Lightning Strikes

[Chris_Milwaukee]

With thunderstorm season upon us, I am just curious about what happens when a stick takes a strike. What kind of protection does the transmitter have? Does the signal drop out after a strike? Does the antenna routinely suffer damage if it gets hit by lightning? Can a lightning strike fry out the transmitter?

I was bar-b-queing chicken when it started to storm out and with two towers literally in my front yard I just started thinking about one of those suckers getting hit...

Thanks again for your insight.

Chris from Milwaukee

 

[k9ez]

> With thunderstorm season upon us, I am just curious about
> what happens when a stick takes a strike. What kind of
> protection does the transmitter have? Does the signal drop
> out after a strike? Does the antenna routinely suffer
> damage if it gets hit by lightning? Can a lightning strike
> fry out the transmitter?
>
> I was bar-b-queing chicken when it started to storm out and
> with two towers literally in my front yard I just started
> thinking about one of those suckers getting hit...
>
> Thanks again for your insight.
>
> Chris from Milwaukee
>


The transmitter typically kick out for a brief ammount of time, then fire right back up (if things are operating properly).

Some of our sticks in Milwaukee have taken direct hits without too much damage. We get more damage from the power company than we do lightning. Having a good surge protector on site seems to help.

You shoudl see when lightning strike within about 3 miles at the nine tower WISN array. It is like a Frankenstein experiment! WO HOOOOOOO Duck and cover!!

 

[Chris_Milwaukee]

> > With thunderstorm season upon us, I am just curious about
> > what happens when a stick takes a strike. What kind of
> > protection does the transmitter have? Does the signal
> drop
> > out after a strike? Does the antenna routinely suffer
> > damage if it gets hit by lightning? Can a lightning
> strike
> > fry out the transmitter?
> >
> > I was bar-b-queing chicken when it started to storm out
> and
> > with two towers literally in my front yard I just started
> > thinking about one of those suckers getting hit...
> >
> > Thanks again for your insight.
> >
> > Chris from Milwaukee
> >
>
>
> The transmitter typically kick out for a brief ammount of
> time, then fire right back up (if things are operating
> properly).
>
> Some of our sticks in Milwaukee have taken direct hits
> without too much damage. We get more damage from the power
> company than we do lightning. Having a good surge protector
> on site seems to help.
>
> You shoudl see when lightning strike within about 3 miles at
> the nine tower WISN array. It is like a Frankenstein
> experiment! WO HOOOOOOO Duck and cover!!
>
Hey Kent... I live about 2 to 3 blocks from the channel 12 and 58 towers. If you're telling me that something "spectacular" happens when one of these babies takes a hit, should I be concerned?

 

[SamBuca]

> You shoudl see when lightning strike within about 3 miles at
> the nine tower WISN array. It is like a Frankenstein
> experiment! WO HOOOOOOO Duck and cover!!

I had my first lightning strike experience last fall. We took a direct hit to the tower and an indirect hit to the studio within 5 mins of each other. Too muddy to get my sedan to the site so I walked half a mile back there. Reset the VSWR trip, xmtr came back, but was still off the air. While rushing to lock the gate and run back to the car, something in the field got hit.

If you don't believe in a higher power, you will when you're that close to a strike.<P ID="signature">______________
</P>

 

[MrMissRadio]

> With thunderstorm season upon us, I am just curious about
> what happens when a stick takes a strike. What kind of
> protection does the transmitter have? Does the signal drop
> out after a strike? Does the antenna routinely suffer
> damage if it gets hit by lightning? Can a lightning strike
> fry out the transmitter?
>
> I was bar-b-queing chicken when it started to storm out and
> with two towers literally in my front yard I just started
> thinking about one of those suckers getting hit...
>
> Thanks again for your insight.
>
> Chris from Milwaukee
>

The biggest thing for a transmitter and tower is to be really, really well grounded. You can not have too much grounding. Did I mention you need to be grounded?

Lightning could indeed fry the transmitter, or the antenna, or the coax cable.

Some transmitters (and most newer ones) have something called VSWR foldback, which turns down the power output when reflected power (or lightning) comes calling. Reflected power often results from a mismatch between antenna and frequency.

Also, lightning can come in not only from the tower/antenna, but over the power lines, too.

If all goes well, it comes back solo. Next best you have to reset. I'd rather not talk about worst case.

I've always wanted to see a lightning strike on a tower, just not mine.

