[danner]

@danner: you may like this:

Even "discarding" the readings below a certain threshold, we also can make that they "appear" that are starting at 1 W/m2.
We never know the source code of "commercial products", but I will not be surprised if "solutions", like the one presented below, would be frequently used, to avoid a more complex (expensive) hardware design.
Of course, this "solution" will introduce a minimal error to all readings.

Code:

#if (Solar_Sensor == 2)      // Apogee SP-110: Self-Powered Pyranometer (Solar / UV interface R2= 4700 Ohm)  if (RX_Data[2] < 4) RX_Data[2] = 0;          SolarRad = map(RX_Data[2], 4, 1023, 0, 1750); #endif

So that clips anything below 4, and the next line maps 4 to be the beginning of reading, or 1?

One thing is sure: The cost of the Solar/UV interface does not reward the time and efforts that I have to spend to supporting it. So, once the board will be out of stock, it will not be publicly available again.

Sorry to have caused that. I should have swapped out the TX board earlier in the troubleshooting process, but because the wind/rain "worked", and me not being familiar enough with it, I assumed the TX board was ok.