F.A.Q. is self-explanatory, we collected frequently asked questions and presented answers to them. In time F.A.Q. will grow bigger.

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1. Make sure you've installed the ExpertSDR2 version for your device. Each device has a special version of the ExpertSDR2, other versions of ExpertSDR2 won't work with your device and may ruin it.

2. Add ExpertSDR2 in the Windows Firewall exceptions list for both Private and Public networks or just disable Firewall and your antivirus software.

3. Check that AnyDesk doesn't block the ports which are used by the ExpertSDR2/3 – 50001 and 50002. The procedure is explained in the above section ExpertSDR2 software-> question#1. ExpertSDR2 always uses two ports for each radio; one is indicated in the Options-> Device menu-> Expert tab and +1 e.g.: 50001 (indicated) and 50002.

4. Make sure your PC/notebook has a fixed IP address with sub-net 16 e.g.: Your PC/notebook should always be in the same subnet with the radio, otherwise you won’t be able to use it.

5. For the first run you need to connect the radio directly to your PC with Ethernet cable. When you make sure that PC and radio are in the same sub-net you can connect your radio to the router.

6. Run ExpertSDR2, open Options-> Device menu-> press the Discover button.

7. In the new SDR radio window press USE in front of your radio.

8. Start the radio by clicking to red Start button in the ExpertSDR2 window.

Most likely AnyDesk software monopolized the port 50001, in this case, just delete AnyDesk or delete AnyDesk then change the port in the ExpertSDR2 to 50003 in the Options-> Device-> Expert tab then install AnyDesk again.

If the above instruction didn't help, the issue is in some application that uses the same UDP-port as SunSDR2 DX/PRO/QRP/MB1. To determine PID of the application which uses the same UDP-port, open the terminal (press Windows+R, in the appeared window, write cmd, and press enter). In the appeared terminal enter the following command:
netstat -aon | findstr 0.0:PORT_NUM
example: netstat -aon | findstr 0.0:50001
result: UDP *:* 2740
If there is no application that uses this port, then the terminal won't give you any result.

To determine application name by PID write the following command in the terminal:
tasklist /svc /FI "PID eq PID_NUM"
where PID_NUM is PID of the application, which is given by the previous command
example: tasklist /svc /FI "PID eq 2740"
If there is another application that uses the same UDP-port as SunSDR2 DX/PRO/QRP/MB1 just change the port to the available one.
Probably your Firewall or other antivirus software blocks data exchange between PC and the radio. Short data exchanges do pass through, like SDR info, but large pieces of data are considered a threat. Add ExpertSDR2 software to the exceptions list in your antivirus software.
Currently, all our devices have one ADC, thus you can use only one antenna input at the same time for RX mode.
ExpertSDR2 supports two independent software receivers, which can use different antenna inputs, but cannot receive at the same time. Each receiver (RX) has its own separate panorama, set of settings, and can use different modes. In case third-party software does not support TCI, each RX has its own independent CAT and VAC interfaces. The second RX can be viewed in a separate window on the second monitor. Each RX has two SubRXs.
Each of SubRXs has independent volume and balance controls, any of them may be selected for transmission. You may use up to four "slices" simultaneously.
No, each transceier has two software receivers, but one ADC, you can use both receivers to work either in hte first 0...80 MHz or the second 80...160 MHz Nyquist zone of the ADC.
You can transmit on the 4M band via low power output (DAC OUT), max 10mW. To get more power you can use an external power amplifier. To RX on this band use direct input/output of high-speed ADC/DAC. In case of MB1, for comfortable RX operation connect a narrow pass filter to the RX IN.
You can operate on the LW band. To receive signals above 9 kHz you can use HF antenna connectors. For TX use DAC OUT, because the internal HF power amplifier doesn't work on these frequencies.

The S-Meter shows the signal level in the RX filter bandwidth.

When no antenna is connected, the S-Meter shows the level of the radio's internal noises.

