But how much of that is the towel and how much is the wet?
The towel [dry] had almost zero effect.
For the same reason microwave ovens work, it's the water content that's the issue.
It isn't so much "the leaf" is it as the water in it.
Without access to my old lab, last year I had use of an AIM and tried to see how one might improve rainfade.
A wet towel over the reflector was my starting point. Then I tried several partial covering of the reflector.
None turned out to work very well as the water simply attenuated too much until it started evaporating.
Somewhat stumped on how to progress, I found sheets of sandpaper covering the LNB gave me more control.
With 40 sheets [which was about 1" thick] the CNR dropped 3 dB.
The outcomes of this was there isn't anything to improve rainfade "after" the LNB.
RainX and the like, aren't going to do squat as the reflector simply doesn't retain that much water, "unless" it's wet snow.
I've seen photos of snow inches thick on the dish with reports of no signal problems, which can only be due to very dry snow.
Sierra snow is called Sierra cement for a good reason, as it's more water than snow.
If you have heavy storms between the SAT and your dish, the only thing you have any control over is the dish.
Peaking it for maximum gain, increasing the reflector size, cleaning off any snow, or increasing the gain of the LNB [someday I hope] is it.