Malahit-DSP and Malahit-DSP2 Receivers

User Manual and FAQ
last updated June 26 2022

This document describes Malahit-DSP and Malahit-DSP2 wide-band radio receivers, designed by Georgy Yatsuk (RX9CIM), Vladimir Gordienko (R6DAN), Vladimir Burlakov (R6DCY), and Igor Naumenko. These receivers are developed, built, and sold from Yekaterinburg, Russia. Both receivers are based on the SDR architecture, where most of the signal processing is done in the software. They have the following features:

While the Malahit-DSP1 receiver is no longer being made, you can order Malahit-DSP2 by emailing malahit_sdr@rambler.ru or from the online store:

https://malahiteam.com/en/

Contents

• Assembling the Receiver
• Getting Started
• Exploring the Indicators and Menus
• The Radio Menu
• The Audio Menu
  • Noise Blanking (NB)
  • Automatic Gain Control (AGC)
  • Filtering (FILTER)
  • Squelch (SQL)
  • Noise Reduction (NR)
  • Automatic Notch Filter (ANF)
  • Broadcast FM Settings
  • Stereo Effects Simulation
• The Visual Menu
  • Screen Settings
  • Waterfall Settings
  • Panorama Settings
  • Disabling Waterfall and Panorama
  • DC Rejection
  • FM Scale Selection
• The Mode Menu
• The Band Menu
  • Monitoring Memory Slots
  • Monitoring Groups of Memory Slots
• The FM Retro Scale
  • The Auto Search
• Connecting Receiver to a Computer
  • Verifying Connection with HDSDR
  • Controlling Receiver from a Computer
• Updating Firmware
• Dealing with Internal Interference
  • Touch Screen Noise
  • Display Noise
• Choosing the Right Antenna
  • Telescopic Antennas
  • Long Wire Antennas (LW, MW, SW)
  • Rubber Whip Antennas (VHF, UHF)
  • Loop Antennas
• Accessories
  • Connecting BNC Antennas
  • Magnetic USB Cables
  • Better Encoder Knobs
  • Custom Stands
  • Bluetooth Transmitters
  • Ferrite Antennas
  • SV2CZF Antennas
• Modifications and Repairs
  • Changing DIP Switches
  • Using Two 18650 Cells
  • Replacing SMA Connector
  • Fixing and Replacing Encoders
• Useful Resources
  • Other Documentation
  • General SDR Software
  • Digital Radio Software
  • General Reference

If you have an assembled receiver, please, skip over this section and go to the next one. Otherwise, read on.

The receiver is shipped as a kit, without a battery. Hence, you will need to obtain a single, good, flat-top, unprotected 18650 lithium-ion cell prior to assembling the receiver. Protected button-top cells will not fit into the receiver. Manuel Maliszewski has published a review of available 18650 cells , where he suggests using Panasonic / Sanyo NCR18650B or NCR18650GA cells. 18650 cells can be purchased from this online store:

https://www.18650batterystore.com/

Once you obtain an 18650 cell, take a Phillips screwdriver and follow these instructions to assemble the receiver:

1. Insert the 18650 cell into its holder, found at the rear half of the receiver. Make sure it is installed in the correct polarity, with the positive end facing the red wire.
2. Check all wires for cracks, make sure they are firmly connected to the circuit board.
3. Put two halves of the receiver together, sliding them into the tracks. Make sure no wires are clamped or otherwise damaged in the process.
4. Holding receiver halves together, attach left and right covers, securing them with a screwdriver. Make sure that the LED, headphone connector, power button, and USB connector match holes found in the right-side cover.

Once you have your receiver assembled, attach and extend the included telescopic antenna, then click the power button found at the right side of its case. You should briefly see the title screen, followed by the main user interface screen:

From top to the bottom, this screen contains the following components:

1. Various indicators, discussed further in this document.
2. Signal strength meter (S-meter).
3. Currently tuned frequency and tuning step.
4. Headphone and speaker indicators.
5. Panorama display showing signal strength by frequency. The vertical line at the middle is your currently tuned frequency.
6. Waterfall display showing how signal changed over time.
7. Menu buttons, discussed further in this document.

