Malahit DSP1 User Manual

1 Product Profile

1.1 Product Function Introduction

• Frequency range: 50kHz-250MHz, 400MHz-2GHz
• Panoramic width: 160kHz, 80kHz, 40kHz
• Modulation type: AM, SSB, DSB, CW, NFM, WFM
• Sensitivity: 0.3uV up to 1GHz
• Dynamic bandwidth: 82dB
• Antenna: 50 Ohm female female pin SMA connector
• High impedance mode (DSP1 with optional board)
• Built-in preamplifier
• Power: 5000mAh lithium-ion battery
• Software features: adjustable filter width, Adaptive Noise Reduction (NR), threshold noise reduction, Noise Blanker (NB), Automatic Gain Control (AGC), Automatic trap (ANF), Stereo FM Support RDS Analog Stereo equalizer
• Hardware features: STM32H743 ARM CPU Frequency 480MHz, MSI001 Multiband, Multimode Tuner, 3.5" 480x320 LCD high brightness capacitive touch screen, Front cavity dual-diaphragm speakers
• IP6X Mechanical Encoders
• Pure aluminum alloy shell design

1.2 Product Specifications

• Product external size: 142mm*95mm*30mm
• Product weight (single machine): 500g (aluminum alloy shell)
• Packing list: Main unit x 1, SMA head trolley antenna x 1, carrying strap x 1, stand x 1, Type-C cable x 1, user manual x 1, EVA bag x 1

2 Getting Started

Assemble the receiver, screw on and unfold the supplied tie rod antenna, then toggle the power switch on the left side of the case, and you'll briefly see the power-up screen, then the main user interface screen.

The user interface includes:

• Indicator lights
• Signal strength meter (S-meter)
• Current tuning frequency and tuning step
• Headphone and speaker indicators
• Signal spectrum display (shows signal strength by frequency)
• Signal waterfall display (shows signal changes over time)
• Menu buttons

2.2 Introduction to common operations

• Entering the specified frequency: Touch the position of the frequency on the display and enter the specified frequency.
• To fine-tune the frequency: Rotate the receiver's Frequency knob.
• To change the step value of the trim frequency: Short press the Frequency knob, rotate it to change the step value, then short press the knob again to exit the step value setting.
• To change the volume: Turn the Volume knob of the receiver.
• Quickly set ATT, VOL, PLT parameters: Press the Volume knob briefly to switch between Volume VOL, Filter Width PLT and Attenuator ATT, then rotate the Volume knob to select the value.
• Change Panorama Width: Touch the waterfall display area to change the spectrum display bandwidth (160kHz, 80kHz, 40kHz).
• To change the modulation type: Touch the MODE button and select a new modulation type (e.g., AM, WFM, NFM, LSB, USB).
• Quickly close the screen: Tap the power button and tap it again to open the screen.
• To turn off the receiver: Press and hold the power button for a few seconds until the receiver emits Morse code beeps.
• Frequency knob, Volume knob other functions: To disable the touchscreen, press and hold the Volume knob for a few seconds until the receiver beeps. This reduces shortwave interference. To re-enable the touchscreen, press and hold the Volume knob again for a few seconds.
• To lock the currently adjusted frequency: Press and hold the Frequency knob for a few seconds until the receiver beeps. Press the Frequency knob again for a few seconds to unlock the frequency.
• Set the displayed clock: Press and hold the HARD button until the receiver beeps to display the Time Setting screen. Turn the Volume knob to change the value. Short press the Volume knob to advance to the next element. Press and hold the Volume knob to confirm the change.

3 Indicators and menus

3.1 Introduction to Screen Indicators

Indicators at the top of the screen show the status of various functions. If an indicator is gray, it is disabled.

• SQL: Green light indicates squelch triggered; red light indicates squelch enabled but not triggered.
• NB: Indicates noise canceler is enabled.
• NR: Indicates noise reduction is on.
• AGC-S: Displays the current automatic gain control status.
• ANT: Green light indicates Hi-Z antenna is enabled.
• PRE: Indicates the preamplifier is on.
• NFM: Displays the current modulation type (AM, WFM, NFM, LSB, USB).
• ATT: Displays the current attenuator setting in decibels (dB).
• VOL: Displays the current volume level.
• FLT NORMAL: Shows the width of the audio filter.
• 3.92: Displays the current battery voltage and status.