The readings depend on the filter bandwidth, if you set SSB mode with 3 kHz bandwidth, the readings will be at the higher level, if you set CW with 100 Hz bandwidth, the S-Meter readings will be lower.

The radio's internal noises also depend on the Preamp level (sensitivity). If you set -20 dB ATT, the sensitivity will be at its worst and S-Meter readings higher, if you set Preamp +10 dB, the sensitivity will be higher and radio's own noises will be at their lowest.

S-Meter in the ExpertSDR2 has two different calibrations for HF (0-30 MHz) and VHF (30-300 MHz).

HF and VHF signals with the same dBm level have different S-scale values.

You can find calibrations tables for HF (Table 3) and VHF (table 4) at the following link http://hamwaves.com/decibel/en/

For example:

29 MHz -127 dBm ~ S0.5 (preamp on)

52 MHz -127 dBm ~ S3.5 (preamp on)

To verify you may connect a signal generator to an antenna port and compare the generator signal with the S-Meter readings for all S-levels, compare to tables from the link above.

Also, you can see the IARU recommendations for HF and VHF S-Meter calibration at the following link https://en.wikipedia.org/wiki/S_meter
For HF S9 = -73 dBm = 50 uV (50 Ohm), for VHF S9 = -93 dBm = 5 uV (50 Ohm).

S-Meter in the ExpertSDR2 corresponds to the IARU recommendations, each device is calibrated at the factory during manufacturing.

