[werk_ag]

So, I guess that by decreasing resistance (using an R8 component with 10 instead of a "15 to 20 KOhm, 3362P-1-203 Variable Resistor") we should get a "stronger" signal.

Not exactly. Theoretically R8 can be a 10K fixed resistor, but even with an 1% precision resistor their value can be between 9.9K and 10.1K, and the most important: the Vref for the Arduino ADC is not always exactly 5V, so doing R8 variable, allow us to do some fine adjust. The procedure described on my previous topic, really helps to get a better precision from this instrument.
To better understand what I mean please refer to the document in this topic:

http://www.meteocercal.info/forum/Thread...nstruments

I think that the type of resistor that fits in the board does not exist with a value of 15K, so use a 20K, and to start adjust it as close as you can to 10K.