I left my DreamCatcher outside during a rain shower. It’s not worked since. I suspect that it shorted out.
With that aside, a VNA is usually used to analyze passive components with two ports, or an active component whose net gain is zero (because some attenuators were inserted). Be VERY CAREFUL in hooking up a VNA to an active circuit because VNAs ports are very sensitive to a DC bias on the input and too much power. The commercial ones are very expensive. their annual calibration is expensive, and their repairs are astronomically expensive.
I have not used my signal generator and scope to my dreamcatcher because I don’t have a schematic. I have back-burnered the project because I don’t know the outcome of the big announcement today.
But assuming I wanted to fix it, there are several steps that I would take.
- Is the power supply working?
- Do the chips all have the needed power supply voltages?
- Does the CPU look like it’s working? There’s a heart beat LED that tells you if its running.
- Verify that it’s running the right software.
- With a small signal, follow the receive chain from the SMA LNA_BYPASS antenna connector past the mixer and the A/D sampler. The rest is software. The ARMbian load can run several programs that could help you debug the hardware, but this too is a rather closed system.
- If this works, debug the SMA_LNA input and see if the LNA and SAW filter are working. The LNA is extremely static sensitive. It’s easy to destroy with an accidental ESD discharge.
Depending on what today’s announcement is, my DreamCatcher may become a wall decoration and replaced, or something I will want to repair.