First I measured a small bench network using Simnet cable at home.
As was expected, this added a bit of capacitance to the cable: the rising flank of the pulses aren't straight up anymore, especially once the voltage reaches 2,5 V, and the ringing is back. I didn't expect that.
The noise filter also has as an added benefit that the network will work more reliably when the cable going up the mast to the wind sensor is removed, either because accidentally or on purpose.
ConclusionThe Simnet Noise Filter seems to work and improve the signal behavior of the two networks that I tested it on, and I intend to keep it installed. It is recommended for large(r) Simnet networks.
It would be interesting to see the effect of such a network on other brands of NMEA 2000 cable.