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
- [AFMUG] POE vs DC and surge supression Craig Baird
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