[RFI] Server switching power supplies

[Martin Kratoska]

I have a question: I've come into some server switching power supplies 
which I want to use for transceivers powering. These PS are very 
powerful (80 - 200 Amps) and efficient but the main problem is the 
RFI/EMI. There are no schematics, the documents are kept secret, a 
schematic is an unobtainium (can anybody help?). Thus, it is difficult 
to design additional EMI options, also to put these PS into life is a 
bit tricky. Known working types/models are DPS-800GB A which is the same 
as ATSN-7001044-Y000 or HSTNS-PD05, manufactured by HP, Delta and 
Fujitsu and good up to 83 Amps and also D1570P-S1, sometimes known as 
DPS1570 used in Dell Poweredge R900, Dell Poweredge 6950 and Intel 
Server S7000FC4UR which are good up to 120 Amps.

Which RFI/EMI options should be added? There are some reports about 
issues every 70-100 kHz, from LF up to 10 MHz or slightly more. Anyway I 
am pretty sure that these server PS must be better than usual PC PS 
which we all use without any problem. It will be very nice to share some 
experience, documents and ideas. HW?

73,
Martin, OK1RR