Operation of the FRG 7700 is extremely straightforward. However, the owner should read the pages to follow carefully so as to derive maximum performance from this equipment. Before attempting operation, make certain that all power, antenna, and ground connections have been made correctly.
The operating frequency is read directly from the digital display. All digits of the operating frequency are displayed, with resolution to 1 kHz. The BAND switch is calibrated in 1 MHz steps, from 0 MHz through '_9 MHz, with an additional 10 steps being provided for instant presetting to the bands containing the amateur radio (ham) bands.
To select a frequency, first set the BAND switch to the desired 1 MHz segment, then rotate the main dial to select the last three digits of the frequency. A coarse frequency determination may also be made through the main dial window, which is calibrated every 10 kHz.
(1) Virtually all commercial broadcast stations in the MF and FIT bands use the AM (Amplitude Modulation) mode of operation. To begin, turn the power switch on, and set the mode switch to AM M (AM mode, medium bandwidth).
(2) Tune in an AM station to the point where the S meter reading reaches a maximum.
(3) If there is very heavy interference, you may wish to set the mode switch to the AM N (AM mode, narrow bandwidth) position. Thin will provide maximum rejection of adjacentfrequency interference. although the narrower bandwidth will cause some rejection in fidelity. Conversely, if there is very little interference, you may switch to the AM W (AM mode, wide bandwidth) position. This will provide maximum fidelity because of the wider bandwidth.
(4) The TONE control on the front panel may be used to vary the audio response characteristics of the receiver. For example, if you are troubled by a high pitched "heterodyne" signal, rotate the TONE control in a counterclockwise direction to reduce this interference .
(5) When extremely strong signals are encountered. the operator may want to reduce the level of these signals. Rotate the ATT (At control on the front panel clockwise to reduce the strength of the incoming signals. Should you desire to activate a fixed 20 dB attenuator set the rear panel ATT switch to LOCAL. For most listening, though, leave this switch set to the DX position.
(6) For reduction in impulse type noise (automobile ignition, etc.), push the NB (Noise Blanker) switch. This circuit is highly effective in minimizing this type of interference, although no noise blanker can be expected to eliminate all types of noise.
(7) An Automatic Gain Control (AGC) circuit is included in your FRG 7700. This feature keeps signal strengths adjusted to a constant level under conditions of fading. When rapid fading conditions are encountered, you may want to set the AGC switch to FAST, as the use of the SLOW position might cause a weak signal to be obliterated by an adjacentfrequency station which is much stronger. With some experience, the operator will soon learn the proper settings of the MODE and AGC switches for operation under a variety of conditions.
Amateur radio operators use a variety of operating modes on the HF bands. However, your FRG 7700 is well equipped to receive the various types of ham signals encountered in day to day operation.
SSB Voice Signals
(1) Amateur radio operators use lower sideband (LSB) 1 on the bands below 10 MHz, and upper sideband (USB) above 10 MHz. Set the mode switch accordingly.