Shortwave Reception
From the example of the shortwave receiver NRD-535, I will guide you how to operate a contemporary shortwave communication receiver with it's most important controls and functions.
There have been some guidebooks usually given away with the purchase of a „world receiver“, here you might find additional information:
- Der Kurzwellenempfang, Grundig - Deutsche Welle, german - english
Note that not all receivers are equipped with all features mentioned, the simpler receivers with fewer options and knobs are easier to operate.
Before starting with reception experiments, the receiver must be supplied with current from the mains or batteries (take care that your set matches the voltage used in your country, in Europa 230 V, which is far too much for U.S. set with the voltage selector in the original 110 V setting). In addition, a RF signal must be supplied by means of a suitable antenna.
With some receivers, you only have to pull out the telescopic antenna; professional receivers usually require an outdoor aerial. For the first attempts, some meters of insulated wire connected to the terminal „long wire antenna“ should do the job.
1: The power switch or mains switch is used to switch on the receiver, a third position activates the timer mode.
2: On semi-professional and professional receivers, the volume control is often labelled AF-Gain (Audio frequency).
2a: The volume control marked RF-Gain (Radio frequency) is used to adjust the high-frequency amplification. Especially when long-wire antennas are used, that supply high signal voltages, overloading of the receiver's input stage can lead to overload symptoms that are noticeable as „crackling“ and „clattering“.
In this case, and in the case of „ghost stations“ appearing as unwanted signals on unwanted spots on the dial in the presence of very strong signals from nearby transmitters, the signal can be attenuated with the RF gain or with the attenuator (ATT) button, and the phenomena might disappear.
Caution: in normal operation, the RF gain must always be be turned to the maximum setting; if it is turned down inadvertently, nothing will be heard from the loudspeaker even when receiving a medium strength signal. In some sets, the signal-strength meter will go up to middle or maximum position when you have reduced the RF gain.
Caution: with some receivers, the automatic RF gain control (AGC) is switched off when the RF gain control is activated. In manual mode you have to control the RF amplification carefully by hand to avoid distortions caused by strong signals.
3: The frequency can be selected with the main tuning knob, with many receivers the tuning step width and thus the tuning speed can be switched. The maximal still acceptable tuning step for AM reception is 1 kHz, better would be 0.1 kHz. For SSB reception steps should be no more then 40 - 50 Hz to avoid heterodyne tones, some station receivers already have 1 Hz tuning steps.
The rotary tuning knob should have a certain weight for flywheel effect, run smoothly and tuning should react without mechanical backlash. Some receivers have a brake to adjust the resistance of the tuning knob, in others, a too light tuning knob can be improved by glueing small lead balls in the interior of the knob to give it a certain weight and tuning feeling. Few commercial receivers only provide up/down tuning buttons, some rare models use decadic switches to set the reception frequency.
4: With the decimal key pad a desired reception frequency can be entered directly, pushing the „Enter“ button will bring you immediately to the desired frequency. Some receivers, for example some Lowe sets or the AOR 7030, use a remote control for direct frequency input.
At least a hiss should now be audible from the speaker.