Soft66LC4 SDR – initial impressions

I received a Soft66LC4 SDR receiver for evaluation. The review of this radio will be in 3 parts, initial impressions, usage test, and full technical test. Here are my initial impressions.

The Soft66LC4 is the newest SDR receiver from Kazunori Miura JA7TDO. There have been several revisions of this inexpensive



SDR over the last couple of years. The evaluation unit came in about a week from Japan in a plain envelope with no documentation or software. You are expected to refer back to JA7DTO’s website for help. Although the setup is a bit complicated, it wasn’t too bad for me since I deal with a lot of control software that uses USB-to-serial connectivity. I was pleasantly surprised to find out that my Dell laptop’s internal sound card can process at 192khz, giving me a full 192khz of visible bandwidth.

The Soft66 is a bit larger than an Altoids tin. JA7TDO’s eBay store states that you have to finish the case yourself and drill holes, but it seems that he is doing this for you now. There is an SMA antenna connector, a mini USB port, and an indicator light on one end. On the other end is a 3.5mm audio jack, and a hole for access to an adjustment pot for RF gain. I found that my sample needed a slightly longer mini USB plug as the first one I tried did not stay in well.

Driver installation can be quite complicated but I intend to help him with this by writing up some easy-to-follow instructions. One issue that exists with this SDR for now, but will probably be resolved soon, is that there isn’t a way to control the SDR with WinRAD yet. You have to use the separate control application which makes the process a bit clunky. I believe that once more of these newer LC4 models are out there there will be support for WinRAD and other SDR Applications, as there were for the previous Soft66 radios.

Initial usage tests at my location were favorable, considering my lack of a decent antenna (about 10M of wire in a tree outside my window), and excessive RFI at my location.  I hope to get out to a more remote site to perform the detailed usage review in a more interference-free environment.  Coverage is from 500 khz to 70 Mhz.  For now, the control app does not warn you if you enter a frequency outside that range, but simply crashes.  Luckily, this does not lockup the controller, and you simply need to relaunch the application.  I was able to receive MW AM stations, CW, SSB, data, and AM on the amateur bands, and plenty of SW BC.  I did not try WinRAD’s DRM feature yet.

I’ll try to get this set up for remote access if possible, but for now, with no way to control it other than with the supplied application, I will hold off.  Special thanks to Kazunori Miura for supplying the test sample so quickly, and to my friend WA2CDL, who offered to perform the technical testing.

On JA7TDO’s eBay store these radios sell for $108 plus shipping, and are fully assembled. Well worth the money as long as the proper DLL files are made available for using it with WinRAD. A more extensive test will follow.

eBay store link:

Soft66 page:

–Neil W2NDG

Neil Goldstein, W2NDG, is a regular contributor to and writes from New York, USA. Contact him at [email protected].

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