Realistic DX-394 Shortwave Receiver

Introduction

The Realistic DX-394 allows you to listen to radio broadcasts from countries around the world. It features 13 international shortwave (SW) bands, reception of amateur radio broadcasts (SSB and telegraphy CW), and long and medium wave bands (LW and MW) for European broadcasts.

Key features of the DX-394 include:

• PLL frequency control for precise tuning and stability.
• Large LCD display showing time, frequency band, set frequency, signal strength, and more.
• Five programmable timers for time display and on/off control.
• Cassette recorder output.
• Automatic search function.
• Memory for up to 160 frequencies for quick access to favorite stations.
• Direct frequency input via keypad.
• Large manual tuning knob.
• Keypad and control lock to prevent accidental changes.
• Variable RF gain.
• Front headphone jack.
• External speaker jack.
• Monitor memory for temporary frequency storage.
• Antenna outlets for low-impedance and longwire antennas.
• ATT switch for an attenuator circuit (works on low-impedance outlet).
• Memory backup powered by a lithium battery for approximately one month after power loss.
• Dual power supply options: 220V AC or 12V DC (battery or adapter).

The DX-394 covers the following frequency bands:

The SW band is further divided into 13 international meter bands:

Preparations

Placement

For optimal performance, an external antenna is usually required. Place the receiver in a location where an antenna cable can be run. Choose a comfortable spot as you will likely spend many hours using the receiver.

Grounding

For best performance, the unit should be grounded. A ground screw is located on the back of the unit. Connect a cable from the ground screw to a heating element or a metal part of a faucet or thermostat. If you live on a ground floor, you can also connect the ground cable to a metal rod driven into the ground.

Antenna

A telescopic antenna is included and screws into the top of the casing. Extend it fully during use. While sufficient for strong signals, an external antenna is recommended for full DX-394 performance.

A simple longwire antenna (a long copper wire suspended between two insulated points, ideally over 10 meters long and as high as possible) is a good compromise. Connect it to the ANT HI-Z outlet.

For specific frequencies or bands, a dipole antenna tuned to that range can provide better performance. The length of the dipole wire is determined by the frequency. A dipole works best on its tuned band but can be used on others with reduced effectiveness.

Power Connection

The DX-394 has a built-in power supply. Connect the power cord to a 220V wall outlet. Alternatively, it can be powered by a 12V DC source (requiring 2A).

Resetting the Unit

If the display freezes or the unit malfunctions, you may need to reset it. Note: Resetting will erase all stored memory. Insert a pointed object (like a straightened paperclip) into the hole labeled RESET and gently press the internal switch.

Headphone Connection

Connect headphones to the front jack labeled HEADPHONES. It uses a 3.5mm MONO plug. Adapters are available for stereo headphones.

External Speaker Connection

Connect an external speaker (8 ohm impedance, 5-watt capacity) to the 3.5mm jack on the back labeled EXT SPKR.

Cassette Recorder Connection

Connect a cassette recorder to the TAPE OUT jack on the back. Run the cable to the microphone input of the recorder.

Controls and Display

Knobs and Buttons

• VOLUME: Volume control.
• RF GAIN: Adjusts receiver sensitivity.
• MODE: Selects modulation type (AM, LSB, USB, CW1, CW2).
• FINE TUNE: For fine-tuning, especially for CW and SSB.
• Large Frequency Knob: Manual frequency tuning.
• STEP / STEP PN: Selects frequency step size (0.1, 1, 5, or 10 KHz).
• TIME SET: Used for setting the clock.
• SLEEP: Activates sleep timer (30 or 60 minutes).
• DIMMER: Adjusts display backlight brightness.
• POWER: On/Off switch.
• TIMER: Used for setting the five programmable timers.
• NB (Noise Blanker): Enables/disables a circuit to suppress interference.
• MON: Stores the current frequency in Monitor memory.
• LOCK: Locks the frequency knob and most buttons (except POWER and LOCK).
• LIMIT: Used for setting frequency range for scanning.
• BAND: Selects LW, MW, or SW bands.
• METER: Selects one of the 13 international shortwave bands.
• ▲ / ▼: Used for frequency scanning and setting frequency ranges.
• CLEAR: Used for erasing input or errors.
• PGM: Used for programming various functions.
• Decimal Point: Input decimal values.
• ENT: Stores a frequency in memory.

