Back in 2018, we covered [Igor’s] Easy-SDR project that aimed to provide open hardware extensions for the chap RTL-SDR receivers. If you haven’t been there for a while, it’s worth a look as there have been many recent updates. According to the author’s Reddit post:

1. Most of the devices are now prepared for installation in a metal case measuring 80 x 50 x 20 millimeters.
2. There’s a completely redesigned LNA design. Now, Bias Tee powered amplifiers are housed in a 50 x 25 x 25mm metal case and have N-type connectors.
3. There’s an added amplifier based on the PGA-103 microcircuit.
4. Added is the ability to install filters in final amplifiers (a separate printed circuit board, depending on the filter used).
5. A new device – SPDT antenna switch for receiving antennas.
6. The upconverter has been redesigned. Added intermediate buffer stage between the crystal generator and mixer.
7. RF lines in all devices were recalculated to correspond to the characteristic wave impedance of 50 Ohm.
8. Reduced size of PI attenuator PCB.

There is an emphasis on ease of assembly, so the projects generally have a gerber file and can use through hole or surface mount parts. They are also available live on EasyEDA if you want to make changes. Some of the designs, like the new upconverter, are SMD only, but for some devices these days that’s your only choice.

We were impressed with the instructions included with some of the projects. It should be very possible to duplicate these projects with just a little effort. If you missed our first pass at [Igor’s] great repo, you can still catch up. Since he uses EasyEDA, you might want to read our experience with that, too.