Use your TV as a tornado detector

[snopes]

Comment: I received this a few years ago by email and have always wondered
if this is true. I do not live in an area that has many tornados, so have
never tried it.

TORNADO WARNING SYSTEM
Warm up the TV set and tune to channel 13. Darken the screen to almost
black.

Turn to channel 2 and leave the volume control down unless you have a
broadcaster on that channel. The TV becomes a tornado detector as
explained.

"As a storm approaches, lightning will produce momentary white bands of
varying widths across the screen. Color sets produce a colored band. A
tornado within 15 and 20 miles will produce a totally white screen and
remain white, or color on color sets.
Should this occur, turn off your TV set, take your portable radio and go
to a place of shelter immediately.

This system was discovered by Newton Weller of West Des Moines, Iowa after
twelve years of study. It works because every TV set has channel 2 set at
55 megacycles. Lightning and tornadoes generate a signal near this
frequency which overrides the brightness control Channel 13 is at the
"high" end of the frequency band and is not affected. This is why the
darkness must be set on that channel.

Keep a protable radio handy for emergency instructions and in case of
power failure. LIghtning will cause intermittent static on a radio tuned
on 550 kilocycles. A tornado will cause steady, continuous static.

The above was featured as the Safety Topic in a newsletter of Argonne
National Laboratory."

[hambubba]

Actually the electrical frequency of lighting is zero. The higher in frequency you "tune" above zero, the less effect you have. The lower VHF TV frequencies can be detectors, as can any AM receiver. There is also no way to differentiate between a small strike nearby, and a large strike farther away, just based on the electrical noise.

I didn't know tornados generated a frequency on their own; I suppose it's possible it's static electricity, but I wouldn't depend on a TV for reliable detection. Of anything.

[hambubba]

The Weller Method.

The bottom line is that the method provide completely unreliable in actual field tests. Did it work sometimes? Yes, but most of the time it did not -- it either indicated a tornadic storm when none occurred, or it did not indicate the presence of such a storm when in fact one was nearby. In meteorological terms, its success score was too low and its false alarm rate too high to be of use.

[Gibbie]

Just how old is that advice? Warm up your television? References to black and white tv? Even assume it's at all plausible could it work on tvs with cable? It sounds like something you'd expect from rabbit ears or a house antenna.

I didn't find any reference to it on the Argonne National Lab site but I haven't had much time to look yet.

Gibbie

Originally Posted by hambubba

Actually the electrical frequency of lighting is zero.

They generate EM pulses in just about every frequency band. I have studied lightning using frequencies starting at DC (field mill), up to optical (return strokes), and beyond into x-rays. Okay, I never had an x-ray detector, but some of my fellow scientists do.

A tornado does not have some "fundamental" frequency like that. Although you can use your radio, computer, or TV as a tornado detector: tune to a local radio/TV station and watch for tornado warnings. Or get a weather radio and let it detect the tornadoes for you.

[hambubba]

I should have clarified, didn't know you were going to spring that kung-fu science stuff on me! The frequency is zero. It's a DC current, whichever way it is going... the "bandwidth" - the amount of radio spectrum it takes up away from "zero hertz" - is tremendous. That's also called "splatter". The reason it may seem to be multifrequency is because of frequency absorption in different parts of the EM spectrum.

[Troberg]

They generate EM pulses in just about every frequency band.

Exactly. That's the way early radios worked, by connecting a morse key to a small spark gap. The sparks caused interference that was easy to detect as it more or less went all over the frequency spectrum.

Originally Posted by Gibbie

Just how old is that advice? Warm up your television? References to black and white tv? Even assume it's at all plausible could it work on tvs with cable? It sounds like something you'd expect from rabbit ears or a house antenna.

I didn't find any reference to it on the Argonne National Lab site but I haven't had much time to look yet.

Gibbie

I first heard this in the early to mid 70s. I tried then setting up per the instructions, but never got anything like what was described. Maybe I was just doing it wrong.

[Avril]

A much better idea is to have your television tuned to a local broadcast station that will provide actual information about approaching storms.

If a tornado comes close enough that you really need to take cover, you usually won't have time after the signals, but there are such signals, and for that you don't necessarily need a TV. Ears pop. There's the sound of a train far from any actual trains. The sky takes on the color of the ground (greenish if there's a lot of grass, reddish in the red clay parts of Oklahoma, brown where you have just plain dirt, etc.)

The whole thing sounds really impractical.