Display Indicators

• 10 10: Indicates SLEEP TIMER is set for 30 or 60 minutes.
• (3) [Clock Icon]: Displays time for two time zones.
• TIMER ON/OFF: Indicates which of the 5 timers is active.
• SIGNAL STRENGTH: Bar graph indicating signal strength.
• LIMIT: Appears when the LIMIT function is active.
• LW, MW, SW: Indicates the currently active band.
• m [Meter Band Icon]: Appears when a shortwave meter band is selected or when using the LIMIT function with ▲ or ▼.
• PGM CH [Number]: Shows the programmed channel number.
• NB: Appears when the noise blanker is active.
• MON: Appears when the receiver is tuned to a frequency in Monitor memory.
• STEP (KHz): Shows the current frequency step setting.
• [Lock Icon]: Appears when the LOCK function is active.

Operation

Basic Operation

1. Turn VOLUME fully counter-clockwise and RF GAIN fully clockwise before powering on.
2. Select the desired modulation type (AM, LSB, USB, CW1, or CW2).
3. Press POWER to turn the unit on. If the clock flashes, it needs to be set.
4. Press BAND until the desired band (LW, MW, or SW) is displayed.
5. Tune to the desired frequency.
6. Adjust VOLUME to a comfortable listening level.

Press POWER to turn off the receiver when finished.

Setting Modulation Type

Different stations use different modulation methods. AM is used for general broadcasting. SSB (LSB/USB) is common for amateur radio. LSB is typically used below 14 MHz, and USB above 14 MHz. CW1 or CW2 are for telegraphy. STANDBY is a power-saving mode where only the POWER button is active.

Selecting Bands

Press BAND until the desired band (LW, MW, SW) appears on the display.

Selecting Meter Bands

Press METER. The selected band will flash on the display for 10 seconds. While flashing, press the corresponding meter band number (e.g., 90m) to tune to that band.

Setting Scan Range

You can define a frequency range for automatic scanning:

1. Press LIMIT.
2. Press PGM. ▲ will flash on the display.
3. Enter the lower frequency limit (e.g., 150 for 150 KHz, 1000 or 1 for 1 MHz, 10000 or 10 for 10 MHz). Press CLEAR if you enter an invalid frequency and try again.
4. Press LIMIT again.
5. Enter the upper frequency limit.
6. Press ENT to store the range.
7. Press ▲ or ▼ to start scanning.

Press LIMIT again until the text disappears to exit scan range mode. Stored frequencies remain until a new range is programmed.

Tuning to a Station

You can tune using the frequency knob, ▲/▼ buttons, direct keypad entry, or by recalling stored memory frequencies.

Keypad Frequency Entry

1. Press FREQ. The display will flash.
2. Enter the desired frequency using the keypad (e.g., 478 for 478 KHz). Use CLEAR to correct errors. Invalid frequencies will show ERROR; press CLEAR and wait 5 seconds before re-entering. The receiver rounds to the nearest valid frequency based on the step setting.
3. Press ENT to confirm.

Scanning

Press and hold ▲ or ▼ for about 2 seconds to start scanning up or down the frequency spectrum. The receiver stops at the next strong signal. For weaker signals, use manual tuning. If RF GAIN is fully clockwise, scanning will not initiate; turn RF GAIN counter-clockwise first.

Storing Frequencies in Memory

You can store up to 160 favorite frequencies (channels): 10 for LW, 10 for MW, 10 for SW, and 10 for each of the 13 meter bands.