 

[rew]

> With thunderstorm season upon us, I am just curious about
> what happens when a stick takes a strike. What kind of
> protection does the transmitter have? Does the signal drop
> out after a strike? Does the antenna routinely suffer
> damage if it gets hit by lightning? Can a lightning strike
> fry out the transmitter?
>
> I was bar-b-queing chicken when it started to storm out and
> with two towers literally in my front yard I just started
> thinking about one of those suckers getting hit...
>
> Thanks again for your insight.
>
> Chris from Milwaukee
>


Lightning can do strange things. I have seen direct hits do major damage and no damage at all. You just never can tell what it will do. A good ground connection with everything connected to it can sure help. Surge suppressors also help but they are like birth control pills. You don't know when they work but you sure know it when they don't!

 

[k9ez]

> > > With thunderstorm season upon us, I am just curious
> about
> > > what happens when a stick takes a strike. What kind of
> > > protection does the transmitter have? Does the signal
> > drop
> > > out after a strike? Does the antenna routinely suffer
> > > damage if it gets hit by lightning? Can a lightning
> > strike
> > > fry out the transmitter?
> > >
> > > I was bar-b-queing chicken when it started to storm out
> > and
> > > with two towers literally in my front yard I just
> started
> > > thinking about one of those suckers getting hit...
> > >
> > > Thanks again for your insight.
> > >
> > > Chris from Milwaukee
> > >
> >
> >
> > The transmitter typically kick out for a brief ammount of
> > time, then fire right back up (if things are operating
> > properly).
> >
> > Some of our sticks in Milwaukee have taken direct hits
> > without too much damage. We get more damage from the
> power
> > company than we do lightning. Having a good surge
> protector
> > on site seems to help.
> >
> > You shoudl see when lightning strike within about 3 miles
> at
> > the nine tower WISN array. It is like a Frankenstein
> > experiment! WO HOOOOOOO Duck and cover!!
> >
> Hey Kent... I live about 2 to 3 blocks from the channel 12
> and 58 towers. If you're telling me that something
> "spectacular" happens when one of these babies takes a hit,
> should I be concerned?
>


I would not be concered about a pair of 1100' towers. When you have 9 tower bunched together, they tend to interact. Not only that but they shark together. You should hear the discharge run down the guy lines. It is more of a sound than anything else. I just would not want to be standing close to the guy lines when a storm is apporaching.

 

[TXengineer]

While our tower isn't the highest in the world (500 foot) , the top of the stick is just over 1000 feet above sea level so it is very attractive to lightning. Usually when lightning strikes the tower, all the monitors in the building become degaused, and the remote control serial line used to always get blown (I've since installed surge suppressors on the line at both ends, and am awaiting the next lightning storm). The actual transmitter doesn't usually do much of anything. One year back when the studios were co-located at the transmitter site, the roof of the building took a direct hit of lightning. (It's one of those roofs that have several communications antennas and a couple small towers on it). It was the worst damage the station had seen from a lightning strike. Several dumb terminals were blown, phone lines blown, a good $10k in damage to the NBC receive equipment, video control room frame syncs were all blown. It was quite the insurance adjustment! We had to basically "hop along" for about a week till some of the more critical things could be restarted. I remember after the hit, we had no phone service, and after I checked our transmitter room, I noticed the Generator transfer switch was in the Generator position, and when walking outside, all the fuses on the telephone poll were open. This of course was back in the day when the majority of people didn't have cell phones. We finally found one, however the cell tower at the site was apparently also down, so we had to go out on the tower catwalk to call out. I remember one of the FM stations also took a good sized hit, losing their remote control.
Afterwards, well the next day, I was having lunch at the Blimpie down the road, and the woman at the counter said to me "did you hear that lightning hit yesterday? it was so loud it shook our windows!". Yeah not only did I hear it...

The fun times, lightning is a dangerous animal.

<P ID="edit"><FONT class="small">Edited by TXengineer on 03/13/06 03:40 PM.</FONT></P>

 

[Robert Bass]

Not only that, it can also come in through phone lines. We had a blow out of an ARC-16 transmitter remote control unit, caused by a lightning strike’s surge on the phone line connected to it.

We’ve also had at least two antennas ruined by strikes, within a 10 year time frame. Whoever came up with the notion that lightning never strikes the same place twice, must have taken a strike directly on their head. It can and will and probably does happen more often than most of us realize.

