Lightning protection (Polyphasers and cadweld)

[N2RJ]

Let's talk lightning protection. Specifically polyphasers.

What do you guys think about them? I was told I should order one for each coax line (three in total).

I'm also going to get some ground rods at Home depot as well and see if I could get some copper flashing and cadweld shots (not from HD, but ordered online).

My friend Peter, W2IRT, is currently working on his grounding project, and has told me that I should use nothing less than exothermically welded connections and to MAKE SURE to use cadweld shots to weld them.

What grounding advice do ye fellow misfits have?

[ad4mg]

Let's talk lightning protection. Specifically polyphasers.

What do you guys think about them? I was told I should order one for each coax line (three in total).

I'm also going to get some ground rods at Home depot as well and see if I could get some copper flashing and cadweld shots (not from HD, but ordered online).

My friend Peter, W2IRT, is currently working on his grounding project, and has told me that I should use nothing less than exothermically welded connections and to MAKE SURE to use cadweld shots to weld them.

What grounding advice do ye fellow misfits have?

Ah, a topic I know a little about. Although I'm foolish for not doing so, I have yet to install polyphasers here. On our hospital system, we use them on every antenna, at every location. Good, sound mechanical connections (electrozinc plated) to bare building steel was utilized there. I think cadwell shots are a bit of overkill. What you want is a good, low impedance path to ground, and good, heavy mechanical connectors, properly installed, and protected from corrosion should suffice.

Until I get around to installing polyphasers, I rely on a decent ground system comprised of 4 each 8' ground rods, tied together with #0 welding cable (soldered connections), to a common bus behind my gear. I use the flat, braided straps to connect the equipment to the bus.

I'm ashamed to say that I still rely on unhooking the coax from each radio, and pulling the plugs out of the wall outlets as lightning protection.

Also, unless you are willing to spend thousands of dollars on lightning protection, you aren't going to "survive" a direct hit anyway. And ... most damage is caused by spikes in electrical wiring, plus the "umbrella effect" of lightning. Polyphasers, in conjunction with a good earth ground will provide protection against the indirect stuff, and maybe some smaller, direct hits. That leaves what to do about surges along the electrical wiring of your shack. Like I mentioned, I always unplug everything!

[N3ATS]

Good advice from MG, except you never want to rely on a soldered connection solely. Solder melts at 300 degrees and a hot strike could destroy your connection. Solder is fine, however a mechanical connection (crimp) should always be the primary means of connection. If you want to crimp AND solder, that's cool. That's how my indoor buss is setup.

Yeah I know, I zapped a few diodes in my tuner today, that's because I was too lazy to run the coax through my PolyPhaser buss outside. It was a temporary setup and I didn't expect the storm this morning.

Ryan, I assume you have a tower, so here is a quick down and dirty crash course in grounding. This is Motorola R56 spec, and I do this at work when consulting on sites, so I hope to give you the best advice I have.

Pound in three ground rods. Make sure they are twice the distance apart that they are long. In other words, if you have 8' rods, make sure they are 16' apart.

Connect all the ground rods together via an exothermic connection using 2/0 AWG minimum copper cable. If you can find the uninsulated, solid, tinned copper stuff, all the better. The construction of a ground ring or halo, is the best way to do this. Basically a loop around your tower.

Your radio station and tower ground should be tied into your electrical service ground as well. Remember, single point ground system.

Connect each leg of the tower (I am assuming three here) to the the ground ring using 2/0 AWG minimum copper cable. DO NOT drill into the tower legs. Either CAD weld them or use the existing bolts that hold the sections together.

Install a copper buss bar somewhere on the tower. Install ground kits on your coax shield and ground them to the tower buss. Connect the buss to the ground ring via 2/0 AWG minimum insulated copper cable.

Right where the cables make entry into the shack install another copper ground buss, and attach your PolyPhasers to it. Bolt them on using an anti-oxidant compound. PolyPhaser makes stuff that looks like copper gel, or you can use Noalox. Connect this buss to your halo ground using 2/0 minimum insulated copper cable. You can bolt it on or CAD weld the ground cable.

Inside, install a third buss. Connect your equipment to it using 8 AWG minimum insulated copper cable. Be sure to use a seperate cable for EACH piece of equipment. Do not daisy-chain equipment together. Connect the inside buss to the outside buss using 2/0 AWG minimum insulated copper cable.

Be sure to use a REAL AC surge protector on your equipment as well.

If you want, I can end you the Motorola R56 grounding spec. It's a HUGE .pdf file. Just let me know, and I will send it to your E-Mail!

PICS!!!!

http://i81.photobucket.com/albums/j238/swweiss/tower_ground.jpg


http://i81.photobucket.com/albums/j238/swweiss/Transmission_Line_Grounding.jpg


http://i81.photobucket.com/albums/j238/swweiss/Site_Grounding.jpg


http://i81.photobucket.com/albums/j238/swweiss/Shelter_Grounding_Internal.jpg

[N2RJ]

Thanks. This is exactly what I needed.

The tower is not up yet.

Just to give you an idea, the tower is a 70' self supporting AN Wireless tower 90' away from the house. That was the best location I could have gotten without clearing a whole bunch of trees and obeying setbacks. Cables are going underground.

The cables are three runs - one 1/2" LDF4 (MonstIR), two 7/8" LDF5 Andrew Heliax (M2 2M18xxx and a dualband 2m/440 vertical) . I also have a 16 conductor Steppir cable and a 6 conductor rotor cable (Prosistel PST 71D.)

SO I guess the next question is, what should I get? Array solutions sells ICE, and DX Engineering sells Polyphaser.

As for grounding the heliax at the base of the tower, what is recommended?

What about at the top?

[N3ATS]

You need ground kits specifically for Heliax.

http://www.tessco.com/products/displayP ... ventPage=1 (http://www.tessco.com/products/displayProductInfo.do?sku=439616&eventPage=1)

http://www.tessco.com/products/displayP ... ventPage=1 (http://www.tessco.com/products/displayProductInfo.do?sku=11149&eventPage=1)

You can ground the lines to a buss bar at the base of the tower or attach them to one of the tower bolts. Just remove any paint and use an anti-oxidant. Same thing at the top. A buss bar is recommended, though they are very expensive.

I have never used ICE. Always PolyPhaser, so I can't tell you which way to go on that.