To change the frequency...
Touch the frequency display then use the touch screen to enter a new frequency.

To tune the frequency...
Rotate the larger knob found at the front of the receiver.

To change the tuning step...
Click on the larger knob, rotate it to change the step then click it again.

To change the volume...
Rotate the smaller knob found at the front of the receiver.

To change between volume, filter width, and attenuator...
Click the smaller knob, rotate it to select what you want to change, then click it again.

To change panorama width...
Touch the lower half of the panorama display. The current width is indicated at the top-left corner of the panorama.

To change modulation type...
Touch the MODE button, then use the touch screen to select a new modulation type, such as AM, WFM, NFM, LSB, or USB.

To quickly turn the screen off...
Click the power button. Clicking it again will turn the screen back on.

To turn the receiver off...
Press and hold the power button for a few seconds. The receiver will issue a series of Morse code beeps (guess what they mean) and then turn itself off.

Two more functions are toggled with the knobs found at the front of the receiver:

To disable touch screen...
Press and hold the smaller knob for a few seconds. Disabling touch screen will reduce the shortwave interference. You will still be able to tune the receiver by using knobs. Press the smaller knob again to reenable the touch screen.

To lock the currently tuned frequency...
Press and hold the larger knob for a few seconds. Press the larger knob again to unlock frequency tuning.

Finally, to set the clock shown at the top-right corner...

1. Hold the RADIO button until the receiver beeps, showing the time setup screen.
2. Rotate the smaller knob to change values.
3. Click the smaller knob to advance to the next element.
4. Once the date and time are entered, press and hold the smaller knob to confirm changes.

The top of the main screen contains a row of indicators, grayed if disabled, as follows:

The bottom of the main screen contains a row of menu buttons, as follows:

In the following sections, we will go over each of the above menus in greater detail.

The RADIO menu lets you configure various hardware features, such as radio frequency gain, pre-amplifier, attenuator, and so on. Touch a menu item to select it. If an item has more than two different values, rotate the larger knob to change between these values. To exit the menu, touch the RADIO button again. This menu contains the following items.

The AUDIO menu lets you configure various sound characteristics, such as filtering, gain, noise reduction, noise blanking, and squelch. Touch a menu item to select it. If an item has more than two different values, rotate the larger knob to change between these values. To exit the menu, touch the AUDIO button again. This menu contains the following sections.

The noise blanking feature is used for cancelling the incoming audio noise. You can enable or disable this feature by clicking the NB button. The Threshold value sets the triggering level. It is not recommended to set it below 3. The Config option switches between several different noise blanking configurations. Both parameters depend on the type of a noise you are trying to blank and thus need to be adjusted by ear.

The automatic gain control feature is used for automatically adjusting audio amplification gain. You can choose between three different AGC modes with the AGC MODE option. The AGC GAIN value controls how much amplification is applied. The AGC LIM value sets cut-off limit for automatic gain control.

The Filter option offers three different audio filter widths: normal, wide, and narrow. This is the same value as displayed at the top-right corner of the screen. It can also be changed with the smaller knob. The additional Low freq and High freq values set hard thresholds on what sound frequencies can pass through.

The squelch feature, when enabled with the SQL button, will completely cut off sound if its level is below a certain threshold, specified via the SQL threshold value. The red SQL light at the top of the screen indicates that the squelch is enabled, but "closed". Once the sound level exceeds the threshold, the squelch "opens" and the SQL light goes green.

The NR threshold value specifies the sound level at which the noise reduction is applied.

The automatic notch filter allows to suppress carrier tone when using LSB or USB modulation. This ANF is disabled for other modulation types. To toggle the filter, click the ANF button.