4 Menu Settings

4.1 Introduction to the Main Screen Menu

The home screen has menu buttons: HARD, AUDIO, VISUAL, NR, MODE, BAND.

• HARD: Sets radio signal processing functions.
• AUDIO: Sets audio processing functions.
• VISUAL: Sets spectrum and waterfall display, and other visual features.
• NR: Toggles noise reduction on and off.
• MODE: Switches between different modulation types.
• BAND: Saves and restores frequencies and settings.

4.2 Radio menu (HARD)

The HARD menu allows configuration of hardware features like RF gain, preamplifiers, and attenuators. Touch a menu item to select it. Rotate the FREQUENCY knob to toggle between values. Touch the HARD button again to exit.

• Encoder reverse (ENC reverse): Changes the rotation direction of encoders.
• IQ swap: Functionality not detailed.
• Shutdown control (Vbat control):
  • Standard: Shuts down when battery voltage falls below 3.3V.
  • Low: Operates until the battery is completely drained.
• Short wave antenna (SW antenna): Enables High Impedance (Hi-Z) input mode for better shortwave reception with tie rod or long wire antennas. ANT indicator turns green when active. Hi-Z mode is automatically disabled at high frequencies.
• Pre-Reamp Low Noise Amplifier (PREAMP): Switches the built-in preamplifier for input signals. Useful for weak signals, but amplifies noise. PRE indicator turns green when active.
• Attenuator (ATT): Attenuates HF input signals. Value displayed in decibels. Adjustable with Volume or Frequency knob. Use for powerful radio overload.
• Audio out: Controls audio output to speakers, headphone port, or both.
• RF Gain (RF GAIN): Adjusts signal gain at the MSI001 quadrature mixer. Increase for more input signal, decrease for less noise/distortion.
• Preamp gain attenuation (LNA/MIX UP GR): Attenuates strong signals. Behavior depends on frequency. Above 30 MHz, uses an internal amplifier reducing gain. Below 30 MHz, uses two mixers reducing first mixer input gain.
• Mixer Gain Attenuation (MIX GR): Attenuates strong signals. Behavior depends on frequency. Above 30 MHz, uses a built-in amplifier reducing mixer input gain. Below 30 MHz, uses two mixers reducing second mixer input gain.
• PGA Gain (PGA Gain): Adjust gain value using the screen and Frequency knob.
• Frequency offset correction (F correct): Corrects displayed frequency. Tune to a known frequency and adjust F correct until the displayed frequency matches.
• Level meter calibration (Sm correct): Corrects signal strength meter. Tune to a known signal strength and adjust Sm correct until the displayed strength matches.
• Cue Volume (BEEP LVL): Controls system beep volume.
• PGA BST: Enable for very strong signals that overload the receiver.
• Level meter display type (Ind type): Toggles between signal strength meter and decibels (dBm).
• Timed shutdown (Activity timer): Automatically shuts down if the receiver is not touched for a set period.
• Pre-Low Noise Amplifier Gain (PRE Gain Value): Value (in dB) subtracted from signal strength meter when pre-amplification is enabled, to correct S-meter reading.
• EMI Suppressor (EMI Reduction): Reduces display update frequency to minimize interference. Makes touchscreen less responsive.

4.3 Audio Menu (AUDIO)

The AUDIO menu configures sound characteristics like filtering, gain, noise reduction, noise cancellation, and squelch. Touch a menu item to select it. Rotate the Frequency knob to toggle values. Touch the AUDIO button again to exit.

