[RFI] 48v DC Clean Power Supply

[Jim Brown]

On 3/25/2020 11:40 AM, Jim McCook wrote:
> Jim, thanks for the ideas.  I'll look through that NCJ article again. 
> Addressing a possible common mode problem is a good idea.  That makes 
> perfect sense.  Paul at ARRL thought so, too.  My real challenge will be 
> getting this particular neighbor to cooperate, since he's basically 
> hostile.  Paul also had a suggestion which was to look at EMI filters 
> for this purpose at DX Engineering:
> 
> https://www.dxengineering.com/parts/dxe-iso-plus-10

Hi Jim,

I suspect that these boxes contain something approximating my 
recommendations, but who knows for what frequency range. Their virtue 
for you is that they are a simple "plug and play" approach that may be 
least likely to cause problems with your neighbor.

> --which could be a solution, except for a the POE cable that powers a 
> second similar switch in his office.  I have no real concern for 10 or 
> 15m now, but this is a new, rebuilt house, so I want to nip this in the 
> bud.  The longer I ignore the problem the harder it will be to deal with 
> this guy.

An important point that RFI guru Henry Ott made to me many years ago is 
that both ends of a data circuit are potential RFI sources, so chokes 
are likely required at both ends of each cable. Also, I've seen very 
nasty RFI produced by POE.

73, Jim K9YC