I see many E-foilers showing the RX (receiver) and the ESC (controller) either on top of each other, or super close.
From many years building RC planes and RC drones, I would try to separate as much as I can the receiver from any electronics, that includes the controller, the cables from the batteries, the cable running from the ESC to the motor, and the batteries.
A few specialists say that this is less true for modern 2.4GHZ frequencies, but since many of us will be tempted to use “marine” (therefore lower) frequencies, it may become an issue.
Ideally, the RX should have its own little box insert inside the board away from anything.
We don’t need range like RC, we only need a few meters range, rc needs up to kilometres of range which is why they need to be more mindful of receiver/antenna placement to limit losses in range due to electrical noise…I don’t think Efoilers need to worry about this to much.
As we are in a water environment + swimmers being at risk + several KW powers that necessarily generate interferences much stronger than the RC plane ones + a new born activity in a legal vacuum being scrutinized by the authorities, IMHO, multiple electromagnetic Interference (EMI) precautions are always better than one.
However, I don’t recall to have read the story of an efoil that went mad after the rider fall due to an EMI screening the reception of a power-kill signal.
Add remote control wet enclosure, beach guard radios, powerful harbor radios, board floating below the water surface, carbon fiber on board, full metal prop, DIY controllers, un-twisted power cables…
Just wait for our first “fly away” foil crashing into swimmers nearby (Murphy law).
Users here have to make sure they are at least using a safety measure (fail safe) before their first rodeo.