• Noise Blanking (NB): Cancels incoming audio noise. Enable/disable with NB button. Threshold value sets trigger level (not recommended below 3). Config option toggles noise cancellation configurations.
• Automatic Gain Control (AGC): Adjusts audio amplification gain. Select among three AGC modes via AGC MODE. AGC GAIN controls amplification amount. AGC LIM sets cutoff limit.
• Filter: Provides three audio filter widths: normal, wide, narrow. Adjustable with Volume or Frequency knob. LOW freq and High freq set hard thresholds.
• Static Noise (SQL): Cuts off sound if level falls below SQL threshold value. Red SQL light: enabled but off. Green SQL light: on.
• Noise Reduction (NR): NR threshold specifies the threshold for noise reduction.
• Automatic Trap Filter (ANF): Suppresses carrier tone in LSB or USB modulation. Disabled for other types. Toggle with ANF button.
• Broadcast FM settings: EQ TYPE selects equalizer for FM broadcasts. WFM stereo switches FM stereo sound. Enable WFM stereo for RDS text messages or automatic scanning.
• Stereo effect simulation: PseudoStereo button enables stereo emulation from mono sound. Useful for music via headphones. Disabled for WFM modulation radio stations.

4.4 Visual Menu (VISUAL)

The VISUAL menu configures panorama and waterfall displays, sensitivity, color scheme, and other settings. Touch a menu item to select it. Rotate the Frequency knob to change values. Touch the VISAUAL button again to exit.

• Screen setup:
  • BRIGHT MAX: Controls regular screen brightness.
  • REDUCT TIME: Screen not operated for set time (seconds), reduces brightness to BRIGHT MIN value.
  • BRIGHT MIN: Screen not operated for set time, brightness reduced to this value.
  • LCD SLEEP: If enabled, screen turns off after a set number of seconds. Receiver continues to operate, screen comes on with touch.
• Waterfall Settings:
  • WF GAMMA: Choose between different color schemes for the waterfall diagram.
  • WF Gain: Makes waterfall plot more sensitive to weaker signals, but increases noise.
  • WF delay: Controls the speed of the waterfall graph.
• Spectrum Settings:
  • FFT color: Allows selection of the spectrum color.
  • FFT ave: Adjusts the average number of samples. Larger value = slower spectrum changes.
  • FFT scale: Determines spectrum amplitude range. Larger value = shorter spectrum display, larger signal amplitude.
  • FFT fill: Spectrogram fill display switch.
  • FFT level: Adjusts the horizontal position of the spectrum display.
  • FFT GRID: Turns spectrum area gridline display on or off.
  • Pan percent: Controls the ratio of spectrum plot to waterfall plot.
• Disable waterfall charts and spectra: Change ViewPan&WF options to disable waterfall graph and spectrum displays. Screen updates only when changing frequency or settings.
• DC voltage suppression: Suppresses DC signal component at 0 Hz offset. DC reject value controls rejection strength. Too high may create a gap.
• FM Frequency Scale: Provides a "vintage scale" view of the FM radio band. Retro Scale feature allows selection between European and Japanese FM band layouts.

4.5 Mode menu (MODE)

The MODE menu changes the current modulation mode and enables the CW decoder function. Touch a menu item to select it. Rotate the Frequency knob to change values. Touch the MODE button again to exit.

• Wideband frequency modulation (WFM): Used by commercial radio stations. WFM BW option selects normal or narrow modulation widths. Use narrow for interference from neighboring broadcasters.
• Narrowband frequency modulation (NFM): Used by police, first responder radios, and amateur radio operators on VHF/UHF bands.
• Amplitude Modulation (AM): Used by commercial stations on LW, MW, SW bands, and by sailors, pilots, and air traffic control. Option selects AM demodulator type (MAG, SAM, SAM U, SAM L). MAG is default. Change if AM signal is weak or interfered with.
• Lower Sideband Amplitude Modulation (LSB): Commonly used by amateur radio operators on 160M, 80M, and 40M bands.
• Upper Sideband Amplitude Modulation (USB): Commonly used by amateur radio operators on 20M and higher bands.
• Dual Sideband Amplitude Modulation (DSB): When used with LSB or USB, automatically selects sidebands with higher signal levels.
• Morse code (CW): Narrows audio filter to 1kHz for monitoring/decoding Morse code. LSB/USB indicators change to CWL/CWU. Not compatible with Noise Reduction (NR).
• CW Decoder: Attempts to decode Morse code transmissions. Adjust Min SNR to approx. 29 for optimal performance. To improve decoding, enable CW option and disable Noise Reduction (NR).

