Lightning Strike at my QTH

[WA1GFZ]

NEC Bonded grounds helps lightning to reduce offset voltages between ground systems.

[N4LTA]

What are NEC Bonded Grounds?

The NEC requires that the grounded conductor (sometimes referred as the neutral) be bonded to the grounding conductor bus at the service entrance. It also requires that a grounding electrode be connected with a code sized grounding electrode conductor to the bonded point and that other specified "grounds" be bonded to the grounding electrode.

From that point downstream - the grounded conductor never touches the grounding conductor. No current flows in the grounding conductor (except in a fault) and so all points on the grounding conductor are at equal potential.

[VE1IDX]

Just my 2 cents here but something to think about in the case of towers with big antenna not getting hit while lower objects do is that the big antenna with multiple elements offer lots of pointed edges for static to bleed from much easier than from a single telephone pole or street light. The gentleman above that spoke of his tower with the log antenna is a classic example of the static being dissipated from the tower better and faster because of this than from the object that was hit.  I have read that in some cases even the millions of little tree branches and twigs may be able to bleed static off better than another nearby object depending on associated grounds etc. The "cone of protection" may well exist but it all depends on just how well surrounding object dissipate static compared to the object doing the protecting. During my stint in the broadcast biz I never had a lightning strike something nearby. I was always the unlucky SOB that protected everyone else in the area.

[w1vtp]

This map might be helpful in averting lightning problems

http://www.intellicast.com/Storm/Severe/Lightning.aspx

There are a lot good - useful maps.  Check out the "Storms" button and navigate.  Looks like we are OK for today in NE

Al

[WD5JKO]

I just come home from work, and there are nearly 30 responses to my original post! Thanks guys! I got a bunch of reading to do now. I am thinking about moving the antenna away from the house though...tentative, or just lower the tower (push up mast) when I'm gone for long periods (I travel a lot).

Jim
WD5JKO

[ka3zlr]

That Sounds very good the push up mast idea, moving the antenna away from the house is a sound idea for quite a number of reasons RFI EMI just general performance over all but listen close to what the guys tell ya theoretically an proven an make the best decisions ya can.

73

Jack.  ///

[K5UJ]

The thing you have to keep in mind about lightning, protection and counter measures is nothing currently (as far as I know) has a 100% guarantee of success.  The energy is so over the top you can't really exercise complete control over it so grounding, dissipation spikes, Xl loops, and all the rest have more to do with being insurance in the sense of trying to reduce exposure to damage or tip the odds somewhat.   So it is not that these things are pointless and should not be done--they should be--but that there's no such thing as being completely protected.

Push-up masts are okay for just holding up wires but they are a real pain to put up.  I'd go with the following:

10 foot long 6 inch x 6 inch pressure treated post 3 feet in the ground in concrete.  nylon strap wench at the top.  40 or 50 foot aluminum tube mast; maybe thin wall irrigation tubing on a hinge on the bottom of the post.  hook the wench to it and crank it up.    way way easier to raise and lower than a push up pole.   For aluminum you'd need a couple 24 foot sections, 3 or 4 inch o.d. and guy it half way up.  That's what I did.  works FB.  the post is an insulator so you can also use it as a vertical.   Talk to this guy http://www.penningerradio.com or a supplier of tubing in your area.   The longer each section the better.  short sections that can be shipped via UPS are too short and result in the whole thing being rickety.

[Opcom]

Glad it was not worse, hope everything is replaceable or repairable.
Yes, explain to the XYL the tower actually reduced the damage from that hit, maybe kept it from hitting the house directly.



Home owners ins. here covers that kind of thing at an extra cost but I hope it never happens. My tower is not grounded yet, it is only 30FT, not finished. Maybe I should see about the ground pretty quick.

[WD5JKO]

update;

   A few more discoveries. The living room TV setup with stereo, amp, Wii was pretty much unscathed except for the satellite box DVR. All were powered from a single power strip.

   My son had moved a Sony PS3 over there, and plugged it into another wall outlet. Turned out that the HDMI port on the PS3 was fried, but worse, the HDMI port on my HDTV is also fried. ;-(

so two items damaged had external connections, PS3 power to another outlet, and satellite TV settop box to roof mounted antenna.

The water sprinkler solenoid that opened up on zone 16 was the only one that had a metal pipe (copper). It pointed to my pool and would squirt over the sidewalk to raise the pool level. I bet a tentacle of lightning nailed that pipe as well.

It looks like there might be some common sense solutions to take when we wire up our computers, TV home entertainment centers, etc. Some clamp on ferrite beads can come in handy too. One idea is to use a single power strip (preferably containing a real surge suppression network), and clamp on some beads over the main power cord. Use that power for a single cluster of stuff.

Jim
WD5JKO

 

[WA1GFZ]

I would start with checking your local ground system.
Prayin won't help you and beads will do you no good

[N4LTA]

There is no absolute guarantee when it comes to lightning protection - But there are quite a few lightning protection system designers that will give a written guarantee -   if they install a system and they will pay for anything that is damaged.

I have engineered power systems with several of these companies , sometimes on facilities that have had repeated strikes and so far - I have never seen a claim against them - so you can do things that will stop 99% of the problems. Lightning does not have a mind of its on - it follows the rules of physics.

