cars , airplanes and base antennas

[BOOTY MONSTER]

cars and trucks are insulated from earth ground by rubber tires . planes are isolated from earth ground because of the distance above it . when they are struck by lightning typically nothing happens . they also seem to get struck far less often than buildings and trees and such . why doesn't that same thing happen to a antenna/mast if its physically isolated from earth and earth ground and the coax is disconnected from the amp/radio inside that is grounded through the homes electrical system ?

 

[Robb]

Planes aren't a ground; they just become part of the path the goes to the ground.
Or so I was told, anyway . . .

Cars and trucks can a do get struck by lightning. Usually gives a vehicle flat tires immediately or leaks over a period of time.
Blows out the electrical system too. Lotsa other damage as well.

In each lightning strike to the earth, there is a leader charge that comes up out of the ground and meets the opposing charge coming down from the cloud side. It all happens so fast that it is hardly detectable to the eye. You can find pics on the internet of step leaders coming UP from broadcast towers and discharging upwards. Just look; you will find pics . . .

If an antenna is a poor conductor compared to the amperage a bolt carries, it will heat up and possible cause a fire. By ensuring a solid ground, there is less chance of massive heating and possible fire. That is why you want to ground it well.

 

[mackmobile43]

this is lightning glass dug from the earth.

 

[Robb]

Yep; that is a 'fulgarite'.

Fulgurite - Wikipedia, the free encyclopedia

 

[W5LZ]

Don't think of it as "ground", but as opposite charges. Those opposite charges tend to seek each other. For instance, lightning between two clouds. Planes can also hold a charge after landing. If you watch the fueling trucks, they run a ground strap from the truck to the plane before refueling it. (They're supposed to do the same thing at filling stations too, the tank fill caps before removing them.)
Just a matter of equalizing charges. Lightning is just a big charge and has either polarity at times.
- 'Doc