Predicting tornado with TV

[cuffs054]

Many, many years ago I remember my Mom trying to do something with the TV's (we're talking BW and outdoor antenna) that was supposed to predict tornados. It was something like tuning TV to channel 2, lowering the brightness just till screen went dark and then switch to channel 13. The idea IIRC was that nearby lightning would cause a white bar across screen. If the screen went totally white, you best duck and cover.
Anybody remember this?

never mind...

http://usatoday30.usatoday.com/weather/wtwistqa.htm

 

[frigilux]

I absolutely do remember this technique for detecting tornadoes. It was a long time ago---probably the 1970's---and I'd forgotten about it until now. Fortunately, I wasn't near enough to a tornado to see the screen go white. The article you linked to pretty much debunks the theory, anyway.

The days of seeing a big antenna atop every roof seem so long ago.

 

[kb0nes]

I recall hearing of using a TV to detect lightning, when I was little one of my older brothers showed me that trick. It can't directly predict a tornado since a tornado does nothing to alter the frequencies a TV receiver operates at...

Of course today's TV's won't do this since they no longer have receivers that respond to amplitude modulation like the old NTSC receivers did. A modern ATAC digital receiver won't see anything unless it gets enough valid signal to lock onto.

Those with older TV's can still use this method, and it probably works better now that there are almost no low band TV (under channel 5) stations to cause interference to the lightning interference.

Of course as far as predicting a tornado goes, a modern TV would be better, assuming its tuned to a channel where they are broadcasting weather information for your area!

 

[tolivac]

Guess what-----Digital TV STILL uses Amplitude modulation of the carrier to convey the signal-FM modulation would require too much bandwidth. The digital pulses can be seen on a spectrum analyzer tuned to the stations frequency.There is only one carrier now-the sound is digital with the picture.In the older NSTC analog system-a seperate carrier was used for sound-FM modulated.An analog TV "transmitter" was essentually two transmitters used as one.Their outputs were combined into a diplexer-the diplexer out fed to the transmission line up the tower to the broadcast antenna.The tornado and storm activity indicated by TV's must be a reaction of the highly ionized air around the receiver-causing the screen to glow.I have never seen it-but some of my freinds who were in tornadic activity saw their TVs glow from the storm-the TV wasn't on.

 

[kenmoreguy89]

If it would actually work, that would just predict a storm producing many lightening...not a tornado approach assured.
Despite tornadoes are produced from cells that usually produce considerable electric activity (because of their power and conformation)we also recognize many storms that even if are tornado producers does not have that much of lightening or electric activity, moreover there're storms or the so called "lightening storms" that produces lots of lightening as the name says, but no tornadoes, just electric activity...these are common pretty much worldwide even in not tornadic countries/areas.
It is not completely non-sense anyway, tornadoes have always been associated to the usual electric activity of tornadic cells as I said, but electric activity does not absolutely mean an imminent tornado approach always, nor absence of considerable lightenings means no tornado risk.

[this post was last edited: 6/13/2013-18:09]

 

[whirlcool]

The days of seeing a big antenna atop every roof seem so long ago.

They have been replaced with satellite dishes!

 

[tolivac]

Antennas are starting to make an occasional comeback due to "free"terrestiral HD digital TV broadcasts.You can get an antenna that fits onto the edge or back of your sat dish.Since the digital TV broadcasts are mostly moved to the UHF band-the newer antennas are smaller.Then---there is always cable-no antennas or dish required.-but you have to pay monthly for these.The digital broadcast TV change caused a lot of analog TV transmitters to be scrapped-almost like being put on the curb like an old washer or dishwasher-one station did that!I salvaged what parts I could from their transmitter.It yeilded several very powerful fans and blowers.

 

[kb0nes]

I still have a TV antenna

I receive all my locally originated channels via direct HD broadcast with a small roof mount VHF/UHF antenna (we have 2 VHF HD channels in our market). I figure there is just no justifiable reason to view a signal after it is uplinked, repeated and then downlinked by DirecTV satellite. This only allows for more degradation, commercial injection and rain fade.

In fact since the HDTV changeover our local PBS station has several sub channels now. The odds of finding watchable programming on direct broadcast TV are higher now. I now toy with the idea of no longer paying for the satellite service.

For those that are receiving your locals via cable (or satellite) I always suggest the experiment of trying to receive them directly off air. In many cases the picture quality is far better then cable. The cable company is often receiving the same off-air signal then running it through scads of processing, amplifying, distributing and many miles of cable. NONE of that can make the picture better then what hits your own antenna! And of course the cable company greatly increases the odds of downtime too. With the exception of rain fade, the satellite companies tend to have lower downtime then cable. They have a lot more redundancy built into their systems.

In my opinion everyone should have an antenna to receive your locals. If you ever had a wide area emergency relying on the cable company to give you service is dicey. As Rex mentioned the majority of the HD stations today are in the UHF band so antennas are smaller. The only drawback is that the UHF signals don't penetrate structures as well so indoor and attic mount antennas may not be as usable in some cases.

 

[tolivac]

At my workplace we have a new TV that can tune the local stations-used mostly in hurricane season to monitor hurricane activity.As said before Sat and cable broadcasters are useless for giving local weather conditions or other local emergencies for that matter.I don't like cable either---it is so "buggywhip" technology!!Why bother with it.The cable infranstructure is far more expensive to maintain than one transmitter and antenna that could serve the same area.The cable tech should be abandoned.Some of the lucky TV stations were assigned high band VHF frequencies-this is easier for them.And for the listener,too!VHF transmitters are cheaper to run(efficiency) than UHF ones.-and less power required to serve the area.Cable broadcasters also tend to get noisey-the cables are targets for all kinds of electrical noise.

 

[arbilab]

If your TV flies out a hole where your roof used to be, you're probably in a tornado.

 

[tolivac]

You will most likely flying out of the hole in the roof with your TV!