Two of the remaining items have to do with the FM broadcast reception. The EQ TYPE option selects the equalizer type applied to the FM radio. The WFM stereo option toggles FM stereo sound. Please note that you have to enable FM stereo if you would like to see textual RDS information transmitted by FM radio broadcasters or automatically scan FM band for stations.

Finally, the PseudoStereo button enables stereo simulation from mono sound. For obvious reasons, it is only useful when listening via headphones. The pseudo stereo mode is disabled when listening to FM broadcast stations using WFM modulation.

The VISUAL menu lets you configure panorama and waterfall displays, changing their sensitivity, color scheme, and other settings. Touch a menu item to select it. If an item has more than two different values, rotate the larger knob to change between these values. To exit the menu, touch the VISUAL button again. This menu contains the following items.

The regular screen brightness is controlled by the BRIGHT MAX value. If the screen is left alone for REDUCT TIME seconds, it will reduce brightness to the BRIGHT MIN value. If you enable the LCD SLEEP option, the screen will turn off after the receiver is left alone for selected number of seconds. The receiver will continue operating though, with the screen going back on once you touch it, or any of the knobs.

The WF GAMMA option allows to choose between several different color schemes for the waterfall. The WF Gain value can make waterfall more sensitive to weaker signals, at the cost of showing more noise. Finally, the WF delay value controls the waterfall speed.

The FFT color option allows to choose the panorama color. The FFT scale value determines panorama sensitivity. Finally, the FFT fill option toggles between plain and filled panorama styles.

The screen percentage taken by the panorama, relative to the waterfall, is controlled by the Pan percent value.

To reduce interference from the screen, you may want to disable both waterfall and panorama displays by changing the View Pan&WF option. With both waterfall and panorama disabled, the screen will only update when you change the frequency or other settings. This also applies to the S-meter.

For proper operation, the receiver supresses the direct current (DC) signal component that occurs at the 0Hz offset within panorama. While the DC component does not affect signal reception, it may show up as a spike at the dead center of the panorama. The DC reject value controls the supression strength. Setting it too high may create a "gap" at the panorama center though.

The receiver includes a separate "retro scale" view of the FM broadcast band, similar to the old shortwave receiver front panels. While the retro scale feature will be discussed later in this document, the FM band layout changes from country to country. The Retro scale option allows to choose between European and Japanese FM band layouts.

The MODE menu lets you change current modulation mode (displayed at the top of the screen), as well as enable the CW decoder feature. Touch a menu item to select it. If an item has more than two different values, rotate the larger knob to change between these values. To exit the menu, touch the MODE button again. This menu contains the following items:

The BAND menu allows to save and restore current receiver settings to a collection of memory slots. These slots are organized into pages, flipped by rotating the larger knob. To exit the menu, touch the BAND button again, or touch the EXIT button.

To save current settings to a memory slot...
Touch and hold chosen slot for a couple of seconds, until you hear a beep. You will then be offered opportunity to name saved slot.

To restore settings from a memory slot...
Briefly touch chosen slot.

The band monitoring mode is entered by touching the MONITOR SETTING button in the BAND menu. It lets you monitor selected memory slots for activity.

Once in the band monitoring mode, you can quickly browse through memory slots by rotating the larger knob. All monitored slots are marked in BLUE. A slot can be skipped from monitoring by touching the SKIP button. All skipped slots are marked in GRAY.

After you touch the START button, the receiver will automatically scan through monitored slots until the STOP button is pressed. The number of seconds the receiver stays at each slot is selected by touching the TIMEOUT button.

Each memory slot has associated optional squelch level. If the signal level is below that squelch level, the monitor will automatically skip to the next slot. The squelch option can be toggled by selecting a slot with the larger knob and touching the SQL button. Once the squelch is enabled, its level can be adjusted by touching the SQL LEVEL button.

To exit back into the BAND menu, touch the BACK button. To exit all menus at once, touch the SAVE & EXIT button.

The receiver offers four groups of memory slots that can be monitored separately from each other and the main monitor. These groups, called "submonitors", are accessed by touching the SUBMON 1-4 button at the main monitoring screen.