SunSDR2 Q9
1. Noise level on the spectrum scope depends on its resolution. Divide panorama sample rate (in Hz) by the FFT size (in the Spectrum settings) you'll get the minimum FFT bin band - let's call it "single-unit filter". The whole panorama consists of such single-unit filters. Each such filter displays resulted power in its own band and this power is displayed as a point on the panorama. A spectrum line is drawn based on these points. If there is a strong useful signal, with a high signal-to-noise ratio, inside the single-unit filter, then panorama and S-meter readings will be the same. As a rule, it applies to monochrome and/or narrowband signals like CW or PSK, e.g. someone's tone signal. If there are no useful signals, then will be displayed the noise power in the filter bandwidth.
2. S-meter displays summed signal power in the filter bandwidth. i.e. a sum of useful signal and noises in the bandwidth.
Let's look at the noise receiving:
Sample rate 156250 Hz. FFT size 16384 (max). SSB filter bandwidth 2.9 kHz, noise level on panorama -118 dBm. A receiver receives air noise.
Note: Approximate readings from the screenshot - RX mode.
Task: calculate S-meter readings.
Note: Let's agree that these readings are unknown to us.
Step 1. Let's calculate the FFT bin band (single-unit filter). 156250/16384 = 9,53 Hz. This is the bandwidth of a single-unit filter.
Step 2. Let's calculate the difference between RX filter bandwidth and single-unit filter. 2900 Hz / 9,53 Hz = 304 (times). Filer bandwidth is approximately 304 times wider than a single-unit filter.
Step 3. Let's calculate the difference in dB between summed noise power in single-unit filter bandwidth and summed noise power in RX filter bandwidth. 10*log(304) = 24.8 dB. i.e. noise power in 2.9 kHz bandwidth will be higher than in single-unit filter on 24.8 dB.
Step 4. Let's calculate S-meter readings. -118 dBm + 24,8 dB = -93,2 dBm.
Approximate S-meter readings will be -93.2 dBm.
Conclusion: as you see, the calculated value of the S-meter readings is equal to real readings on the screenshot. The difference is 1 dB, it could be explained by the fact that the noise level slightly differs from -118 dBm, we assumed from the screenshot.
If there is a useful signal in the RX filter bandwidth, e.g. SSB signal, S-meter will also display the summed power of all voice components in the filter bandwidth. On panorama, each separate voice component will be displayed lower than overall S-meter readings. This statement is also valid for TX mode.
Note: If you are in CW, with filter bandwidth 20 Hz, sample rate 312 kHz, and FFT size 16384, S-meter readings and panorama noise level will be approximately equal.
S-meter values and audio level have program compensation when you use the attenuator because the signal level on the antenna input is always the same and doesn't depend on the attenuator level. With this solution, a user doesn't need to calculate real values on his own, every time when the -20-dB attenuator is used. Also, he doesn't need to adjust AF or RF level every time when the -20-dB attenuator is used, like in most classic transceivers.
Attenuator influences only receiving dynamic range, S-meter and audio level stay the same. If you disconnect the antenna you can see how the receiver’s noises are changing when you switch the ATT. The receiver's noise level is lower when you select ATT 0 dB, which means that RX sensitivity is higher. When you select ATT -20 dB, it means that the RX noise level is higher, but RX sensitivity is worse. It is done in the hardware.
High-speed ADC in the TRX simultaneously receives several Nyquist zones, 0-80 MHz, and 80-160 MHz. Signals from different Nyquist zones overlay each other as image channels. For example, 15 MHz on HF is reflected on 145 MHz. For ADC to avoid HF stations when operating on VHF, we installed SAW filter with pass frequencies 144-148 MHz. Also, there is another VHF wideRX bandpass filter: 95-155 MHz (Butterworth - 5 Order) for the whole 2nd Nyquist zone.
VHF SAW filters final attenuation for HF frequencies is around -60-70 dB. For example, there is an S-9 station on the 20M band, you'll see it on VHF as an S-1 station or lower. If you want to completely attenuate HF stations, you can install the additional HPF we manufacture for the MB1, with 100 MHz cut frequency. From our experience, HF stations can be received on VHF 6-15 dB above the noise floor, depending on the VHF antenna quality. Good VHF antenna is an additional band filter. If you'll receive VHF stations on an unmatched HF antenna (as an experiment), you'll see that AFC of the internal filter will be corrupted and attenuation of HF stations worsened.
Nominal (PEP) HF output power of the MB1 and SunSDR2 DX is 100W and for SunSDR2 PRO it's 20W. For 100W in SSB mode it might differ from 30 W up to 80 W. The reason for that is peak-factor, it equals 3 for voice signals. TONE signals have constant output power 100 W. Voice signals with peak power of 100 W have real power approximately 3 times lower. To increase the real power of voice signals use the compressor and other features in the TX processing module.
Yes, you can. Ext CTRL switches in the MB1/SunSDR2 DX/SunSDR2 PRO are open collectors and can give you either open line or shorted to ground lines.
If you want to get TTL level 0V or +5V (+12V), you should tie serial resistors 1-10 kOhm.
When the switch is on - it gives logical "0", when off - logical "1". You can adjust the Ext CTRL table for the required band combination.
If you need 5 V TTL levels, you can use 5V zener diode from each line to GND and put resistors with diodes into Ext CTRL connection box.
Max signal level on the receiver's input is (enabled АТТ -20dB) ~S9+100dB on the S-meter scale, which is approximately 4.5V of HF voltage peak-to-peak. A 1000W station may be in 10-20 meters from you and receiver will still function properly.
MB1/SunSDR2 DX/SunSDR2 PRO and ExpertSDR3 have two independent software RXs, which can be used by one or two operators. So yes, the 1st operator can receive and the 2nd operator can transmit, but to do that we should implement the Duplex mode on the firmware level.
The current hardware of our transceivers supports Duplex mode. When you transmit with one antenna connector (A2 or A3) the other one can be used for RX mode, either on one band or on different bands.
At this point, the Duplex is not implemented, while you transmit on the 2nd RX, receiving on the 1st RX will be blocked.
To TX you'll have to make some tweaks in ExpertSDR2.
Via low power output (DAC OUT) you can transmit on: 0.1kHz - 150MHz with maximum power of 10mW.
- Harmonics may appear while transmitting out of amateur bands.
- I have to mention that, we can not guarantee the proper functioning of our devices with changed parameters and we are not responsible for the customers transmitting on the frequencies out of HAM range, this could be done only with the proper license.