4.6 Channel Storage Menu (BAND)

The BAND menu saves and reads radio settings. Click BAND icon to open/exit. Tabs are page-by-page, turned by Frequency knob. Press and hold memory point to save frequency and parameters.

BAND PAGE 1 OF 5

5 FM Retro Scale (FM Retro Scale)

5.1 Introduction to Vintage Scale Watches

When using WFM modulation, the receiver provides a "vintage scale" view, similar to older wave-testing receivers.

Steps to access the vintage scale view:

1. Tune to the FM broadcast band (75-109MHz). Region (Europe/Japan) set in VISUAL menu's Retro scale option.
2. Select WFM modulation in the MODE menu.
3. Click twice in the waterfall chart position to switch to the FM frequency scale table. First click enters MPX interface, second click on bottom half of center screen.

Upon entering the vintage scale view:

• Use the Frequency knob to switch between stations.
• Click the lower half of the scale to return to the regular panorama view.
• Click the upper part of the scale to access the Vintage Scale menu.

The Retro Scale menu provides options for adding, deleting, and editing stations.

• Add/Edit Station (ADD/EDIT STATION): Use Frequency knob to adjust frequency, click ADD/EDIT STATION. Enter setup interface, call out station, press "ADD AND CONTINUE" to edit next station, or "ADD AND EXIT" to return to menu. Other operations: "DELETE STATION" to delete entry, "EXIT" to discard changes.
• Rename Scale (RENAME SCALE): Rotate Frequency knob to select a letter. Press Frequency knob to confirm and advance. Click "CLEAR NAME" to reset. Press SAVE AND EXIT to confirm, or CANCEL AND EXIT to discard changes.
• Clear Scale (CLEAR SCALE): Clears user-defined scale, stations, and names. Press CLEAR to confirm, or CANCEL to cancel.
• Switch User Scale (SWITCH USER SCALE): Toggles between two defined user scales.
• LOAD PRESET: Loads preset scales for cities. Current scale replaced with preset.
• AUTO SEARCHING: Scans FM band for stations and fills current scale.
• EXIT: Exits menu to return to Retro Scale view.
• CHANGE COLOR: Select vintage scale color by rotating Frequency knob or clicking color example. Press SAVE COLOR & EXIT to confirm, or CANCEL AND EXIT to discard changes.

5.2 Automatic search

The Retro scale scans for radio waves and fills the scale with found FM stations. Search range depends on region (Europe/Japan) set in VISUAL menu's Retro scale option.

To use automatic search:

1. Go to HARD menu, ensure headphone output is enabled in audio output options. Auto search unavailable if disabled.
2. Go to AUDIO menu, ensure WFM stereo option is enabled. Auto search unavailable if disabled.
3. Click upper part of scale to enter vintage scale menu, click "AUTO SEARCHING" button.

Auto Search screen shows progress bar, number of stations found, and frequency guide. Cancel with "CANCEL" button.

Upon completion, save results with "SAVE SCALE & EXIT" or discard with "CANCEL AND EXIT". Choosing to replace current scale with auto search result will lose previous scale content.

6 Connecting the Receiver to a Computer

6.1 Connecting the receiver to a computer

Assumes connection to Windows 10 or similar OS. Windows 10 has necessary drivers.

Requires a micro USB cable (like those for cell phones) that supports data connections.

After connecting and turning on the receiver, three new USB devices appear in Windows Device Manager:

• Malahit RX: Audio input device for sound from Malachite radio to computer. Can be used as a microphone.
• Malahit IQ: "Audio input" device that inputs entire 192kHz spectrum data. Usable with SDR software (HDSDR, SDR++, SDR#) to receive and process spectral data.
• Malahit CAT: USB serial port mode for changing frequency, modulation, volume, and other parameters via computer. Command set compatible with Kenwood TS-480.

When "Malahit USB" appears in Device Manager, ensure "Malahit RX" and "Malahit IQ" audio inputs are enabled in Windows Sound Control Panel.

Verify connection to HDSDR

Verify radio functionality with HDSDR software:

1. Install and run HDSDR.
2. Select "Options | Select Input | Sound Card".
3. Click "Sound Card", select "Malahit IQ" in "RX Input (from Radio)".
4. Click "OK".