The submonitor screen has four START SMx buttons that start scanning corresponding submonitors. There are also four SET SMx buttons for editing each submonitor. Once you touch a SET SMx button, select memory slots with the larger knob, then touch the SET/RESET button to include or exclude them from a submonitor. The BACK button will always take you to a previous screen.

When using WFM modulation, the receiver offers the "retro scale" view, similar to the front panels found in the old shortwave receivers.

To enter the retro scale view...

1. Tune receiver to the FM broadcast band (75-109MHz). The active FM bands depend on the geographical region set with the Retro scale option in the VISUAL menu.
2. Select WFM modulation type in the MODE menu.
3. Click on the waterfall display twice, until the retro scale shows up.

Once in the retro scale view...

1. Use the larger knob to move between stations.
2. Click on the lower half of the scale to go back to the regular panorama view.
3. Click on the upper half of the scale to enter the retro scale menu.

The retro scale menu, invoked by clicking on the upper half of the scale, offers options to add, delete, and edit stations. It contains the following buttons:

The retro scale lets you scan the airwaves and populate your scale with found FM stations. The searched FM bands depend on the country set with the Retro scale option in the VISUAL menu. In order to use the auto-search feature, follow these steps:

1. Go into the RADIO menu and make sure that the headphone output is enabled in the Audio out option. The auto-search will not work with the headphone output disabled.
2. Go into the AUDIO menu and make sure the WFM stereo option is enabled. The auto-search will not work with the WFM stereo disabled.
3. Go into the retro scale menu by clicking on the upper half of the scale and click the AUTOSEARCHING button.

The auto-search screen shows the progress bar, the number of found stations, and the pilot tone indicator. The auto-search can be cancelled at any moment by clicking the CANCEL button.

Once the auto-search completes, it presents the choice of saving the results to your current scale with the SAVE SCALE & EXIT button or abandoning them with the CANCEL button. Keep in mind that the prior contents of the scale will be lost if you choose to replace them with the auto-search results.

The following instructions assume that you are connecting the receiver to a PC running Microsoft Windows 10 or similar operating system. Windows 10 is supposed to have all the drivers needed to interface it with the Malahit receiver and thus does not require any third party drivers.

You will need a micro USB cable (shipped with most cell phones) to connect Malahit to a PC. Make sure your micro USB cable supports data connections. Once you connect the receiver to any available USB port on your PC and turn the receiver on, you should see the following three new USB devices in the Windows Device Manager panel:

• Malahit RX
  This is the audio input device that brings sound from the receiver into the computer. You can use it the same way you would use a regular microphone device.
• Malahit IQ
  This device is also treated as an "audio input" of sorts, but it carries the entire 192kHz of the panorama data. You can use this device with various SDR software packages (such as HDSDR, SDR++, or SDR#) to receive and process the same panorama as received by the Malahit.
• Malahit CAT
  This is a USB-connected serial port used to tune Malahit's frequency, select modulation, volume, and other parameters. The command set used by the receiver is compatible with the Kenwood TS-480 command set.

Once you have verified that the Malahit USB devices show up in the Windows Device Manager panel, go into the Windows Sound Control panel and make sure both "Malahit RX" and "Malahit IQ" sound inputs are enabled.

Now, let us verify the receiver functionality with the popular HDSDR application for Windows, by following these steps:

1. Install and run the HDSDR software.
2. Select "Options | Select Input | Sound Card", since the receiver acts as a sound card device.
3. Click on "Soundcard" and select "Malahit IQ" in the "RX input (from Radio)" box.
4. Click "Ok" to confirm your choice.

To tune the receiver frequency from a computer, you will need to interface the OmniRig software with the "Malahit CAT" USB device.