To RX on these frequencies, we'll recommend to us the ADC IN because standard antenna inputs will have low sensitivity.
Maximum allowed signal level on the ADC IN connector is 0.3V of the active voltage (RMS). Do not exceed it, it may result in the transceivers overload and ADC fatal damage.

ADC cannot receive DC, receiving available from 9 kHz and higher, never tested below 9 kHz.
RX below 100 kHz will have low sensitivity, we've never tested our devices on these frequencies.



The maximum panoramic resolution requires a lot of CPU resources. Not all PCs are able to process all data, so this leads to sound issues.
We recommend lowering panorama resolution if at higher sample rates your PC has sound issues.
DIGL/DIGU modes are identical to LSB/USB, the only difference is that tuning frequency is shifted by the offset value relative to 0 Hz by LF. User can manually set this value in Options-> Device-> TX-> DIGL/DIGU-> offset.
It was done for comfortable tuning on digital stations by the mouse click on the ExpertSDR2 panorama.
The ExpertSDR2 software separates the radio signal of the DRM station, then passes it to the third-party software (Dream DRM, WIN DRM, etc.) for decoding via VAC (Virtual Audio Cable).
Bandscope has its own DDC software receiver in the radio's hardware, it works in parallel with the main receiver.



When you operate in DIGI modes you need to carefully adjust VAC gain. In this case you need to adjust VAC gain for TX mode (Options-> Device-> VAC-> Receiver1(2)-> TX Gain). Also, we recommend setting Mic level indicator and control the signal level. DIGI modes signal should be around -3...-1 dB.

Note: TX Gain parameter might be either negative or positive, depending on whether you want to amplify the VAC signal or attenuate it.

Transceivers are supposed to operate with loads around 50 Ohm impedance. This is one of the main requirements.
From our experience, antenna SWR may rise up to 4...5 for RX mode without a significant drop in receive quality. For TX we do not recommend going above SWR 1.7...2.
For the X8 switch to work properly, enable the РА button in the ExpertSDR2 software.
You hear HF crosstalks of the transceiver on the PHONES jack and crosstalks detected on nonlinearity of the schematic. Try to use ferrite beads with transparency 1000-4000 on the coax cable of the antenna and Mic cable. Make 5-10 winds of cable around the bead.
As a rule, this effect happens because of the HF current on the cable surface (instead of inwards). These crosstalks also may cause feeding of an external PA, so they should be eliminated.
If your transceiver is connected to the router directly then you can find it in the router's ARP list. Find the transceiver's IP address in the list, there will be the MAC address.
Yes, you can use a straight key, to do that, you should disable the Break-In in the ExpertSDR2 and use one of the contacts of the KEY jack. See user manual for your exact transceiver.


Select ADC IN in the ExpertSDR2, in this case the signal goes:
A1 ANT-> BPF-> RX OUT-> there you put your external BPF/ATT/PREAMP-> RX IN
There are two ways to connect an external speaker to the MB1:
1) Connect a multimedia speaker via adapter jack 3.5-6.3 to the PHONES jack on the front panel.
2) Connect a multimedia speaker to the headphone jack 3.5 on the rear panel, then open: Options-> Sound card-> Output list (first in the list). Set the Enable check box, now you can listen to the sound from a multimedia speaker.
Note: If you don't need the internal load speaker, you can disable it in the audio menu, see manual.
If you use PC's sound card via rear connector it can produce some latency. Minimal latency can be reached only via the front panel PHONES jack and internal loudspeaker.
Being the software defined radio, there is no provision for hardware generated FSK in the MB1, but from our users' experience, AFSK is better in so many ways including decoding ability, seeing bad activity and so on. When you use DIGI software in the MB1 and make a virtual audio connection, the quality of TX signal the same as in FSK.
We would recommend simplifying data operation by using the MB1's own computer for hosting the RTTY software. Also, you may run the RTTY software on the external PC and use a mic (input) and a line (output) on the rear panel to get the AFSK audio into the MB1.
Yes, the MB1 has internal protection, output power is automatically decreased if SWR exceeds the manually set in the ExpertSDR2 value 2-5.
Yes, phones and the Mic jacks can be configured for operation in DIGI modes or for voice operations if you use voice macroses from the Log. MB1 uses 2 channels for one receiver, but if you use 2 different receivers (RX1, RX2), you can adjust balance for each receiver, e.g. RX1 for the left channel, RX2 for the right channel. Yes, they are independent of the MIC GAIN and AF OUT knobs, because these inputs/outputs are used in VAC menu and have their own RX and TX gain settings, which can be adjusted by the user.
The Windows gain settings also can be used for gain adjustments, but we recommend to use only ExpertSDR2 gain settings.
*Yes, they are independent of the MIC GAIN and AF OUT knobs because these inputs/outputs are used in VAC menu and have their own RX and TX gain settings, which can be adjusted by the user.