There was also one instance of a strike to the tower that blew out some IC’s in the studio chassis portion of an Orban 8100 Optimod. The 8100 was located at the transmitter site just down the road, but the studio chassis unit was inside the studio. Somehow or another the surge from the lightning strike made it’s way into the Orban unit, and traveled back to the studio chassis unit.

There was also one time a lightning strike caused every single audio source channel on the station’s console to all come on at the same time, including the Mic. As a result, every audio source with fader start control came on. This would have included the three remaining music reel tape decks cued (the fourth deck was already on air), plus any of the 5 cart decks that happened to have been loaded. I didn’t hear what that sounded like, but I bet it was an interesting mix of programming.

Oh and let’s not forget the lightning strike on the clock tower that juiced up the flux capacitor, sending Marty McFly back to 1985.

R

> Also, lightning can come in not only from the tower/antenna,
> but over the power lines, too.

 

[SamBuca]

> Oh and let’s not forget the lightning strike on the clock
> tower that juiced up the flux capacitor, sending Marty McFly
> back to 1985.

I think it was his trip back to 1955 that caused the clock tower to get hit. People argue that they could have never calculated the precise second his hook made contact with the wire, and we certainly didn't see any capacitors on the line to hold the charge, so we must assume that the spike Doc put up there caused the leader to form. In turn, once the hook made contact, the flux capacitor provided the path to ground and the connection was made (the flux capacitor provides a true zero resistance path into the time continuum).

1.21 gigwatts is only 1,210 amps at a million volts. Not impressed. I look forward to the 1.21 gigawatt flux capacitor band pass device coming out on April 1st from Polyphaser.<P ID="signature">______________
</P>

 

[DXER1]

> > Oh and let’s not forget the lightning strike on the clock
> > tower that juiced up the flux capacitor, sending Marty
> McFly
> > back to 1985.
>
> I think it was his trip back to 1955 that caused the clock
> tower to get hit. People argue that they could have never
> calculated the precise second his hook made contact with the
> wire, and we certainly didn't see any capacitors on the line
> to hold the charge, so we must assume that the spike Doc put
> up there caused the leader to form. In turn, once the hook
> made contact, the flux capacitor provided the path to ground
> and the connection was made (the flux capacitor provides a
> true zero resistance path into the time continuum).
>
> 1.21 gigwatts is only 1,210 amps at a million volts. Not
> impressed. I look forward to the 1.21 gigawatt flux
> capacitor band pass device coming out on April 1st from
> Polyphaser.
>
Ya'll are both right I watched that movie lastnight. The movie was shot in 1985 but the time machine was set for November 5 1955. That is my favorite movie since I was born in the early 80s. <P ID="signature">______________
"I'm a gonna go to hell when I die!" Connan O'Brien

"yay boo, yay boo, it's lots of fun to do, if ya like it holler yay, and if ya don't ya holler boo!"

Connan O'Brien
</P>

 

[RockManAC]

> I just would not want to be standing
> close to the guy lines when a storm is apporaching.

I hate going out into the parking lot @ work during a t-storm since 1) the tower is about 20 feet from the parking lot and 2) the guy wires go right over it.

We apparently took a huge hit last night... I got in at 4:30 this morning to a host of things not working and reading over the notes from last night it sounded like our night MCO had some fun!

-A<P ID="signature">______________

</P>

 

[DXER1]

> > I just would not want to be standing
> > close to the guy lines when a storm is apporaching.
>
> I hate going out into the parking lot @ work during a
> t-storm since 1) the tower is about 20 feet from the parking
> lot and 2) the guy wires go right over it.
>
> We apparently took a huge hit last night... I got in at
> 4:30 this morning to a host of things not working and
> reading over the notes from last night it sounded like our
> night MCO had some fun!
>
> -A
>
I remember a few years back when I was down in Corpus and one of the Corpus TV towers got hit by lightning. My Aunt and Uncle's house are about 5 to 10 miles from most of the TV transmitters and you can see KIII-3 (ABC), KRIS-6 (NBC), KZTV- 10 (CBS) out in the open field, when I saw that strike I was like Holy Sh*t and got inside to check and see what channell it was and it ended up being KRIS's transmitter. I can see only the lights to KRIS's tower.<P ID="signature">______________
"I'm a gonna go to hell when I die!" Connan O'Brien

"yay boo, yay boo, it's lots of fun to do, if ya like it holler yay, and if ya don't ya holler boo!"