1. Go into Windows Device Manager and find what COM-port device your "Malahit CAT" is associated with. This can be done by disconnecting and reconnecting the Malahit receiver. One of the COM-port entries underneath the "COM & LPT" branch should disappear and then reappear. That will be your COM-port device. It may change if you reconnect the receiver to a different USB socket.
2. Install and run the OmniRig. In the OmniRig window, configure "RIG 1" as follows and confirm your changes by clicking "Ok".

   Rig Type  = TS-480
   Port      = <your COM-port>
   Baud Rate = 19200
   Dara Bits = 8
   Parity    = None
   Stop Bits = 1
   RTS       = High
   DTR       = High
   Poll      = 500
   Timeout   = 4000
   

3. In the HDSDR, select "Options | CAT to Radio | Sync RIG1", enable "Use v1", "Sync to Rig", "Sync from Rig", "Sync LO Frequency", and "Sync Modulation" in the same menu.

The Malahit development team releases firmware updates on the regular basis, publishing them at their web site. On Windows, follow these steps to flash your receiver with the new firmware:

1. Install STM32CubeProgrammer software, which we are going to use for flashing.
2. After making sure your Malahit receiver is fully charged, turn off your receiver.
3. Press both receiver knobs. While holding them down, turn the receiver on with the power button. Release the knobs. The receiver LED should start blinking red and green, indicating that the receiver is now in the DFU mode and ready to accept new firmware.
4. Connect receiver to the computer. At this point, you should see "MALAHIT RECEIVER DFU" device in the Windows Device Manager.
5. Click the right mouse button on the STM32CubeProgrammer desktop icon and select "Run as administrator" from the popup menu to run the program with administrative privileges.
6. In the STM32CubeProgrammer window, find the drop down menu to the left of the green Connect button and select "USB" from that menu.
7. Click on the 🔄 icon to the right of the USB port name to refresh USB configuration, then click on the green Connect button. Upon successful connection, the green button should turn into Disconnect.
8. Click on the "hard drive download" icon at the left edge of the STM32CubeProgrammer window. This should bring up the "Erasing & Programming" screen.
9. Click on the Browse button and select the firmware file you would like to flash. All valid firmware files will have .BIN extension (as in "M2_FW2_10_F.bin").
10. Check "Verify programming" and "Run after programming" checkboxes. Leave the rest of checkboxes unchecked.
11. Click on the Start Programming button to proceed with the flash.
12. The STM32CubeProgrammer window will indicate the flash progress at its bottom. Once it is done flashing, the program will display the success message.
13. Once done flashing, click on the Disconnect button and the receiver should reboot into freshly flashed firmware.

The Malahit receiver is essentially a little computer containing multiple digital components, such as CPU, display, and the touch screen. Since all these components operate by using digital signals, they all generate their own electromagnetic noise affecting reception. In this section, we will go over common interference sources inside the receiver and how to deal with them.

The touch screen noise mostly occurs in shortwave bands and manifests as a constant buzzing sound that becomes louder when you touch the screen. The best way to deal with it is by moving your antenna at least several meters away from the receiver. If this is not possible (when using a telescopic antenna for example), you can temporarily disable the touch screen by pressing and holding the smaller knob for a few seconds. You will still be able to tune the receiver by using knobs. Press and hold the smaller knob again to reenable the touch screen.

The display noise usually occurs in the VHF and adjacent bands. It manifests as prominent "bumps" or "spikes" on the panorama display, often obscuring useful signals. Once again, the best way to deal with it is by moving your antenna at least several meters away from the receiver. If this is not possible, reduce the display noise by going into the RADIO menu and enabling the EMI Reduction option. This will slow down display updates, reducing the interference, at the cost of making the touch screen more sluggish. Finally, you can temporarily disable the display by clicking the power button. You will still be able to tune the receiver by using knobs. Press the power button again to reenable the display.

Your antenna choice will always depend on the frequencies you would like to receive and the amount of radio interference at your location. In this section, we will go over some available options.

The receiver comes with a short telescopic antenna that can be used at a wide variety of different frequencies, as long as you do not have any strong electromagnetic interference sources nearby. Possible interference sources include power supplies, phone chargers, LED lights, refridgerators, air conditioners, water pumps, and other devices.

