Afedri SDR-Net 2.3a Review

Support and Documentation
The documentation for the Afedri SDR-Net is available on the shipping CD or from Alexs’ website. The documentation covers most operational aspects of the Afedri SDR-Net in a very basic format. There is also a basic example of how to get the Afedri SDR-Net going with HDSDR. Support for the Afedri SDR-Net is excellent through a couple of resources. First of all,  you can email Alex directly with questions and he usually responds fairly promptly. The other method is to go to the Afedri SDR-Net Yahoo Group. There is a great deal of information on the Afedri SDR-Net located in the Yahoo Group. Chances are good if you have a question or problem, you can find the answer by searching this group. Since Alex is continually improving on the Afedri SDR-Net, you might want to keep an eye out for new firmware upgrades that come out occasionally. Upgrading the firmware is fairly easy to do and covered in the documentation. When you look at the manual covering the firmware upgrade section, you may get the impression that you have to open the Afedri SDR-Net and change a jumper. If you keep reading, you will see that this is not the case. You just will need to load the Control Box Software and go to the About tab. Clicking on the Firmware button will put the Afedri into the Firmware upgrade mode which will be noted by the configuration of the leds (Red and Blue On and Yellow Off). Once the Afedri is ready to receive the new firmware which you downloaded from Alexs’ website, you will use a utility program called tftpd32.exe (included on the shipping CD) to push the new firmware to the Afedri SDR-Net. Actually its’ pretty easy once you have done it once.

In Use
Let’s just say that the Afedri SDR-Net was a real pleasure to use. The test antenna we used was a 20Meter dipole. The Afedri SDR-Net was used with SDR Radio.com V2, HDSDR, and Studio1 and played nice with all the SDR software packages. Once again, Studio1 was our favorite SDR software package to use with the Afedri SDR-Net and provided the best SDR performance / experience in our opinion. We noticed very little difference in performance in using the USB connection versus the Lan connection with the exception of the reduced bandwidth of the USB connection. Again for SDR hobbyist that might be looking for a SDR radio that is very easy to set up and use, the Afedri SDR-Net connected via USB using the SDR Radio.com software is simple as it gets. We feel that this is a huge plus for the Afedri SDR-Net. Setting up the Lan interface make take a little more time and knowledge, but actually its pretty easy and well worth the payoff for the extended bandwidth.

Most of our receive test was done with the FE Gain control set to between 1.0 to 1.6 and the VGA gain control set around set around 17 dB which seemed to be about right for our environment. . These settings gave us a good ratio of noise floor to signal strength balance, Depending on your antenna / environment setting the gains very high may cause front-end overload in the presence of very strong signals, so use only what you need.The FE gain can be set as high as 4.00 and the VGA Gain can be set as high as 35.00 dB. However, Alex recommends for most users to keep the FE gain between 0 to 1.6 and the VGA gain around 11dB to 15dB. Overly increasing the gain can lead to ADC overload and nonlinear IMD levels. Sensitivity compared very well to our reference Yaesu FT450D conventional ham transceiver if not a good bit better. However, when coupled with all the advantages that the SDR software software offers, the Afedri SDR-Net was the clear winner when it came to digging out the weak signals. Of course nothing beats having a big display showing all the signals in the band you are monitoring. The Afedri SDR-Net would make an ideal candidate for an inexpensive pan-adapter for your conventional HF rig (we will be publishing a future article on how to do this through software with the Afedri SDR-Net).

During our many hours of listening using the Afedri SDR-Net with shortwave broadcasts, amateur radio sideband, amateur radio CW, amateur radio data, and even local AM stations we noticed no issues with front-end overloading or ghost signals. We were able to very easily isolate weak signals close to more powerful signals with no bleed-over from the stronger signal when using Studio1, SDR-Radio.com or HDSDR. Our lab environment is located in a very rich RF environment, but we did not notice any problems with RF degrading the performance of the Afedri SDR-Net. This has been a problem for some of our past SDR radios. We also located the Afedri SDR-Net a few feet away from our test computer and did not notice any unusual amount of RF interference from our test rig. As we mentioned earlier the Afedri SDR-Net was dead on frequency for us in all the SDR software packages. As is common with most direct sampling receivers we noticed no issues with a large center spike which can be found in most sound-card based SDR radios. The Afedri SDR-Net does have one, but it is very tiny and barely noticeable with no antenna plugged. The Afedri SDR-Net is basically a very all round solid performer for its price class for HF reception.

Conclusion
As we stated before that Ham Radio Science user reviews are based on the following categories, value, ease of use, how well it works, and customer support. The Afedri SDR-Net ticks all these boxes in spades. We started off looking for a good budget HF SDR radio and expected some short comings, but we were pleasantly surprised by what the Afedri SDR-Net had to offer. We believe that for the $249 price point the Afedri SDR-Net offers an incredible value for its price point for a network connectible HF SDR radio with a very large useable bandwidth. Alex was also a pleasure to deal with on answering questions for us. We think it is safe to say the Afedri SDR-Net is currently in a league of its own and highly recommended.

Afedri SDR-Net
Price $249 (with case) + Shipping