Not to go too far off track here, but what DC surge protectors have you used? I priced ones from Calix and they were sort of pricey (>100 each).
Josh On Tue, Dec 1, 2015 at 4:29 PM, Ken Hohhof <af...@kwisp.com> wrote: > I can't speak to R56, but the only experience I have with 48V direct DC > power is with a WiMAX basestation that the manufacturer claimed the field > failures were reduced to almost zero when they started recommending a DC > surge protector at the basestation. My personal view is the one by the BS > or AP (and it should be right next to it) is more important than one on the > ground. In our case, if a surge tried to blow out our rectifiers and > battery, it would probably just pop a fuse. Even so, replacing some 48V DC > equipment on the ground is no big deal compared to replacing an expensive > basestation up on a tower. > > > -----Original Message----- From: Craig Baird > Sent: Tuesday, December 01, 2015 3:11 PM > To: af@afmug.com > Subject: [AFMUG] POE vs DC and surge supression > > > We've got some Cambium PTP820S radios going up shortly. We will be > running fiber to the radios, so we're debating on POE vs. DC up the > tower for powering them. We have been told by the tower owner that we > need to adhere to R56 for lightning protection. > > Our initial thought was that we would just run POE since we already > have the cable, and it would give us an out-of-band management port. > But, according to the Cambium installation manual (and I think R56 > specifies this too), it says that if we're running POE, we're supposed > to bond the cable shield to the tower every 50 meters. I assume that > means at the top and bottom since our cable runs are all less than 50 > meters. In addition, the manual says that we should use Ethernet surge > suppressors. We're thinking "what a pain in the butt". On the other > hand, the Cambium manual does not address grounding for DC cable in > any way other than saying that the radio has DC (and Ethernet) surge > protection built in. > > So the DC option is looking pretty attractive compared to the hoops > we'll need jump through for ethernet. I'm wondering if there's > something we're missing that the Cambium manual doesn't address. I > figured just to be safe, we would go ahead and put DC surge > suppressors at the top and bottom of the DC cable. Is there anything > else needed for R56 adherence in this situation? > > Craig > > > >
