Galvanic isolation revisited.

Interesting.

Ethernet is inherently galvanically isolated. The reason for this probably has to do with the long distances it is designed to cover. You can’t be transmitting a signal with different ground potential references very well, so there are isolation transformers on either end of every twisted pair in an Ethernet cable (PoE may be different).

What the EMO seem to do very well is add a LOT of protection against lightning/power surges breaking through, as well as low frequency (audio and power) attenuation.

I would totally want to put one of these between my cable modem and Wifi router at least to reduce the chance of lightning induced surges.

How much was it? And how did you purchase?

I bought it directly from Germany, somewhere around $80. Agree with you and originally had it before the switches. Had an Aha moment when sticking it right in front of the server. The system seemed suddenly 2-3 db louder and more resolving. Given the effect I think it was more likely some ground level noise than RFI but not sure

…and btw: while inherently galvanically isolated Ethernet benefits in a big way from the Etherregen‘s moat. Go figure.

Which EMO - like this, or this, also available here?

I use an EMO EN70HD