The AFEDRI SDR-Net is produced by Alex Trushkin, 4Z5LV. It is a direct sampling SDR with a 12-bit 80MHz ADC that covers 0.1 to 30.0 MHz. It supports both USB and Ethernet interfaces, and can be used with Winrad, Linrad, HDSDR, CuteSdr, Sdrdx and SDR-Radio/SDR-Console software. It can record up to 1.25 MHz bandwidth to disk for later playback and analysis.
The SDR-Net X2 version has two receiver boards with the same clock. The receivers can be operated separately, on adjacent frequency segments, or phase-locked together on the same frequency with different antennas. It offers 900 KHz bandwidth per channel.
SMA antenna connectors LEDs, power, USB, Ethernet
The SDR-Net is simple to set up for ehternet network operation. The network mode allows it to be more easily used with a variety of computers, operating systems, and SDR software packages than does the USB mode. For review purposes, I was using SDR-Radio, version 1.5, build 1058. It recognizes the AFEDRI SDR-Net as a RFSpace NetSDR or SDR-IP. The image below shows some short wave broadcast monitoring in Sync-AM mode. SDR-Radio does support the RigCAT protocol, so it can be controlled from digital decoder software like fldigi.
Alex also provides a modified version of CuteSDR that works with the SDR-Net. I have compiled this on Fedora Core Linux x86_64 versions FC15, FC16, and FC17. A screenshot of it running under FC17 is shown below.
Direct sampling SDRs give up approximately 6 dB of dynamic range per bit reduction in ADC resolution. So theoretically, this radio has 24 dB less dynamic range than the QS1R, or 12 dB less than the SDR-IQ. But the AFEDRI is 1/4 the cost of a $1K QS1R and 1/2 the cost of a $500 SDR-IQ. While I can tell the difference between it and the QS1R, the AFEDRI SDR-Net is as sensitive and selective as my Ten-Tec RX-320s and sounds as good or better than them and many other more expensive modern and boatanchor receivers.
The AFEDRI SDR-Net ($259 USD) and SDR-Net X2 ($389 USD) are well worth the price. (price as of Oct 2013)