The stock telescopic antenna is not the best choice in the LW, MW, and SW bands (<30MHz), but can still be used there. To improve the reception in these bands, go to the RADIO menu and enable the SW antenna option to go into the high-impedance (Hi-Z) antenna mode. The ANT indicator at the top of the screen will go green while this feature is on. The Hi-Z mode is automatically disabled at higher frequencies, where it makes no difference. You may also want to enable the PREAMP option for additional signal amplification, at the cost of more noise.

Other telescopic antennas can also be used with the receiver. They all work approximately the same, with longer antennas being more sensitive at lower frequencies. More expensive telescopic antennas are made of sturdier materials and offer better articulation. Some popular choices are Comet SMA-W100RX2 and Diamond SRH789. Some antennas come with BNC connectors and will require a BNC-to-SMA adapter to attach to the receiver. Whatever telescopic antenna you choose, keep in mind that heavier antennas put more strain on the SMA connector and may eventually damage it. You may also want to consider using a cable in order to keep the antenna away from the receiver. This reduces both the mechanical stress on the connector and the interference from receiver's internal circuitry, such as touch screen.

The optimal length of a telescopic antenna should be close to 1/2 of the wavelength you expect to receive. For example, if you are planning to listen to the 25m shortwave band, the optimal antenna length will be

which makes good shortwave telescopic antennas rather difficult to implement. It is still possible though to attach a really long wire to the antenna connector, throwing it outside or wrapping it around a room as necessary. Shortwave radio manufacturers offer such antennas as Sangean ANT-60, Tecsun AN-05, or XHDATA AN-80, where the wire conveniently retracts into a reel. Same as telescopic antennas, long wires are susceptible to the electromagnetic interference.

At shorter wavelengths (80MHz+), it is possible to use short rubber whip antennas made for the use in walkie talkies, first responder radios, and scanners. These antennas are small, very portable, and offer decent reception in the FM, VHF, and UHF bands. Some examples are Nagoya NA-701, Nagoya NA-771, Comet SMA-501, and Comet SMA-503. It is necessary to say though that these antennas are specifically tuned for the VHF and UHF bands and thus become useless in the LW, MW, and SW bands.

As mentioned in the previous sections, the electromagnetic interference is often a huge problem when listening to the radio indoors or in urban environment. The magnetic loop antennas attempt to work around this interference by receiving the magnetic component of the signal rather than noisier electric component.

A typical loop antenna consists of one or more relatively small loops of wire connected to a receiver via a tiny transformer ("balun" or "unun"). The total surface of the wire loop determines how much magnetic flux it receives, making bigger loops more sensitive. A loop antenna is directional, with the maximum gain achieved when a side of the loop is directed towards the signal source.

While loop antennas are less susceptible to the eletromagnetic interference, they are also less sensitive than conventional antennas. Thus, most commercial loop antennas include low-noise amplifiers, requiring a power source. Some commercially available loop antennas are YouLoop, MLA-30+, and GA-450.

Malahit receivers have been modified in different ways, to improve their characteristics or make them more comfortable to use. Additionally, there are people offering accessories made specifically for these receivers. In this section, we will go over some of these accessories.

Since the receiver comes with a female SMA connector, it requires an adapter for connecting BNC accessories. Using a heavy BNC adapter may damage the stock SMA connector. Fortunately, there are slim BNC adapters on Amazon, among other places.

The micro USB socket inside the receiver is soldered directly to the circuit board and may eventually break off because of the repetitive stress. To avoid this problem, consider using a magnetic USB cable, available from many sources at Amazon and other ecommerce sites. These products consist of a tiny insert that plugs into the micro USB socket and a special cable safely attaching to that insert by magnetic force.

Nikolay makes better encoder knobs, as shown below. At the time of writing this text, these knobs cost 14 euros when shipped from Russia to the EU, 17 euros when shipped to the US. You can contact Nikolay by emailing him in English or Russian. Similar, but less impressive knobs can be obtained from Amazon and other online shops.