Avril

I grew up in Tulsa OK, and this was taught to me by my high school electronics teacher. Much of it does work. It requires a black and white, or color CRT television, (so far as I know. I haven't tried it with an LCD set, but with spring just around the corner, it might make for an interesting experiment). Tune the set to a completely empty VHF channel, turn down the volume, then turn down the brightness until you see only the rare 'sparkle'. If lightning strikes anywhere near you, to several miles away, the entire screen will light up for a moment.

This part of the 'detector' works very well. If you're using a color set, you don't get colored flashes, by the way...the color circuitry in the TV is disabled absent a color signal.

The tornado detection portion of this works, as it was explained to me, because once a tornado touches down, it creates a low resistance path to ground, (relatively speaking), and there are numerous discharges through that path, at voltages much to low to cause actual visible lighting, though still potent enough to light up the detector. (this of course would form the kernel of another snopsian debate)

I never got 'lucky' enough to have a tv set up, with power, and a nearby tornado to actually detect one with complete confidence. Those of you who live in tornado alley might keep this in mind, and give it a shot this year.

[UrbanLegends101]

The theory behind the concept has some validity and is some of the basis for the operation of StormScopes available for use in general aviation aircraft.

How accurate is the televison set? Dunno. Never used one. And yes, it does have to be a TV set connected to an antenna and not the cable system. Also, it would have to be an analog TV set. Digital TV sets simply won't work in this application.



See chapter two of:

http://www.seaerospace.com/bfg/wx500pg.pdf

[zman977]

Originally Posted by UrbanLegends101

How accurate is the televison set? Dunno.

I don't think I'd rely on it as a accurate warning system. I'll stick to my NOAA weather radio.

[Spam & Cookies-mmm]

Originally Posted by zman977

I don't think I'd rely on it as a accurate warning system. I'll stick to my NOAA weather radio.

Of course, that's fine for now. But after the 2012 apocalypse, will there be a NOAA? I seriously doubt it. We'll all be on our own. So I will file this advice with my emergency plans and try to find a small CRT TV for my kit.

[RichardM]

My method is to take my truck up to where I have a good view of the sky in the direction of where the storm is coming from (usually from the northwest). Then I keep a close watch out for wall clouds, rotation, transformer flashes, etc. If I see any of these, I key the microphone and report it to the RACES net.

[Stan The Man]

Originally Posted by Avril

The sky takes on the color of the ground (greenish if there's a lot of grass, reddish in the red clay parts of Oklahoma, brown where you have just plain dirt, etc.)
Avril

There's no science behind that.

[Avril]

I didn't mean just any green. I grew up in Oklahoma and it's hard to explain--some of that is "have to experience it to know"--but to my eyes there is "thunderstorm green" and "tornado green," and they're different. But whether there is science or not, should I ever see that mixture of bright green, brown, and red swirling around in the sky again, I'm not going to contemplate it much before I try to find a basement to wait it out in.

[AnglRdr]

Here's how your TV can work as a tornado detector: if, through your roof that has been blown off by strong winds, you can see your television flying through the air, your TV has detected a tornado.

And yeah, the color of a tornadic sky is something you know when you see it. It is different from any other storm I've seen before.

[Elwood]

AnglRdr, I wish I could "like" comments on ULMB. I almost needed a new keyboard from that one.

[jimmy101_again]

Originally Posted by hambubba

I should have clarified, didn't know you were going to spring that kung-fu science stuff on me! The frequency is zero. It's a DC current, whichever way it is going... the "bandwidth" - the amount of radio spectrum it takes up away from "zero hertz" - is tremendous. That's also called "splatter". The reason it may seem to be multifrequency is because of frequency absorption in different parts of the EM spectrum.

Actually, most lightning strikes are more like AC, not DC. There is a sky to ground strike quickly follower by a ground to sky strike. It isn't required that the current flow reverses direction, the changing potential and current magnitude qualifies as AC. Voltage and current are not constant during the strike which would normally also be described as AC. There is a very fast rise and fall in the current (which is also AC'ish) that in turn probably gives rise to the large mount of RF noise the lightning generates.

But the best definition of lightning is probably that it is neither AC or DC. Nature doesn't really know what those terms mean, they are human concepts used to categorize (imperfectly) things, not immutable concepts from physics.

[hambubba]

Heh. Old Post Week? I honestly can't duplicate my thinking from these posts in '07. I'm wondering if the stroke I had knocked somthin' looser.

In any event, the new digital TVs won't detect signals, let alone lightning or tornados.