@SteveH posted:Adrain, thank you for confirming this.
Assuming strategic location of TVS diodes elsewhere around a non-DCS layout (transformer outputs, and across accessories with coils and other locomotives on the tracks:
Would there be any significant attenuation of the TMCC signal by adding TVS diodes on a locomotive's motor driver board output(s) as well as on the PCB track power inputs, thereby maximizing protection of the electronics in the locomotives?
The short answer is no. The entire layout (trains, track, accessories, your body if you stand too close) are all one side of the legacy voltage ... the entire layout goes up and down at 455 KHz. The building ground (3rd prog of plugs, water pipes, ...) is the other side of the voltage. As long as the TVS is placed from layout thing to other layout thing, then it's capacitance is not presented to the legacy signal as a load it needs to drive.
Related side-note: Legacy/TMCC and the way it couples to antennas and the building ground is all super complicated equations because trains and layouts are usually "electrically short " - meaning it's not like traditional radiating 1/4 and 1/2 wave RF antennas, but like a dirty mix of capacitive couping and radiative coupling.
