Based on the popular SDR transceiver 'SunSDR2-Pro', Russian manufacturer Expert Electronics offers the 'SunSDR2-DX'. This transceiver works as a Defined Radio (SDR) direct scanning software with a 16-bit high-resolution A/D converter. All amateur radio bands from 160 to 6m and the 2m VHF band are supported. The transmission power is 100W on the short wave, 50W on 6m and 7W on 2m.
The increased transmission power requires a larger final stage and therefore a larger housing than the SunSDR2-Pro. At the same time, the thermal concept has been modified, resulting in a reduction in overall heat production. An external fan is provided, which can be mounted on top of the large cooling fins of the case if necessary (continuous operation in the context, very hot environment). Further changes to the "Pro" relate to filtering possibilities. A new 100 MHz high-pass filter is available, leading to the VHF for better sensitivity. For the HF, there are still 9 single band pass filters or a single low-pass filter starting at 65 MHz. This combination is complemented by a permanently inserted low-pass filter starting at 70 MHz, which improves the dynamic range on short and 6m waves.
The SunSDR2-DX receiver is based on the fast 16-bit LTC LTC 2209, which runs at 160 MS/s. The receiver is equipped with a 70 MHz low pass filter. This gives you an excellent dynamic block range of up to 130 dB. The aforementioned 9 short wave passfilters result in a receiver that is a very large stable signal with excellent sensitivity and a high dynamic range. Along with ExpertSDR software, two independent main sub-receivers and two independent sub-receivers in the same bandwidth range are possible. In addition, you can display a wide spectrum up to 80 MHz.
The transmitter is designed completely independent of the receiver with its own square oscillator and thus allows for flexible operation half or full duplex. Thus, the SunSDR2-DX can also be used as a measurement and spectrum analyzer with appropriate software. Independent release stages for short waves and VHF generate a transmission power of 100 (6m: 50) or 7 watts. For short waves there are two switchable antenna connections, the connection to the VHF is designed separately. Other connections are intended for cross-operation or the connection of a final stage. Eight freely programmable switching outputs allow automatic selection (depending on frequency) of antennas or external band filters or the connection of external preamps and sequencers.
New is a connection for an external tuner! In the future, the manufacturer plans to offer a proper automatic tuner that can be controlled via this connector.
Another special feature is that the fast FPGA of the transceiver processes the key signals of a Morse key directly on the device. This makes it possible for the transmitter to be typing without significant delays, and QSK can also function at higher speeds. A microphone can also be connected directly to the radio. Here the transceiver also has two sockets, an RJ45 socket to connect a Yaesu hand microphone and a 3.5 mm jack socket, for example from a headset microphone. The decoded audio signal is emitted locally through a very low distortion 24Bit DAC at a headphone output, as well as digitally transmitted to the computer. This opens up many possibilities for use directly in the shack or as a remote-controlled transceiver.
SunSDR2-DX is connected to the computer via an Ethernet port. Clever programming enables a direct connection between transceiver and PC and integration into the home network via switches or DSL routers. The ability to remotely control the SunSDR2-Pro completely via LAN is particularly convenient. In addition to connecting to the device itself, the NF is also transmitted digitally and therefore allows the operation "on the couch", for example with a simple PC headset.....
A 10 MHz input for a reference clock replaces the internal OCXO signal, which also offers excellent ± stability; 0.5 ppm.
The free ExpertSDR software is in continuous development and will always be available for free to the owners of the transceiver in the future. Windows XP, Win7, Win8, and Win10 operating systems are supported, and there is a port for MacOS and Linux. The operation of the software is relatively clear and also offers functions for the operation of the competition or integration with multimodal programs, for example for RTTY or PSK31. A virtual CAT interface allows the use of other programs, for example for the competition.
SunSDR2-DX is the next logical development of Expert Electronics' SDR transceiver success.
This new hardware, along with the ExpertSDR2 software, has steadily improved over the years, demonstrating that this manufacturer is a serious competitor in the market and in long-term plans. Thanks to the compact size of the SunSDR2-DX of 190 x 170 x 80 mm and weighing about 2 kg, it is suitable not only for shacks, but also for portable use and for holidays (power 8-14.8VDC, max. 24 A).