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Malahit DSP2 version 2.40

Malahit DSP2 is a portable SDR (Software-Defined Radio) receiver, originally developed in Russia, known for its versatility and high performance compared to other portable radios. It is designed to receive signals over a wide range of frequencies with advanced demodulation capabilities, thanks to its built-in DSP (Digital Signal Processing) chip. 

Here’s an overview of its key features and functionalities:

Key Features

• Frequency Range: The Malahit DSP2 can receive signals across a wide frequency range, typically between 50 kHz and 2 GHz (or more, depending on the version). This covers HF (High Frequency), VHF (Very High Frequency), and UHF (Ultra High Frequency) bands.

• Touchscreen Display: It comes with a color touchscreen display, offering easy and intuitive control of functions, including frequency navigation and access to configuration options.

• SDR Reception: As an SDR receiver, all modulation and filtering are handled via software, providing great flexibility for future updates and functionality improvements.

• Advanced DSP Support: With its integrated DSP chip, the Malahit DSP2 delivers high-quality demodulation for various signal types, including AM, FM, SSB (Single Side Band), a decoder CW (Continuous Wave), RTTY and FT8.

• Customizable Filters: The receiver offers adjustable band-pass filters to reduce noise and enhance signal selectivity, allowing users to tailor the bandwidth according to operational needs.

• Built-in Rechargeable Battery: Powered by an internal lithium-ion battery, the Malahit DSP2 is extremely portable and ideal for mobile use. Battery life depends on usage, but you can count on about ten hours of listening time.

• Firmware Updates: It supports firmware updates, allowing users to enhance the device over time with new features or bug fixes.

• Multiple Antenna Options: Malahit DSP2 can support two types of antennas, thanks to standard signal input connectors: 50 Ohm and Hi-Z both with SMA connectors.

Functionalities

• Multiple Demodulation Modes: It supports a wide range of demodulation modes, including AM, SSB, NFM (Narrowband Frequency Modulation), WFM (Wideband Frequency Modulation), and CW:  suitable for listening to different types of transmissions, such as broadcast radio, amateur radio, military signals, and aeronautical communications.

• Recording Function: The Malahit DSP2, depending on the model and software, allows users to record received signals onto an external memory card, useful for post-analysis or archiving important transmissions.

• Spectrum and Waterfall Display: The receiver provides a spectrum display and waterfall view to monitor signals across frequency bands. This is particularly useful for quickly identifying weak signals or interference.

• Fast Tuning: Tuning can be done precisely via the physical tuning knob or directly using the touchscreen, making it easy to use for quick band searches.

• Noise Reduction: It implements various noise reduction (NR) techniques and automatic gain control (AGC) to improve listening quality under difficult conditions.

• Portability: Its compact design and built-in battery make it ideal for field use or situations where portability is essential. Weight: 504 grams. 

• 100x 135x 23mm

How it looks like

Typically, the first action one takes when buying a new receiver is to turn it on and tune in immediately to some known radio station or sampling frequency to make sure the receiver is receiving the exact frequency, and in a few lines I will explain how to be active right away, but even before that, curbing impatience, one must set the clock.

In the frequency spectrum screen I recommend tuning to 9.995.0 in USB mode. It is a sample frequency. 

Set accurate date and time

Long press the lower left RADIO button and you are presented with this menu where, with the volume knob, you can change the data there. Turning the knob will scroll back and forth through the calendar, and pressing on the same knob will change the field (from days to month, year, time, etc.). Click on SET TIME to confirm.

However, I have noticed that the clock is not accurate, it goes on. And this is a problem in the FT8 mode where absolute clock accuracy is required.

You can work around the problem by pressing the CALFT8 button which synchronizes the reception with the receiver.

To correct this problem for the other transmission modes or, more simply, to have the exact clock, press the RADIO button and in the menu select Time correct, 

calculate how many seconds the receiver is going forward or backward, turn the frequency knob (left) forward or backward depending on your receiver’s delay or advance.

Now, we see all the default screens

This can be useful to check the settings before doing RESET because in the beginning, when you are not yet familiar with the receiver, it happens to enter wrong parameters, and there are hundreds of parameters in this receiver.

RESET 

In the RADIO screen press down the two VOLUME and FREQUENCY knobs at the same time.and wait a couple of seconds. 

A “beep” will be heard and the receiver,after the home screen where we will see the Malahit home page with programmer emails, will take us to the listening screen with the frequency spectrum and waterfall just below.

Spectrum analyzer

LISTENING

Before delving into the explanation of the controls and parameters of this receiver, I prefer to explain in which way it can be received well without too many adjustments.

For me, the PREAMP and LNA/MIX UP GR commands worked well. To activate them just click on them, the wording changes from Disable to Enable and the borders turn green. This immediately increases the signal which becomes more listenable without increasing the volume.

NR Function

Most importantly, activate the NR (Noise Reduction) function, which digitally eliminates most background noise.

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Malahit DSP2 hums and freezes every 20 seconds

Only in FT8 mode and about every 20 seconds Malahit DSP2 stops for a second or so and emits a loud buzzing sound. And there is a reason for that.

It is not a fault of the receiver but the way of carrying a block of callsigns with related data from the receiver memory to the screen. Then you will notice that after the buzzing and blocking, a number of logs appear on the screen.

Set accurate date and time

Long press the lower left RADIO button and you are presented with this menu where, with the volume knob, you can change the data there. Turning the knob will scroll back and forth through the calendar, and pressing on the same knob will change the field (from days to month, year, time, etc.). Click on SET TIME to confirm.

However, I have noticed that the clock is not accurate, it goes on. And this is a problem in the FT8 mode where absolute clock accuracy is required.

Warning. If you forget to disable the FT8 button, the buzzing will continue on all radio listening frequencies.

FT8 is always transmitted in USB mode, regardless of the operating frequency. 

CALFT8 soft key

Press and hold the CAL FT8 function button at the start of the FT8 transmission cycle. This will synchronize the clock to the nearest minute, allowing the decoder to function correctly.

Note that the radio’s clock might be set accurately, but it could also be off by 15, 30, or 45 seconds. This is because FT8 cycles begin every 15 seconds, and it’s not immediately clear which period aligns with the radio’s clock at zero seconds.

FT8 (Franke-Taylor 8) is a digital transmission mode primarily used in amateur radio communications, designed to facilitate long-distance communication with very weak signals. It was developed by Joe Taylor (K1JT) and Steve Franke (K9AN) as part of the WSJT-X software suite, which is widely used by amateur radio operators.

Key features of FT8 include:

• Low-power efficiency: FT8 is optimized to work with extremely weak signals, often below the noise level, making it ideal for challenging conditions and long-distance (DX) contacts.
• Fast transmission cycles: Each transmission and reception cycle lasts about 15 seconds, making it faster than other digital modes like JT65.
• Narrow bandwidth: FT8 occupies a very narrow bandwidth of around 50 Hz, allowing efficient use of radio spectrum.
• Time synchronization: FT8 requires precise system clock synchronization, as transmissions and receptions must be closely aligned in time.

FT8 is especially popular among amateur radio operators who aim to make long-distance contacts under poor propagation conditions or with less efficient antennas.