Lightning Protection

Posted on June 25, 2013
Filed Under Amateur Radio | Leave a Comment

Last summer we took a direct lightning hit on my dipole antenna. The antenna was tied between two trees with the midpoint about 7 feet above the ground. Needless to say, we suffered major damage to appliances,computers,networking equipment and TV’s.

Oddly enough it did NOT hit my 50 foot tower located about 40 feet away. Nor did it hit the two story house next to the antenna.  The feedline came down from the dipole and I had wrapped it around the water spigot and then brought it around the house to the window where my shack “was” located on the ground floor.  Thankfully? Most of the discharge, I assumed arced to ground via the water pipe. The feedline between the spigot and antenna was essentially vaporized.

 

 

spigot

 

 

 

 

 

Of course the antenna itself was fried.

dipolecenterfeedline

 

 

 

 

 

Now I have added the following grounding to my house:

lightninghalo

 

 

 

 
Now the first question I have.. Assuming I have my feedline grounded at the top and bottom of the tower, and a polyphaser surge protector installed and grounded at the base of the tower, can I run the coax along the ground (or buried) around the house on the side away from the SVC ground, ground it again at the surface below the bulkhead which is located on the second floor, and run it up to the bulkhead.  The bulkhead is connected to the halo perimeter ground via copper flashing. The intent is to have a single common ground/entry to the shack. Where everything is connected, AC surge protector ground, Coaxial grounds etc. I suppose I could install another polyphaser on the feedline at the bulkhead too.

OR

Should I run it to the SVC GND side, make a bulkhead there for the cable,phone and Amateur gear, and then run it over to the shacks bulkhead?

I am somewhat worried about feedline loss but would rather be safe than sorry later. 🙂

I believe most of my damage last time actually came thru the feedline into the scanner it was plugged into. Thankfully it wasn’t connect at the time to my HF rig.  From there I assume it went everywhere via the AC power outlet.

Another minor question I have… On the right hand side of the house above is another water spigot, should I connect the perimeter ground to that spigot? Or would that possibly cause more problems?

Update:

I have received the two Alpha Delta TT3G50 coaxial surge protectors and the 16 50v MOV (for my rotor controller cable). Will be spending some time mounting the TT3G50’s at the base of my tower in an enclosure. And I will be routing the feedlines from there around to the shack. At which point another bulkhead will be placed. Would like to find a cheap source for some 1.5 or 2 inch copper strap/flashing.  After this is done it will pretty much complete my safeguards. I will be adding a couple more ground  ing radials at the base of my tower.  I will at some time,  ground the distant ends of the tower guy wires.  I need to move two of those that are anchored to trees and build their own anchors.

I remain concerned about a few items.
First, the tower is placed fairly close to the house and very close to our big TV in the living room. I am VERY concerned with any induced voltages (EMP) effects that a direct strike on the tower might provide.  Diverting as much energy as I can to the ground is a good start. But I can’t really put the TV in a Faraday cage. I guess endpoint surge protection devices are about all I can do. Of course the “correct” option would be to relocate the tower to a more distant location…

Secondly, we already have taken at least two hits to nearby trees that caused (EMP) or Ground Potential Rise damage. (surge).

My lack of endpoint surge devices allowed that to occur. (Now pretty much anything that comes into the house has some form of protection for surges).  I am considering some lightning protection for at least one of our trees.  Since these trees are much taller than our house or for that matter my tower, I feel it might be prudent to “protect” them so they hopefully can survive more hits.  One tree was killed. The latest strike did blow a stripe of bark off in a couple of places but the tree looks like it was not significantly damaged. Time will tell.

Third, I have lost much of my initial security camera system/DVR to the surges.  If I am going to replace them I will need to provide some form of protection on the camera video and power runs. Seems like whenever I lost a camera I also lost the video input on the DVR to which it was connected.

Last, I am considering a whole home AC protector at the main service panel. As far as I know to date we have not suffered any damage from INCOMING AC surges..but statistically most surge damages are caused by AC/Telco lines coming into the home.

I continue to be amazed that people think improving the grounding, installation of lightning protection systems will actually “attract” lightning.  If a stepped leader gets close enough to be “attracted” to my grounding system .. thats  GREAT!
Its going to hit anyway. At least this way I have some control on where the immense energy goes… I prefer it go to the Earth and not inside my home. I know that we will suffer some damage (likely) in the event of a direct hit.  But we can hopefully, minimize the damage to our home and electronics.

 

 

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