[K1JJ]

There is no absolute guarantee when it comes to lightning protection - But there are quite a few lightning protection system designers that will give a written guarantee -   if they install a system and they will pay for anything that is damaged.

I wonder if that means you could keep, say, an FT-1000D running with the receiver on and connected to a Yagi at the top of the tower when lightning struck the tower?

That may sound absurd, but when you think about it, many commercial repeators and cell phone type systems do just that.

When I hear the SO-239's in the shack snapping, I disconnect everything, even with good grounding thoughout. But I don't use any of those MOC and other related lightning suppression devices on the coax lines that absorb the energy. I'm sure this makes all the difference. Still, you would think that SOME energy still comes thru to the RX front end due to Ohms law and the division of paths - at least enuff to blow out an FET front end.

Big AL tells me he keeps his ants connected to the rigs during T-storms.

T

[WA1GFZ]

We make jet engine fuel controls and we don't shut down.

[w1vtp]

There is no absolute guarantee when it comes to lightning protection - But there are quite a few lightning protection system designers that will give a written guarantee -   if they install a system and they will pay for anything that is damaged.

I wonder if that means you could keep, say, an FT-1000D running with the receiver on and connected to a Yagi at the top of the tower when lightning struck the tower?

That may sound absurd, but when you think about it, many commercial repeators and cell phone type systems do just that.

When I hear the SO-239's in the shack snapping, I disconnect everything, even with good grounding thoughout. But I don't use any of those MOC and other related lightning suppression devices on the coax lines that absorb the energy. I'm sure this makes all the difference. Still, you would think that SOME energy still comes thru to the RX front end due to Ohms law and the division of paths - at least enuff to blow out an FET front end.

Big AL tells me he keeps his ants connected to the rigs during T-storms.

T

Decades ago I had a direct hit on my club's repeater (one that I cobbled up from a RCA 500 series FM transceiver).  It was a direct hit 'cause during the postmortem we discovered that there were pin holes on the hard line and at the time of the strike the lightning traveled down the control line and there were fireworks  - I mean fireworks in the room where the DC control panel was.

The strike blew the gas bags across the control line so there wasn't anything left but the wires going to them.

The repeater survived with no apparent damage!  Now - there were the duplexer cans, and a helicoil front end but the additional mystery was that the bipolar low noise preamp between the cans and the receiver front end was also undamaged.

Now dial in 30 years at another location and one more storm -- the poor gal gave up the ghost with one nearby strike.  No fireworks but something happened and she no longer would play.  My guess is that at the previous site a lot of attention was paid to the grounding system whereas the other site had no preparation whatsoever.  I wasn't the techie at the second installation

Al

[flintstone mop]

Glad it was not worse, hope everything is replaceable or repairable.
Yes, explain to the XYL the tower actually reduced the damage from that hit, maybe kept it from hitting the house directly.



Home owners ins. here covers that kind of thing at an extra cost but I hope it never happens. My tower is not grounded yet, it is only 30FT, not finished. Maybe I should see about the ground pretty quick.

YES for sure grounding. If it has a concrete base, it can get really ugly after a strike and not grounded.

It's true about most of the posts that it's no solid guaranteed insurance against a strike. And input from broadcast engineers is extremely valuable but we pow Ham folks cannot afford the extensive measures that b'casters do to protect their 24/7 operations. But we are good at copying and implementing as best we can. It's very hard for a Ham station to take a direct hit. A b'cast tower is usually huge and it and its ground system can absorb the massive energy.


Fred

[K5UJ]

<<<I wonder if that means you could keep, say, an FT-1000D running with the receiver on and connected to a Yagi at the top of the tower when lightning struck the tower?>>>

The problem with this picture is do you want to have to replace the 1000D?  Rigs I like that are no longer in production I tend to be very protective of   while I develop a contingency plan for the day when a needed part is unobtainium (Plan B: Johnson Ranger.  Unobtainum parts yes but not as many and potential substitutions).

In googling around for information on tower ball gaps I stumbled upon this interesting article:

http://www.radioworld.com/article/69646

[W3SLK]

I was told by a GE/Ericsonn rep, who became their lightning authority engineer, that regardless what you do to take steps to prevent damage, there is always the "Mother-of-all-lightning-strikes" lurking out there. However, the prevention schemes will prevent damage for about 90% of the strikes. One of the simplest, (and cheapest) prevention methods from power line strikes is to tie a series of over-hand knots (usually 3) in your power cord. I've seen where it had "stopped" at the first knot and left the equipment un-harmed.

[WD5JKO]

The list of discoveries continues:

1.) Replaced open sprinkler solenoid today, and it turned on immediately.  My Rainbird ESP-16i controller has one fried channel. Built in 1994, obsolete. Will tie zone 16 wire to another already used zone and see if that works. Most replacements available today that are affordable have a dozen or so zones maximum.

2.) The second garage door that we never open has a dead garage door opener

3.) The network printer that was out of toner got toner today. The static ip address cannot be pinged. Works with USB cable, but no nice TCP/IP connection now. The Ethernet switch was good. Looks like the Cat-5 input fried.

4.) Did find one CFL lamp out.

5.) Kids KLH 100W subwoofer fried. Ordered 100w ST-7294 power module


The good news though is that I did get on 75m a few days ago. The Windom antenna tunes "way-different" though.

Jim
WD5JKO