After these steps, HDSDR should display the same spectrogram and waterfall display as the radio. Adjust frequency using radio's knobs.

6.2 Controlling the receiver from a computer

To adjust receiver frequency from a computer, interface OmniRig software with a "Malahit CAT" USB device.

1. Go to Windows Device Manager, locate COM port device for "Malahit CAT" (disconnect/reconnect receiver to identify).
2. Install and run OmniRig. Set "RIG 1" configuration:
   • Rig Type = TS-480
   • Port = <your COM port>
   • Baud Rate = 19200
   • Data Bits = 8
   • Parity = None
   • Stop Bits = 1
   • RTS = High
   • DTR = High
   • Poll = 500
   • Timeout = 4000
   Click "OK" to confirm.
3. In HDSDR, select "Options | CAT to Radio | Sync RIG1". Enable "Use v1", "Sync to Rig", "Sync from Rig", "Sync LO Frequency", and "Sync Modulation".

You can now control the Malahit receiver through frequency and other settings in HDSDR software.

7 Dealing with internal disturbances

7.1 Dealing with various internal disturbances

A Malahit receiver contains digital components (CPU, display, touch screen) that generate electromagnetic noise affecting reception quality. Common sources of interference and solutions:

• Noise when touching the screen: Manifests as buzzing sound, louder when touching screen. Move antenna away from receiver. Temporarily disable touchscreen by pressing and holding Volume knob for a few seconds. Knob still functions. Press and hold Volume knob again to re-enable.
• Display noise: Occurs in VHF bands as visible "bumps" or "spikes" on panoramic display. Move antenna away. Reduce display noise via RADIO menu by enabling EMI Reduction (slows updates, reduces interference, makes touchscreen less responsive). Temporarily disable display by clicking Power button. Knobs still function. Tap Power button again to re-enable display.

8 Selecting the right antenna

8.1 Antenna Introduction and Selection

Antenna selection depends on frequencies to receive and radio interference levels.

• rod antenna: Comes with the receiver. Usable on various frequencies if no strong electromagnetic interference sources nearby (e.g., power supplies, chargers, LED lights, refrigerators, air conditioners, water pumps).
• In Long Wave (LW), Medium Wave (MW), and Short Wave (SW) bands (<30MHz), the original tie rod antenna is not ideal but usable. To improve reception, go to RADIO menu, enable SW antenna option for high impedance (Hi-Z) mode. ANT indicator turns green. Hi-Z mode disabled at higher frequencies. Enable PREAMP option for increased signal amplification (may increase noise).
• Other tie rod antennas work similarly. Longer antennas are more sensitive at lower frequencies. More expensive ones use stronger materials and offer better tuning. Examples: Comet SMA-W100RX, Diamond SRH789. Some have BNC connectors requiring a BNC to SMA adapter. Heavier antennas stress the SMA connector.
• Long wire antennas (LW, MW, SW): Optimal length is ~1/2 wavelength. Example: for 25-meter shortwave band, optimal length is ~12.5 meters. Connecting a long wire to the antenna connector is possible. Shortwave radio manufacturers offer antennas with retractable wires (e.g., Sangean ANT-60, Tecsun AN-05, XHDATA AN-80). Long wire antennas are susceptible to electromagnetic interference.
• Rubber whip antenna (VHF, UHF): For shorter wavelengths (above 80 MHz). Used for walkie-talkies, emergency radios, scanners. Small, portable, good reception in FM, VHF, UHF bands. Examples: Nagoya NA-701, NA-771; Comet SMA-501, SMA-503. Tuned for VHF/UHF bands, not useful in LW, MW, SW bands.
• loop antenna: Addresses electromagnetic interference indoors or in urban environments by receiving the magnetic component of the signal instead of the electrical component. A typical loop antenna has small coils connected via a transformer. Larger coils are more sensitive. Loop antennas are directional. Loop antennas are more resistant to EMI but less sensitive than conventional antennas. Many commercial loop antennas have low-noise amplifiers. Examples: YouLoop, MLA-30+, GA-450.