Serhii produces custom Malahit receiver stands made of stainless steel, as shown below. At the time of writing this text, these stands cost 40 euros when shipped from Ukraine to the EU, 44 euros when shipped to the US. You can contact Serhii by emailing him in English or Russian.

While the receiver does not have built-in Bluetooth interface for connecting wireless headphones, an external Bluetooth transmitter can be purchased on Amazon, among other places, and plugged into Malahit's audio output. For convenience, attach it to the back of the receiver with a piece of Velcro.

Vladislav (R6FDF) makes active ferrite antennas for superior reception in LW, MW, and lower SW bands. The ferrite antenna works much better than the stock telescopic antenna at these bands, especially when used inside buildings and other noisy environments. The antenna attaches to the top of the receiver and plugs into the SMA socket. Malahit-DSP2 receivers will power the antenna using the bias tee. You can contact Vladislav by emailing him in English or Russian.

Theo (SV2CZF) designs and builds a variety of small, highly effective antennas, including MWA30, TWA30P, and SAR32M. These antennas have proven to work very well with the Malahit receiver, as seen in the SAR32M review by Manuel Maliszewski. You can contact Theo by emailing him in English. Theo also has a Facebook group where he posts news about his products.

This section will cover Malahit receiver modifications and repairs.

Inside the receiver case, there is a block of DIP switches. These switches control experimental firmware features that have not yet made it into the on-screen user interface:

• DIP2 -- Safe Power-On Sequence
  With this switch enabled, the receiver will only turn on after you click the power button three times. This is done to prevent random power-ons when something accidentally touches the power button.
• DIP3 -- Higher Display Frequency in WFM Mode
  When this switch is on, and the receiver is in the WFM mode, it will run the display at higher frequency. Lower display frequency will be used when this switch is off.
• Other Switches
  Please, do not touch any other DIP switches, as this may interfere with the normal operation of the receiver.

To extend operating time, you can put two 18650 lithium cells into your receiver. Some receivers even come with a battery holder fitting two cells. If your receiver has a single battery holder, you will have to replace it with a dual type. Since the receiver expects single cell voltage, your battery holder should connect cells in parallel. Do not connect cells in series, since it will damage your receiver.

It has also been reported by multiple Malahit users that the cells may touch and short encoder pins inside the case. While this does not cause spontaneous combustion, the encoders may stop working as result. Make sure your cells do not touch encoder pins and bend pins away if it happens.

To avoid power drain and excessive heat...

1. Always use the same exact cells, same model, from the same manufacturer, preferably from the same batch.
2. Before placing cells into the receiver, make sure to fully charge both cells, with external charger if necessary.

Manuel Maliszewski provides more information on connecting and managing two 18650 cells in his blog. He is also suggesting the best 18650 cells to use.

The SMA connector or the cable connecting it to the receiver board may break after a lot of use. If this happens, the replacement part is as follows:

150mm SMA-to-MCRF Cable		100mm SMA-to-MCRF Cable
MOLEX 0897629524		MOLEX 0897613412

If an encoder starts skipping or even going backwards when rotated, consider putting a few drops of alcohol into it, to clean the encoder. Remember that by cleaning encoder with alcohol, you also remove some of the grease that prevents surface oxidation inside the encoder. Hence, once the alcohol evaporates, put some silicon oil in. The oil will protect contact surfaces from oxidation on contact with the air.

CAIG produces a line of DeoxIT products for cleaning and libricating mechanical encoders and switches. DeoxIT F5 can be used for flushing and lubrication, while DeoxIT D5 will also remove oxidation and corrosion. Finally, for adding tactile feel, apply DeoxIT FaderGrease after using either of the cleaning products.

If one or both of the encoders stop working, open the receiver and check if their leads are touching any of the 18650 cells. While not dangerous to the cells, this will effectively short encoder leads, preventing encoder from working. If this happens, insulate the leads or simply bend them away a little.

