lutfulPremium
join:2005-06-16
Ottawa, ON Reviews:
 ·TekSavvy DSL
| stormchasing vehicles: your thoughts on lightning protection Imagine vehicle chases thunderstorms and photographs lightning at close range ... dozens of antennas sticking out through the roof ... people and equipment inside must be protected 100% from multiple direct strikes.
Please do not imagine the vehicle as an ungrounded but fully protected WISP enclosure ... for now.  |
|
 John GaltForward, MarchPremium
join:2004-09-30
Happy Camp
kudos:3 | Posting, like driving, shouldn't be done when you've been drinking.
--
The Truth is the foremost enemy of the State now.
|
|
1 edit | reply to lutful
Remote control the vehicle? No wait. That would add another antenna. That would be worse. |
|
| reply to lutful
Here's my shot at it... A bit of sarcasm with a side of possibly working...
Brass screening over all the windows to the body of the vehicle, to create a Faraday cage effect... Then attach a BIG ASS grounding strap from the rear of the vehicle dragging on the ground behind the vehicle... Lightning takes the least resisted path right??? Hmmmm
Have fun with that one guys... |
|
WHT
join:2010-03-26
kudos:3 | reply to lutful
Grounded shunt fed antennas or shunt lightning arrestor. |
|
|
|
1 edit | reply to lutful
said by lutful:Imagine vehicle chases thunderstorms and photographs lightning at close range ... dozens of antennas sticking out through the roof ... people and equipment inside must be protected 100% from multiple direct strikes. Please do not imagine the vehicle as an ungrounded but fully protected WISP enclosure ... for now. And thought this was a wisp forum...
My suggestion Lutful: step out of the car and take refuge under a tree: you will be safe there |
|
| Actually, and this is coming from a storm chaser... Under a tree in a lightning storm can be one of the WORST places you can be.. In a lightning storm you don't want to be near anything tall, wet, and or conductive... And believe it or not wood WILL conduct electricity just not very efficiently... Inside the vehicle is one of the safest places you can be...
Now tornado's, when it gets too hairy.. Ya basically just pull the vehicle over, get out, and lay as flat as possible... preferably not right next to the car and in a ditch if your in an area of the country that has those.. lol |
|
 Killa200Premium
join:2005-12-02
Southeast TN | said by toker815:Inside the vehicle is one of the safest places you can be... With today's modern vehicles that is debatable. Now if they were not 90% plastic and fiberglass.... |
|
| reply to snowpro2000
said by snowpro2000:said by lutful:Imagine vehicle chases thunderstorms and photographs lightning at close range ... dozens of antennas sticking out through the roof ... people and equipment inside must be protected 100% from multiple direct strikes. Please do not imagine the vehicle as an ungrounded but fully protected WISP enclosure ... for now. And thought this was a wisp forum... My suggestion Lutful: step out of the car and take refuge under a tree: you will be safe there What??!! That is absolutely the worst thing possible.
Trees are often the tallest object around, and if a tree gets struck, the current will jump to your body (because you are a better condutor of all that electricity than the tree is) seeking the best path to ground
Don't ever seek shelter under a tree in a thunderstorm.
Of course, if grapefruit-sized hail is falling, then it may be a matter of choosing between the lesser of two evils.
Death by blunt impact or electricution. Take your pick. |
|
| reply to Killa200
said by Killa200:said by toker815:Inside the vehicle is one of the safest places you can be... With today's modern vehicles that is debatable. Now if they were not 90% plastic and fiberglass.... Actually the body of the vehicle only plays a part of protecting the person or people in the vehicle.. It's actually the fact that the car is insulated from any actual ground from the 4 rubber tires... Similar to how the high power tension line workers with the helicopter can physically touch the lines and literally "become part of the circuit" with the electricity flowing directly through them.. It's because they have no contact to the ground what so ever...
As for my previous sarcastic comment with the grounding strap behind the vehicle... Please do not EVER ground your vehicle while in a lightning storm... IT WILL NOT PROTECT YOU.. In fact it will ATTRACT lightning.... Those rubber tires keeping you from completing a ground is 90% of your protection... I've also been a storm and tornado chaser for quite some time so I do have an idea of what I'm talking about.. |
|
 nunyaWho is John Galt?Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:5
 ·Charter
 ·voip.ms
| reply to lutful
Actually, the tires do not protect you. That's a myth. They are not rubber. They are synthetic. They DO conduct at high voltage (dirt and water on the surface). Remember things that act as an insulator at low KV can become conductors at extremely high voltages.
What protects you is the metal body of the vehicle. It "diverts" the lightning around the occupants.
»www.weatherimagery.com/blog/rubb···ghtning/
--
Looks like Reverend Wright got his wish - God Damn America.