The Windows gain settings also can be used for gain adjustments, but we recommend to use only ExpertSDR2 gain settings.

If used VAC menu, TX monitoring doesn't work.
The ExpertSDR2 software has an additional line output menu, where you can select the audio output device e.g. speaker on the front panel. It contains RX/TX signals, normally this menu is used for recording QSOs in contests, but if you need you can use it for other operations.
The rear Mic input is mono, but it is split into two channels.
*Yes, it can. When the PTT signal goes from the PTT footswitch, TX button on the front panel, TX button in the software window - will be used an audio signal from the Mic input (front panel inputs).
To set up independent audio output from the front and rear panels of the MB1 you should:
- Open Realtek HD Audio Manager (in Windows system tray) or open Control Panel\Hardware and Sound\Realtek HD Audio Manager
- Press Device advanced settings
- In Playback Device set Make front and rear output…
- Press OK
Realtek HD Audio Manager
For more comfortable use:
- Open Control Panel\Hardware and Sound\Sound
- To rename your connections, press Properties of each connection and rename it to Rear Panel and Front Panel
- This way, with selected MME driver, ExpertSDR2 will detect audio outputs as Rear Panel and Front Panel.
Control Panel Hardware and Sound Sound
Shut down the MB1, unplug, wait 2 minutes, reconnect. Double check antenna selection and settings.



The top operating temperature is 75 Celsius. When the transceiver will reach this temperature, the special protection will trigger and shut down the transceiver.
If the temperature is below 75 Celsius, it may be considered as normal.
We can recommend a power supply with +15V DC voltage and 5A current. A power supply can be either transformer or impulse.
If you prefer impulse power supply, you need to pay attention to filtering of the output voltage and presence of the filtering paths on the 220V line. It's common when distortions are created via 220V line. A power supply creates distortion and wiring act as an antenna. Filtering paths are mandatory, also we recommend to install ferrite beads on both ends of the power supply cable.
Note: Max power output is guaranteed only with 15 V power supply voltage.
You can use any PA which requires input power below 20W.
SunSDR2 PRO supports max output power correction for operation with external PAs.
It means that you can set max output power in SunSDR2 PRO, e.g. 8W and can adjust the Drive level from 0 to 100%, output power will be adjusted from 0 to 8W (not to 20W). This way you cannot damage your PA by overload on the PA input.
We can recommend HLA-150 Plus or 300 Plus.
In Tone mode, with 2% on Tone slider:
On HF (14MHz) min output power ~ 4.4 mW.
On VHF (145.5 MHz) min output power ~ 0.5 mW.
Note: These values may slightly differ in different transceivers.
Yes, it has an automatic protection of the internal PA. In parallel to each antenna connector there is a 2W 1kOhm resistor, to remove slowly accumulating static discharges in the receiver, and also to provide an SWR=20 in case of antenna disconnect.
HF/VHF output stages can operate with high mismatches, up to SWR=20, but at the same time, they get warmer. Output stages can easily endure short mismatches.
Press the L/W button once again and wait until the LED turns green.
Internal WLAN access point (standard 802.11 n) allows you to setup wireless connection between your transceiver and PC. For example, your transceiver set up at your workstation and switch to WLAN mode. Using a notebook with a built-in WLAN you can work on the air being in another room, or basically anywhere where you can reach this WLAN.
The only thing you need for internal WLAN to work is to connect a miniature antenna supplied with the module to the transceiver, that is the main difference between the internal WLAN module and an external. An external access point is a separate device with power supply and requires a cable connection to the transceiver. From the operational standpoint, both solutions are the same.
You can revert any changes done to the internal access point or transceivers IP address, by pressing the RST (reset) button on the rear panel of the transceiver. Press the RST button, then while holding it on switch on the transceiver, release the RST button. At this moment LED on the front panel of the transceiver will start blinking. You need to wait until LED will stop blinking and turns to constant green. Your transceiver is ready to work.
Note: the RST micro-button is very sensitive and may fail if you press it too hard. Be careful!



