 MHz. Also provided are preset marks for the HF amateur radio (ham) bands.   (19) M CH This switch selects the desired memory channel.   (20) FUNCTION This switch selects the Digital Display functions. FREQ All digits of the operating frequency are displayed with resolution to 1 kHz. CLOCK Time is displayed in a 12-hour format. ON The ON time, at which the receiver will be turned on, is displayed. OFF The OFF time, at winch the receiver will be turned off, is displayed. SLEEP The remaining time of the sleep timer is displayed. (Up to 59 minutes can be set for the sleep timer.)   (21) CLOCK SETTING SWITCHES HOUR This switch is used for setting hours on the clock and timer. Pressing this switch once will advance the reading by one hour. If this switch is held for more than two seconds, the hour reading will advance continuously.