FWIW, when we installed a Purewave basestation a couple years ago, they
recommended a Connectronics P/N 82-8694 protector for the 48V DC, which we
used at the top next to the basestation. While expensive, it's pretty nice,
even has a light to tell you power is on. And since it's a little outdoor
enclosure with glands, you could use it to transition from 2-wire power
cable to Cat5 with an RJ45 on the end. We just used 12 AWG electrical wire
up the tower since it was inside conduit. Then tray cable to the special DC
connector the Purewave gear required.
http://www.connectronics.com/dealer/SolutionGuides/PoEProducts.pdf
One thing, I think this P/N might be for -48V polarity only. Does SAF
use -48 or +48?
-----Original Message-----
From: Craig Baird
Sent: Tuesday, May 26, 2015 12:44 PM
To: af@afmug.com
Subject: [AFMUG] SAF POE/Fiber question
I've got a few SAF Integra links that we'll be doing shortly. We're
planning to run fiber to the radios. I'm wondering what's the best
method for powering the radios?
From what I gather, SAF has some sort of new kit where you can send
power up to the radio on 2-wire DC cable. At the top, near the radio,
there is a pigtail that takes power off the 2-wire cable, and puts it
on another cable with an RJ-45 for plugging into the ethernet port on
the radio.
I have a couple of issues with this method. First of all, it appears
they use a Bulgin outdoor coupler to make the transition from 2-wire
cable to CAT5 cable. I've found those Bulgin couplers to be less than
reliable over the long term with regard to water ingress. So that
makes me nervous. My second issue is lightning protection over the DC
cable. I'm sure there are products that are designed to protect DC
circuits. What would you guys recommend for protecting a DC circuit
running up the tower?
Overall, I'm wondering what would be wrong with just running shielded
CAT5e up to the radio for power purposes only? If we did that, we
could just use the WB surge protectors. Is there some advantage to
running 2-wire vs. CAT5 that I'm not seeing?
Craig
