Over on this Japanese language blog, ttrftech has been experimenting on a type of direct sampling front end board (Use Google Translate) for a direct sampled RTL-SDR dongle. More info about his direct sampling front end can be found on this post. Translated, it appears his board has the following feautres.
- Filter x2 up to fifth order
- RF switch
- Power regulator
- Input transformer (optional)
- The RJ-45 (optional) or the SMA input connector
- Power supply to the antenna
- Output to U-FL or SMA (ipex) connector
The results seem to show his board does improve reception. Note that the RJ-45 appears to be the antenna. There also appears to be review of the board by “pup” here and a video showing the board filtering out a broadcast FM image in the video below. On Pups blog there are also more posts about the board under this tag.