Nancy Pelosi - House Minority Leader 2010
Harry Reid - Senate Minority Leader 2010 |
|
 Beebe
join:2002-10-25
Beebe, AR | reply to lutful
»www.youtube.com/watch?v=e4WAuGf6fsY |
|
1 edit | reply to lutful
Whilst Im sure snowpro2000 knows its not safe to stand under a tree during a lightning storm...
»www.thespec.com/article/816199
This happened to a guy running towards a tree in my local area when this seasons most intense lightning storm rolled thru on July 28th as a result of typical daytime heating in Southern Ontario.
I myself saw several direct strikes to this tower in a few minutes period whilst driving by (you can see this thing from anywhere), as well as several strikes that hit on the ground.
Ive also been a phone guy half my life and have seen lightning leave a telephone drop wire to a nearby tree with more than 12 inches of gap. Sometimes I think lightning doesn't take the path of least resistance, it simply takes the shortest path instead 
I also lost several CPE that day.
--
OptionsDSL Wireless Internet
»www.optionsdsl.ca |
|
Beebe
join:2002-10-25
Beebe, AR | reply to lutful
Lutful,
Are you saying that bonding is more important than grounding? The goal should be to keep the tower, cabinets, cable shield etc. at the same potential by bonding it together at a single point, and isolate the delicate equipment such as the radio board and the cat5 pairs from where the main strike will be?
Kind of like a person in a car. The car is not grounded, but the person is protected, as in the video above. He is like the radio board. He is told not to touch anything metal.
Thanks,
Roger |
|
| reply to nunya
said by nunya:Actually, the tires do not protect you. That's a myth. It is indeed a myth. Remember, that voltage just fell through a mile or two of open air. That last 14 inches of space between the bottom of yer car and the earth don't mean shit, rubber tires or not. If it wants to eat yer car, yer ass is grass and it will smoke you accordingly. |
|
WHT
join:2010-03-26
kudos:3 | reply to lutful
Many years ago, just before you drove up to a toll booth, there was a single wire sticking up out of the roadway that would make contact with the car chassis and discharge any static build up. I haven't seen those wires in years - I'll guess the rubber tires are more conductive now with the additives. |
|
lutfulPremium
join:2005-06-16
Ottawa, ON Reviews:
·TekSavvy DSL
| reply to John Galt
said by John Galt:Posting, like driving, shouldn't be done when you've been drinking. Because it makes seemingly smart people post such off-topic remarks. 
Since you had asked about "primary objective" in another thread, I wanted to have a lively discussion about protecting outdoor WISP installations without "grounding" as the term is currently understood in our forum. |
|
lutfulPremium
join:2005-06-16
Ottawa, ON Reviews:
·TekSavvy DSL
1 edit | reply to lutful
I checked the rest of the posts and noticed good points have been made by many including nunya, WHT, Beebe, Full Power and toker815.
Let us ignore the humans to make the problem quite similar to an outdoor WISP enclosure. The solution of course will be to create a Faraday cage but how would you prevent equipment damage from the surge energy entering through the (antenna) ports?
*** made a quick sketch of similar problems which have been "solved" by engineers without "grounding" ...
|
|
public
join:2002-01-19
Santa Clara, CA | reply to snowpro2000
said by snowpro2000:My suggestion Lutful: step out of the car and take refuge under a tree: you will be safe there Actually a car is relatively safe for occupants with no connections to the exterior. Lightning usually attaches to the roof, and flows through the frame to ground, causing one or more flat tires.
Radios are usually destroyed. With adequate feed through protectors, damage can be reduced. |
|
| reply to lutful
Many are missing a major and necessary point. Lightning is not a voltage source. It is a current source. Current will flow through the car body and create virtually no voltage inside. Tires that might stop that current means the voltage (body to street) increases as necessary to blow through (or around) those tires. That current will flow no matter what. You can determine whether it flows dissipating high energy (current through conductive wood) or low energy (current through the car body).
Why is a tree dangerous? Again, it is all about where the current flows. Lightning strikes a tree to connect to earthborne charges many miles away. A shortest path to charges five miles distant is three miles down to the tree. And four miles through earth to those earthborne charges. If you are standing below, a shortest path is up one leg and down the other. Your body is a shorter connection electrically.
Recommended - keep feet together. Then current incoming on one leg has nowhere to go on the other leg. Without both an incoming and outgoing path, then no surge damage - electrocution.
When discussing lightning, one does not discuss voltage. Current is the independent parameter. Voltage is only a resulting symptom. What is the current path – incoming and outgoing? If a lightning current exists, then both an incoming and outgoing path always exists. Voltage increases as necessary for that path to exist. How conductive is that path? A massive current on a conductive (low voltage) path means no energy – no harm.
That is also the concept behind a Faraday cage. |
|
