Hi All,
Looks like not many places left on the Net to discuss the DIY ham radio stuff. Glad I've found this one.
My current interests are in the area of multiband FT8 and WSPR monitoring, so I was looking for a low cost low noise receiver design.
I have a couple of RTL-SDR dongles running on 10m and 6m. Tried using these with an upconverter on lower bands, but the number of decodes was lower than with FT-817 (this is my "reference" receiver). This is not a low noise solution.
I also have some SoftRock receivers of different flavors. These are good for my use, the only drawback is that they require a stereo soundcard input and SDR software, raising a cost per band a bit.
So I wanted to try crystal filter based or phasing receivers to get rid of the unused sideband noise/interference.
Kits and Parts Universal receiver was the next thing I tried. I have a bunch of parts already, so I ordered a 1Watter bare PCB. Used Si5351A as the LO.
The receiver works well, my only issue with it is the filter bandwidth. FT8 requires full 3kHz. I also think that NE602 based frontend is probably not the lowest noise solution, but good enough on low bands.
Next thing was rolling my own. The design (schematic and PCB layout) can be seen here:
Please look at it and criticize. The boards can be ordered on EasyEDA/JLCPCB for cheap.
It uses ideas I got from different places. Many thanks to W7ZOI, N7ZWY, VE7BPO, W8DIZ and others.
73, Mike AF7KR
