Consensus around here seems to be that the Meanwell RSD series is a good option, and I have used a few of them for converting +-48vdc to 24v and 12v. Most recently I stuffed an RSD-100C-12 into a CRS354-48G-4S+2Q+RM. You could use the same, or an RSD-60L-12 would be a bit smaller and should still do the trick.
I've actually moved away from -48v positive ground power though, and I just use +48v negative ground power systems now. I have yet to run into a radio that actually needs -48vdc. Almost all of them will say -48v in the spec sheet, but when you check continuity between the power input and the chassis/ground, you find the power input is isolated, and every time I've contacted a radio manufacturer about it they have all confirmed that +48v power is fine. I think -48v power is more of a copper outside plant thing where you have to worry about galvanic corrosion. Someone as WISPA mentioned that -48v gets you some extra lightning protection since something like 95% of lightning strikes are energizing the tower with a strong negative charge, and like repels like, but then again the other 5% of strikes that are positive ground to cloud lightning are something like 100x more powerful, so I'm not sure I buy the -48v lightning protection argument. On Sat, Nov 5, 2022 at 2:56 PM Sterling Jacobson <sterl...@avative.net> wrote: > > > I’m not familiar with -48v power plant. > > > > What would it take to “convert” from a -48v wire pair to a 12v 1A wire > pair? > > > > I’m converting a Mikrotik CCR 2004 to -48v plant in my cabinets. > > The 2004 doesn’t have replaceable power supplies so I was just going to > cut and wire the 12v headers on the motherboard to a DC barrel installed on > the back of the unit alongside the AC Input… > > Not sure if that would be best, easiest? It’s easy to find 48v to 12v > downconverters, but -48v is a mystery to me. > > > > Help me demystify it? > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com >
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