Connan O'Brien
</P>

 

[radioboy]

> With thunderstorm season upon us, I am just curious about
> what happens when a stick takes a strike. What kind of
> protection does the transmitter have? Does the signal drop
> out after a strike? Does the antenna routinely suffer
> damage if it gets hit by lightning? Can a lightning strike
> fry out the transmitter?
>
> I was bar-b-queing chicken when it started to storm out and
> with two towers literally in my front yard I just started
> thinking about one of those suckers getting hit...
>
> Thanks again for your insight.
>
> Chris from Milwaukee
>

Hi Chris,

I was on the air in 1984 when the station where I worked took a direct hit.
The station's studios, transmitter building and 231 foot tower were all together, with the tower just a few feet behind the studio building (an old mobile home.)

This station had been hit by lightning once before, during which time a Revox reel-to-reel machine mounted on the wall was knocked to the floor.

Well, the Florida T-storm rolled in and got closer and closer. Ten minutes into the storm, the tower took a direct hit. The record continued spinning on the turntable, with no sound. When the engineer came, he discovered that the beacon at the top of the tower was shattered; the transmitter tube was fried; the transmission line was burned; and several other things. We were off the air for two days waiting for parts.

Would you believe - two weeks later, same thing happened again!! The blast the second time blasted the surge protector box off the wall in the xmitter building, in addition to detroying many of the same components that had just been repaired.

They beefed up the surge protection substantially after that.

Being alone at the station in those storms was..frightening, to tell you the truth!<P ID="signature">______________
WJJD The Country Giant Revisited streams at
http://www.live365.com/stations/alanmccall</P>

 

[SML]

> I've always wanted to see a lightning strike on a tower,
> just not mine.

Here's a good one:

http://www.well.com/user/dmsml/portland.html

 

[Chris_Milwaukee]

> I remember a few years back when I was down in Corpus and
> one of the Corpus TV towers got hit by lightning. My Aunt
> and Uncle's house are about 5 to 10 miles from most of the
> TV transmitters and you can see KIII-3 (ABC), KRIS-6 (NBC),
> KZTV- 10 (CBS) out in the open field, when I saw that strike
> I was like Holy Sh*t and got inside to check and see what
> channell it was and it ended up being KRIS's transmitter. I
> can see only the lights to KRIS's tower.
>

When I was 13 I had a CB that I used to communicate with all my friends. Most of my friends had "kickers" and could get out pretty well. Since I didn't want "Uncle Charlie" visiting my house I decided to get some height on my antenna so I was allowed to put it up there, if you will. The house was already 30 feet tall, I modified a steel yard windmill tower that was 10 feet tall, added 30 feet of mast and the half wave antenna was 22 feet tall. Needless to say, that mother was up there. It was the tallest conductor in the neighborhood. The only concern my parents had was the thing might fall down and scrape up the cars in the driveway... they never thought about a lightning strike. However, I did.

To make sure that this would not be a problem, I fashioned a bracket that was connected to the radiator in my room. When a storm was forcast, I would disconnect the President Madison and attach the coax to the radiator. I figured that with my 6-guage ground wire outside and the RG-8U tied to a known grouond that I'd be OK... remember that I was 13 and everything that I had leaned about lightning protection came from some Radio Electronics (circa 1940) magazines I had inherited from my late uncle.

One night, I took a direct hit. Everything in the house glowed this incredible blue-ish color, it blew every fuse in the house, cooked the refridgerator and K.O.d the television that my father was watching. I cannot describe the deafening sound that came along with it.

In morning's light, I discovered that my antenna had vaporized (there was NOTHING left), the mast and tower were severly discolored, the coax was melted (just lucky the house didn't catch fire) and the insulation was gone on my 6-guage ground wire outside the house. Needless to say, my parents were pissed!

I still have the CB, it survived that night. I was only allowed to have a Starduster IN the attic after that.... and THAT took alot of negotiation!

Thanks to all the engineers for the stories. I appriciate all the hard work you guys do for us listeners! And I appriciate you answering all of my questions... you guys rock!