The mechanical encoders used in the receiver are known to wear our and break over time. If any of your encoders break, the replacement parts are as follows:

Frequency Encoder		Volume Encoder
BOURNS PEC11R-4020K-S024		BOURNS PEC11R-4220K-S024

The only difference between these two parts is that the volume encoder will click when rotated.

This section contains links to documentation, software tools, and general reference databases.

• The Official MalahiTeam Site
  Order Malahit receivers, download official firmware and documentation.
• MalahiTeam YouTube Channel
  Guides, tutorials, and new product announcements.
• Manuel Maliszewski's Blog
  Many modifications and accessory reviews.
• David Zantow's (N9EWO) Blog
  Tips, modifications, and suggestions. History of firmware changes and a deep dive into Malahit hardware.
• Emil's Blog
  Malahit hardware and firmware information and hacks.
• Ash Nallawalla's Blog
  Detailed guide to connecting Malahit to a PC.
• Discussion Group at Groups.io
  Community of Malahit users supporting each other.

• OmniRig CAT Control
  You will need this software in order to control Malahit from a Windows computer.
• Virtual Audio Cable
  This software creates a virtual "audio cable" for connecting SDR receiver apps to digital decoder apps on Windows.
• HDSDR
  SDR receiver for Windows that supports any SDR hardware implementing ExtIO DLL API. It also works with wideband audio sources, such as Malahit.
• SDRSharp (aka SDR#)
  SDR receiver from AirSpy. This application is written in C# and runs on Windows. It is made to support AirSpy's own SDR products, but will happily work with Malahit. When connecting Malahit to SDR#, make sure you identify it as a "FUNcube Dongle Pro+" device to access the whole 192kHz spectrum.
• SDR++
  Simple, open source, cross platform SDR receiver that runs on Linux, Windows, and Android.
• CubicSDR
  Open source SDR receiver that primarily runs on MacOS, but also supports Linux and Windows.

• MultiPSK Digital Modes Decoder
  Universal decoder for many different digital communication types. The user interface is somewhat complex though.
• FLdigi Digital Modes Decoder
  Another digital communications decoder, with easier user interface.
• WSJT-X FT8 Decoder
  The FT8 digital mode decoder for simple long-range HAM communications.
• GridTracker Interactive Map for WSJT-X
  Run this software with WSJT-X to plot sources of received FT8 messages on a map.
• MMSSTV Slow Scan TV Decoder
  Decoder for the "slow scan TV" digital mode used by HAM operators to transfer images.
• PDW POCSAG Decoder
  Decoder for POCSAG and FLEX messaging protocols used by pagers, still popular in hospitals and for automated status reporting.
• DSD+ Digital Radio Decoder
  Decoder for a variety of VHF/UHF digital radio protocols, such as P25, DMR, NXDN, and more. The software is closed source, but there is an open source fork available.

• Tuning from 0 to 30MHz
  The detailed explanation of frequencies and signals found at the lower side of the spectrum, in LW, MW, and SW bands.
• QRZ HAM Callsign Database
  Address book of HAM operators around the world, searchable by call sign.
• QRZCQ HAM Callsign Database
  Another address book of HAM operators, searchable by callsign.
• Shortwave Radio Frequency Schedule
  Index of shortwave broadcasters, with frequencies, times, and locations. Search by station name, frequency, band, or time.
• Shortwave Schedule
  Another searchable index of shortwave broadcasters. Search by station name, frequency, or see currently transmitting stations.
• Radio Locator
  Searchable index of AM and FM stations closest to your location. Only works for US locations though.
• Signal Identification Guide
  Visual guide to radio signals, for identifying modulation types and signal sources.
• RadioReference
  Forums, frequency database, trunked radio information, and FCC license data.

Compiled and maintained by Marat Fayzullin
Translated to Russian by Victor Shulzhenko
Proofread by Sergey Belikov