1. Tune to the desired frequency using keypad or manual tuning.
2. Press PGM. PGM and CH will flash.
3. Enter the channel number (1-10; use 0 for channel 10).
4. Press ENT while PGM and CH are flashing to store the frequency.

Repeat for other channels or bands.

Using Monitor Memory

The Monitor memory stores one frequency temporarily.

1. Tune to the desired frequency and press MON. The previously stored frequency will appear.
2. Press ENT to store the new frequency in Monitor memory.
3. Press MON anytime to recall the stored frequency.

Using the RF GAIN Control

RF GAIN adjusts the receiver's input amplification. Unlike VOLUME (output amplification), RF GAIN helps manage strong signals that might otherwise overpower weaker adjacent ones. Reduce RF GAIN when listening to weak stations near strong ones.

Using FINE TUNE

FINE TUNE is for precise adjustments, especially for telegraphy (CW) and SSB (LSB/USB) signals.

Setting Frequency Step

Press STEP ▲ or STEP ▼ to change the frequency tuning increment (e.g., 100 Hz to 10 KHz). The display shows the current step.

Setting MW Step (9 KHz / 10 KHz)

To switch between 9 KHz (common outside North America) and 10 KHz (North America) steps for MW band reception:

1. Turn the receiver OFF.
2. Press and hold STEP ▲ or STEP ▼.
3. While holding the STEP button, press POWER ON.

Repeat the process to revert to the previous setting.

Using the DIMMER Button

Adjusts the brightness of the display backlight.

Using the LOCK Button

Pressing LOCK disables the frequency knob and most buttons, preventing accidental changes. Only POWER and LOCK remain active.

Using the ATT Switch

The ATT switch on the rear panel has 0dB (normal sensitivity) and 20dB (attenuated) settings. The 20dB attenuation reduces receiver sensitivity and is useful for listening to weak stations near strong ones. This switch only affects the ANT LO-Z outlet.

Setting the Clocks

The receiver has two clocks. It is recommended to set one to local time and the other to UTC/GMT, as many shortwave stations broadcast times in UTC/GMT.

1. Press and hold TIME SET for 2 seconds. The display will show ■ and the time digits will flash.
2. Enter the current time using the keypad (e.g., 930 for 9:30). Use CLEAR for errors.
3. Press TIME SET again to select clock 2. Only the hour digits will flash.
4. Enter the hour for clock 2. Clock 2 uses the same minutes as clock 1.
5. Press ENT to start both clocks.
6. Press TIME SET to alternate between viewing clock 1 and clock 2.

Timer Settings

The receiver has five programmable timers. Each timer can store a frequency, an activation time, and a deactivation time. When activated, the receiver will turn on at the programmed time and frequency. It will turn off at the programmed deactivation time. All timers are linked to Clock 1 (local time).

Programming a Timer

1. Tune to the desired frequency.
2. Press TIMER.
3. Enter the timer number you wish to program (you have about 10 seconds).
4. Press PGM to select the timer.
5. Press TIMER.
6. Enter the desired start time.
7. Press TIMER.
8. Enter the desired stop time.
9. Press ENT to save the settings.

Activating a Timer

1. Press TIMER.
2. Enter the number of the timer you want to activate.
3. Press ENT.

Repeat steps 1-3 to activate multiple timers. Press POWER to turn off the receiver.

Resetting a Timer

When the receiver is off:

1. Press POWER to turn the receiver on.
2. Press TIMER.
3. Enter the number of the timer to reset.
4. Press CLEAR.

When the receiver has started via a timer:

1. Press POWER. The timer will be reset, and the receiver will turn off.

Using the SLEEP Timer

The SLEEP Timer allows the receiver to turn off automatically after 30 or 60 minutes.

1. Press SLEEP until the desired time (30 or 60 minutes) is indicated on the display.
2. To turn off the receiver before the SLEEP Timer expires, simply press POWER.
3. To disable the SLEEP Timer, press SLEEP until the indicator on the display turns off.