LED blinks - it means the transceiver is initializing and not ready for operation. If it constantly blinks, it means there is no network connection.

LED is stable (NOT blinking) - transceiver is ready for operation and can be connected to the ExpertSDR2.

In the SunSDR2 QRP we used an advanced stack of a local network, so you have 4 options for local operation:

1. DHCP Auto mode is set by default. It works this way: in the beginning, transceiver works in DHCP Client mode and tries to get the IP-address automatically from an external server, if it gets the IP address, LED will stop blinking, becoming stable green color. If transceiver can't get the IP address within ~20 seconds, it will automatically turn to DHCP Server mode and provide IP address, in this mode LED will become stable orange.

2. DHCP Server mode is for direct connection of the transceiver and a PC. In this case, the transceiver will provide a PC with the correct IP address, so you don't have to adjust network card settings. In this mode, LED will become stable orange. in this mode, the transceiver will also have a static IP address

3. DHCP Client is for connection of the transceiver to the home local network, where you have a DHCP-server, which automatically provides IP addresses, for example, router or ADSL-modem. In this mode, LED will become stable green.

4. Static IP, in this mode transceiver, has a static IP address, works the same as in SunSDR2PRO - in this mode LED will become stable orange. By default, IP address is This mode requires to set up PCs network card according to the same instruction as for SunSDR2PRO. We do not recommend to use this mode without special need.

Note: if you have a direct connection, after initialization process you may change a network mode to DHCP Server, this will save you about 20 seconds after switching on.



The normal operating temperature is +45...+55 C because the ADC is using the casing as a heat sink.
ColibriNANO connected to RPI3 (with our image) via USB connector, RPI3 connected to a router via LAN.
RPi3 will automatically get the IP address from a router. You'll need to set up port forwarding (5050 by default for the ExpertRS and 80 if you want to remotely control the receiver via WEB-client) from a router into RPI3 IP address, you can find the example in Paragraph#3 in the User Manual for the ExpertRemote system. Now you can use remote control.
Note: ColibriNANO is not a network device, as other our devices.



1) Connect the ColibriDDC to your PC with Ethernet cable.
2) Connect the ColibriDDC to your transceiver via CAT-system in the ExpertSDR2, using the OmniRig (Options-> CAT-> Interface-> OmniRig).
You should have installed OmniRig SW on your PC.

3) In the OmniRig settings (in the ESDR2) set the Enable checkbox.

4) Press the Configure button to open the OmniRig SW settings window.

5) All further information you can find in the User Manual-> CAT Menu.
Then you set up the OmniRig to operate with a certain transceiver via a certain COM-port.

High-speed ADC in the ColibriDDC can receive signals in 0-800 MHz range, but this range is divided into special Nyquist zones. The Nyquist zone bandwidth is 62.5 MHz. ColibriDDC can receive only in one Nyquist zone at the same time e.g. 0-62.5 MHz, 62.5-125 MHz, 125-187.5 MHz etc.
For each zone, you should use BPF, for the 1st Nyquist zone ColibriDDC has its own Low Pass Filter 0-60 MHz (Chebyshev I - 7 Order).