Chris from Milwaukee

 

[robgrayson]

My brother told me about a strike that WRBC in Jackson, MS took in the early 70's. It came as the jock was playing "Lightning's Girl" by Nancy Sinatra...
"Stay away from Lightning's girl, and this part of town;
Stay away from Lightning's girl, or he'll put you down.."
The strike came right on cue and "put them down".
RG

 

[mr_elbows]

> With thunderstorm season upon us, I am just curious about
> what happens when a stick takes a strike. What kind of
> protection does the transmitter have? Does the signal drop
> out after a strike? Does the antenna routinely suffer
> damage if it gets hit by lightning? Can a lightning strike
> fry out the transmitter?
>
> I was bar-b-queing chicken when it started to storm out and
> with two towers literally in my front yard I just started
> thinking about one of those suckers getting hit...
>
> Thanks again for your insight.
>
> Chris from Milwaukee
>

OK

as a veteran of more lightning damage than I care to recount (20 yrs in broadcasting + 15 in the 2-way business), here's my thoughts on it:

1) you can never prove you had enough grounding; only that you didn't

2) bond EVERYTHING together.....transmitter, racks, telco ground, power company ground with copper strap; ground those out as many sides of the building as possible to SEVERAL rods at each point

3) ground guy wires

4) it doesn't matter if, during a strike, that the equipment in the building is at 'X' potential above ground, as long as ALL of it is at the same potential

5) REA grounds suck, big time

6) ditto telco 'grounds'

7) if a new installation, overkill it in the plans, then double it at install time

8) pray a lot

E

 

[mr_elbows]

> > With thunderstorm season upon us, I am just curious about
> > what happens when a stick takes a strike. What kind of
> > protection does the transmitter have? Does the signal
> drop
> > out after a strike? Does the antenna routinely suffer
> > damage if it gets hit by lightning? Can a lightning
> strike
> > fry out the transmitter?
> >
> > I was bar-b-queing chicken when it started to storm out
> and
> > with two towers literally in my front yard I just started
> > thinking about one of those suckers getting hit...
> >
> > Thanks again for your insight.
> >
> > Chris from Milwaukee
> >
>
> The biggest thing for a transmitter and tower is to be
> really, really well grounded. You can not have too much
> grounding. Did I mention you need to be grounded?
>
> Lightning could indeed fry the transmitter, or the antenna,
> or the coax cable.
>
> Some transmitters (and most newer ones) have something
> called VSWR foldback, which turns down the power output when
> reflected power (or lightning) comes calling. Reflected
> power often results from a mismatch between antenna and
> frequency.

you can't be serious about the 'foldback' thing

there's no way it can react quickly enough


>
> Also, lightning can come in not only from the tower/antenna,
> but over the power lines, too.
>
> If all goes well, it comes back solo. Next best you have to
> reset. I'd rather not talk about worst case.
>
> I've always wanted to see a lightning strike on a tower,
> just not mine.
>

 

[ontheair247]

> > I remember a few years back when I was down in Corpus and
> > one of the Corpus TV towers got hit by lightning. My Aunt
> > and Uncle's house are about 5 to 10 miles from most of the
>
>> Chris from Milwaukee
>
It surely seems like everyone has a few good lightning stories.
I've seen AM directional towers take hit after hit and a second after, the transmitter would come back up and keep on ticking.

It was also a very picteresque site to be driving past the World Trade Center in NY one afternoon and see and hear that thing get hit in an electical storm.

The sight of an approaching storm will also tend to get you down off the radio tower when you're up for a climb rather quick.

One strike I remember is when I was the engineering supervisor at the Staten Island Teleport. It's a rather large installation with several dozen large domestic and international satellite antennas with RF and control buildings located thoughout a large infield.

One afternoon I was with a few techs working on something in "Shelter 6" as we called it. The afternoon sunlight suddenly darkened and turned into a dark violet glow, then a rather large lightning hit struck something somewhere. From inside the equipment shelter I saw a purple arc come dancing down the inside of the steel door towards ground.

As soon as the lightning cleared I found many of the motor contactors that steer the large satellite dishes had welded shut and caused the antennas to move off the birds until they came to a mechanical or electrical stop. After replacing enough gear to enable the dishes to track again, what followed was a heavy week or 2 of overtime repairing and replacing chips, transistors and relays mostly on the antenna controllers that track inclined orbit satellites.

Some of the other non critical things had gotten zapped such as the facility PA system, etc.

More recently at a studio STL tower the strobe light controls that light the top obstruction light and some computer KVM extenders inside a room where many of the lines come in got zapped.

When installing a ground system it is usual practice to keep the flow to ground directed in a downward manner for the system to be effective.

George Kowal CBNT