Lightening protection (or attraction?)

[4wd]

So, some quite active sky a few times a month here (F), have added my (lack of) concept of lightening protection to the roof dish. Am not on any mountain top so will probably be fine anyway, any opinions if this is purely psychological or may it have some real effect ...or will it make my dish a prime target :O) (see pictures). Wire approx 1 cm, ground spikes 2 x 1 cm 1,5 m long.

 

[RustySpoons]

I always remove all my coax when we have a storm, on the ham radio I ground all the antennas.

 

[Terryl]

I have gas discharge devices on all my radio and satellite equipment.

4WD, the cable you have attached to the mount is it aluminum or plated copper? If it is steel then it's not a safe Earth ground,(steel is a very poor electrical conductor) I use a #6 solid copper wire bonded to my main RF ground as I am in a lightning prone area, my main VHF/UHF ham antenna is the biggest and tallest item around,(95 feet AGL) it has a copper tip that is directly attached to the main RF Earth ground.(antenna designed that way)

And the rebar you used is not that good of a ground point, get a real ground rod (2 meters or longer) and a proper bonding clamp, as the rebar and clamps will rust and your ground go's by by..

In my area the Earth conductivity is very poor, so a standard electrical service ground does nothing for lighting protection, this is why I used a 6 point radial ground made out of 1/2 copper pipe, each horizontal radial is 100 feet long and bonded at the center point, (copper was cheap when I did this) this is my main RF ground and all my equipment is attached to this ground.

Now, on most satellite systems they only attach a ground block, this only grounds the shield of the coax, it does nothing to protect the center conductor, only a gas discharge device will do this, they may be a bit expensive but they help a lot better the a ground block.

I also use several UPS systems that have an RF signal pass through, the UPS equipment I use for this comes with attached equipment insurance, once your registered your protected, if lightning or any other type of power surge gets through the UPS you get new equipment.

Now..There are no safeguards that will protect you against equipment damage from a direct lightning hit except a total disconnection from the antenna(s) and AC service as RustySpoons mentioned, so on my realy expensive stuff I have RF isolation switches that connect the RF inputs directly to ground, there is also another problem with a close by lighting hit, and this is EMP**, it can wipe out equipment without even touching your antenna or AC service.

**EMP, ElectroMagnetic Pulse

A lighting hit that is large enough can create an EMP pulse big enough to wipe out anything with a transistor or IC chip, I have seen this happen many many times in my 65 years as a broadcast engineer, this is why I have a lot of protection.(and a lot of redundancy)

 

[4wd]

^^^ Thanks for the info. It's a steel cable. Will get the better components and improve it.

 

[archive10]

Maybe the trick is to find the local HAM enthusiast with the 95 ft high-conduicting antenna, and move in next door.
But then again, lightning strikes are by nature (or is that Nature?) unpredictable, so can strike anywhere...
Alternative is just to buy cheap stuff, and replace things if ever hit...

 

[Terryl]

In lightning prone areas (like Florida) we recommend the use of lightning rods, but they should be installed by a licensed contractor for insurance reasons.

 

[Terryl]

Us radio and TV broadcasters have some of the tallest things around built by man,(radio and TV towers) we use all sorts of things to try and keep the lightning away from some very expensive transmitters.

The best thing I have seen that works most of the time looks like one of those things used fro getting the cobwebs out of the corners of the ceiling, except ours are made out of stainless steel, although lightning goes where it wants to go, and not much will stop it.

You should be in the transmitter shack during a thunder storm, your hair will sometimes stand on end, that's when you sit in the nice rubber chair and keep your feet off the floor.