aerial Ethernet

geezer

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I've seen a handful of references on this board to running aerial cable. Though it's never the best choice, sometimes it may be the only choice, so I thought I'd make a comment or two about installation.

Using Ethernet cable with a built-in steel support strand is a must, and you can't just put it up like a clothesline. Both ends of each span need to be attached with strain relief.

This applies to a span of just a few meters from rooftop to pole as well as to pole-to-pole spans up to the maximum rated spec of 70 meters.

As a lineman back in pre-history for Ma Bell, the two-conductor drop wire we used was very tough and nearly flat. Self-tightening clamps were perfect for that cable, but they cannot be used on Ethernet wire which is round and not nearly so tough.

There are plastic roundabout clamps that are popular these days but they too are no good for Ethernet. Their S-curves are too small and thus violate the 2cm radius rule. A tight turn is exactly the wrong place to apply the weight of a long span.

There may be clamps especially designed for use with support-strand Ethernet cable but they're not available to me here in this "developing" country. So, what to do?

The answer is to make use of the support strand itself. If you are going from span to span, use something like a dull butter knife to carefully separate about 12 inches of the support wire from the rest of the cable. Bend the steel wire with pliers to form a loop that can be hung on the J-hook or whatever is on the pole. The Ethernet part of the cable will form a gentle loop that is well withing the comfort zone of the inner conductors.

For a span from pole to house, you might want to remove the support strand for the remaining distance from the entry point to it's termination at a POE NVR or POE switch.

One variation on this method is to do as described but then add the use S-curve strain relievers. Wrap the support strand securely around the curves and use the clamp's hook to hang the wire. This was my choice for the 38 meter span and 5 meter drop that I hung two years ago. It's done well in all kinds of tropical storms and that's a relief to me; hanging wire is hard and risky work, don't want to have to re-do it.Not good for Ethernet   Drop-Wire-Clamp 2.jpg Not good for Ethernet   Drop-Wire-Clamp 1.jpg outdoor cat5e with support strand.jpg
 

bababouy

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Any time we have had to run aerial cat5 cable, we would use a guide cable then lightly twist the cat5 around it. We used UV protected cable, but we weren't running it more than 30-40 ft. Thanks for the advice.
 

geezer

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I think using a guide cable is a fine idea for short to medium spans. Might be too heavy overall for a really long one. What sort of guide cable did you use?
 

TonyR

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I hung several thousand feet of galvanized 3/8" and 1/4" messenger my first 2 years of my career in GA, installing traffic signals using Klein grips, come-alongs, three bolt clamps and fan wraps. Glad I got that over with when I was 24!

An overhead span for Ethernet may be a perfect solution for some but here in AL, next door to the self-proclaimed "Lightning Capital of the World" state of FL, I advise against it. I have replaced many such spans of 50 to 100 feet that were affected by nearby lightning strikes that destroyed network equipment on both ends of the cable; the DSL modem was not affected, so it did not come in on the phone line. In place of the overhead cable I installed a Layer 2 transparent bridge using 2 each 5GHz Ubiquiti NSM5 Loco radios. Of course, it costs more and one must have Line of Sight but so far the 6 or so I've installed locally between houses and barns, shops an sheds have survived the merciless static of Alabama lightning over the last 5 years.

If budget does not permit AND the overhead span is to be installed in a lightning prone area at the very least I recommend STP and Ethernet/POE surge protectors. I would recommend at least one Ubiquiti ETH-SP installed and grounded at the entrance to the house. I use Ubiquiti ToughCable Pro, their shielded RJ-45 connectors and their ETH-SP surge protector.

As a condition of their warranty, Ubiquiti requires that outdoor runs be shielded and grounded and they furnish the image below. Note that my only issue with what they show in the image is the shielded cable going into the house....I do not do that on mine or those that I have installed. I X'ed it out on the image. I also drove a 4 ft. galvanized ground rod at both ends, used a ETH-SP at both ends within 1 foot of the rod and tied the grounding tab of the ETH-SP to the rod using a ground clamp with a short (12" to 18" max) piece of #10 copper wire.

MY primary concern is keeping ESD out of the house and off the LAN; protecting the CPE (IP cam, radio, etc.) is secondary, IMO.

Ubiquiti_ESD_Protection_no-STP-to-LAN.jpg
 

tangent

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call me old fashioned, but I've never seen lightning cross a fiber optic cable.
 

TonyR

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call me old fashioned, but I've never seen lightning cross a fiber optic cable.
Nope, me neither. It would be the ultimate media if budget permits. If a metallic messenger was involved, it would be the only thing susceptible to transporting ESD but it would be isolated from the components that one would be concerned about.
 
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