Lighting arrestor for 1310 (integrated antenna)

xianglingzj · ‎08-29-2007

As I found that there is only one kind of lighting arrestor for 1310 bridge: AIR-ACC245LA-R, which is using PR-TNC connectors. May someone tell me that how can this be installed on a 1310 with an integrated antenna (i.e. AIR-BR1310G-x-K9)? Or it requires something else? thanks!

scottmac · ‎08-31-2007

In this case, the "lightning arrestor" (a really bad description of what it does) will go into the downlead (between the unit and the inside where you have stuff you want to protect).

Polyphaser (http://www.polyphaser.com ) makes a number of excellent products to protect coax and UTP downleads.

Personally, I would suggest, if at all possible, to use a segment of fiber optic cabling between the external unit and the inside stuff.

There are a variety of fiber/coppr transceivers available to do this, and IMO, worth every penny.

In every case I've seen (~a dozen or so) of lightning getting inside the wiring closet and/or ultimately, the data center, it's a total loss of the network equipment (and if the PBX is in the same room, the PBX and most / all of the phones too).

Inhsurance may or may not cover the entire loss financially, but the downtime and restorral time, and hassle of getting the replacement stuff ... the extra money to keep the lightning out is well worth it.

Also note that most "lightning arrestor" apparatus does wear out and requires periodic examination and replacement.

Good Luck

Scott

srosenthal · ‎09-05-2007

Scott,

If you connect the ground to the 1310 outdoor unit, then do you also need to connect the ground to the coax ground block before if connects to the power injector?

I know the manual shows both being grounded, but wondered if it is just redundent. The manual also shows the coax ground block being outside, so does this still apply if the ground block is inside?

Thanx,

Seth

scottmac · ‎09-05-2007

I believe it is best practice to ground the unit, and also ground the coax.

For a typical antenna installation, you'd ground the mast and ground (at least) the shield before entering the premises.

The (so-called and poorly named) "lightning arrestor" would also be grounded (that's the gas popper to the center conductor)outside of the premises.

With the goal of "keeping the damaging lightning outside" ... using a ground located inside the building seems, pardon me, like a Very Bad Idea.

In addition, I'd also like to point out that the quality of the ground connections is very important.

You need, at the minimum, a large guage (no less than 6ga), copper conductor. The path that the grounding wire takes should be as straight as possible (absolutely no 90 degree bends) and the connection to the grounding rod (or facilities ground) must be of the highest quality.

What happens if it's not straight or has a poor connection? Simple; it won't work! You'll have spent all the time & materials for something that still doesn't protect anyone or anything. To top it off, if it doesn't meet code requirements, the insurance company isn't obligated to pay for any of the damages, including death, injury, fire, or replacement of the damaged goods.

Also keep in mind that "lightning is not a manufacturing defect" .... you cannot RMA lightning damaged equipment.

External antenna systems and the "envitronmental protection" necessary to keep from frying all your equipment (and users)in a storm can be very complicated, and, as usual, varies greatly from one scenario to another.

PolyPhaser (www.polyphaser.com) has / used to have an exceptional book (cheap too!) on lightning protection systems. They are one of the industry leaders in protection systems. I think http://www.aesham.com also sells their stuff (amateur radio supply places in general).

So, short answer: Yes, ground at (at least) both places, unit and coax. In addition, you may want to ground in additional places (but be careful of loops), you should keep environmental grounding outside, and it should be a "good ground" ...

If you aren't certain about anything mentioned above, seek the assistance of a local professional i.e., one that has

1. ) antenna experience,

2. ) knowledge of the {Federal, State, and Local} electrical code,

3. ) grounding systems (EIA/TIA 568 and RF)

Good Luck

Scott