What is the EMR Range of Lightening?

It could be more than a hundred miles away, particularly at night. AIUI, there are receivers that can estimate the distance, based on the spectrum. We have such in "early-warning" systems to tell the line to "safe" the ugly processes. Announcements are made over the PA system to go into safe mode and to return to normal operation.

What the hell is an English major doing on the EE board?

Ah- but the difference between lightning and lightening (as per dumping ballast from a balloon or blowing tanks on a submarine) can affect the way that you shuffle off this mortal coil. More seriously- the distance that lightning Rf can propagate can be hundreds of miles. in many regions lightning detectors are used- but these are set up in stations so that it is possible to triangulate to determine the positoin of the stroke (and it is also possible to get a good estimate of the intensity).

"Lightning"

Does anyone know what the stations use for a clock when doing the triangulation? Or is it a matter of signal strength at each station when the strike happens?

I don't have a clue how it works. It seems to me that the different stations would have to have some kind of time reference.

A transmitter from a remote station would work. Even a phone line between the two would work. Subtract ping/2, or some such.

I think it can be done with one receiver though. ISTR the HF propagates faster than the LF from the stroke. This time difference can be used to estimate range.

I believe it is a matter of signal strength to estimate magnitude but determination of location is probably not affected by small differences in time of signal received (or this can be corrected easily- a series of blips matching another series which is a millisecond out of synch is not a problem). In any case it works quite well. The system I saw was used by the Alberta Forestry Department but I beileve that utilities in Montana also have a similar set up- possibly some info on IEEE or other sources (There is(or was) a NW US and Canada Group of utilities which have an annual conference to swap problems and solutions)

Do a google search on "Stormscope." No need for triangulation.

Al

13 years ago, or so, the 'stormscope' gave a real time picture of the strikes ahead of the plane. they were big bucks for a peon like me, so i didn't have one. i have seen them in action, tho. the name Robinson comes to mind,, or was it roberts? AFAIR the wave front had something to do with defining the stroke. i don't remember multiple antennas, tho. sammmm

OK. "How do 'they' do that?"

Do they look at the "signature" of the burst to get an idea of how powerful the actual strike was and then compare it with signal strenght?

EMWTK

I'm speculating, but I would think that different frequencies developed by the lightning strike are attenuated by the atmosphere at different rates. Perhaps by looking at the amplitudes of the frequencies generated, a good estimate can be made of the distance based on the attenuation ratios. I suspect you are right and they do comparisons to stored signatures.

Not only do you get ranging but direction and I think they get the direction with two antennas on the airplane. You only have to worry about one direction and that is the one in which you are heading.

Many moons ago, there was an article entitled "Spherics" which was published, I think, in "Circuit Cellar Ink" and gives schematics and the like for your pleasure.

Check out: http://216.239.51.104/search?q=cache:PglSM7r8ckwJ:

I think it's so old you may not be able to find the detail you want.

Al

-------------- Stormscope appears to be for aircraft - for storm avoidance- i.e. is there a storm ahead of me.?. The scheme that I mentioned requires triangulation - fixed stations used to detect position of lightning strokes i.e. is this storm in East Boondock and is it headed towards South Moose Wallow? Where should we expect to have to send forest fire fighters or utility linemen? Triangulation gives position as well as distance in an area of the size of Texas