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12.13.2007
Calling All Scientists
Weird phenomenon this morning. I'm driving down the highway and notice that my exterior antenna is shaking back and forth in a violent manner. I'd never seen that before no matter how windy it was. This goes on for a couple of minutes and then it stopped for a while. Then the shaking returned. The cycle repeated itself throughout the journey.
So I started to notice other cars that passed me. Some had the possessed and shaking antennas. Some did not.
Ice was building up on my antenna due to the fog, but that's the only unusual thing.
Ideas? I'm telling ya, it was weird.
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I noticed that this morning too! Passed an 18 wheeler that had a huge antenna that was doing it and thought it was weird. Then had another pick up pass me and his was doing it like crazy. Mine was covered in ice and just stayed still. It was very strange as it didn't seem that windy out.
Uh, it was because ice was building up on your antenna, increasing the weight and, subsequently, the amount of movement. The violent whipping would eventually dislodge the ice and then the process started over.
I don't know what was causing it, but I saw the same thing this morning.
Mine did the same thing this morning.. I thought it was going to fly off it was whipping so violently!
It's Bush's fault.
If you will look at your antenna it is shaped to not react as such in normal conditions. The ice buildup on the antenna alters the
aerodynamic design therefore causing the weird gyrations.
IN a nutshell, it's called harmonic resonance, also referred to as an Aolean(sp?)Harp when the power lines do this and "sing". It is the same thing that caused the Tacoma Narrows bridge in Washington state to collapse back in the late 30's/early 40's. The shaking is dependent upon the fundamental frequency of the medium, be that an air column in a clarinet, a guitar string, or in your case, an auto radio antenna. In this case, the air passing around the medium creates a standing wave pattern that causes the antenna to vibrate back and forth @ it's fundamental frequency; change the speed, and the air wave pattern does not achieve the fundamental frequency. And this fundamental frequency is determined by the length of the antenna.kaw
Mine was doing it too. It had more ice at the top than at the bottom. I think that the weight of the ice on top caused the resonance, which caused the waving.
Same thing happened to my weeny when I was peeing off the back porch this morning. It started shaking violently. Afterwards, I smoked.
Adendum to my 9:56: add "and the diameter (how much ice) is on the antenna" to the last line.
My Republican antenna was standing nice and straight.
What you are seeing is the oscillation of a flexible structure caused by the delta of low pressure and high pressure areas formed around it resulting from the drag of the atmosphere as you provide the thrust by driving your vehicle at varying speeds down the road. The accumulation of matter, being it ice, or even bug guts, can cause an infinite amount of variations to the drag coefficient as can the speed of the vehicle and the speed of the wind relative to the vehicle. The constant, minute variations in air pressure along the shaft of the antennae cause it to oscillate until the pressures are equalized along the shaft to the point where the natural rigidity of the material making up the shaft is no longer affected by the pressure variations. Have you seen the old videos of bridges wobbling and collapsing in high winds??? It is the same concept on a smaller scale.
Does this drive you nuts???
Solution: Attach something to the top of your antennae, like a Jack in the Box ball or a ribbon. (I use one of my wife's old tassels from her dancing days at the T&A Cabaret) The significant increase in drag at the top the antennae will dominate the lesser pressures along the shaft causing it to bend naturally in the opposite direction of the pressures being applied to it and will eliminate the oscillation of the antennae.
Double Fake Mr. Wizard
9:56... Can you run that by me one more time?
Is this going to be on the final exam???
The bridge in Washington was called Galloping Gertie by the locals. The bridge had a history of wobbling on windy days from the time it opened to the day in collapsed.
10:06...hilarious!!!!
Barry, you need to get satellite radio.
Barry, MzChief, the BOLD, just put a hex on your antenna. That explains it.
And yes, 10:06, that WAS hysterical.
WRITE THIS DOWN! Driving on the "rumble strip" will cause your antenna to shudder.
Global warming?
Ok..I don't know about your antenna but I have a better one. This totally freaked out my husband and I. Last Saturday morning we were going down 287, almost to I-35 when instantly our truck windows fogged up. All of them. Completely. Instantly. My husband thought the cab was filling with smoke. It was the strangest thing. We figured out we were right at the edge of a cold front because it went from 55 to 73 degrees within a half a mile. It was still freaky though.
I enjoy the icy antenna talk! It made my pants vibrate in a violent whipping motion until they went around the room and then it started all over again.
Yea, it is kinda like they said about the oscillating whatever. On rare ocassions I have seen power lines and overhead phone line do it on extremely windy days. I have never seen it at night, but it is dark. Guess I was misinformed. I was told it was called Wind Turbulence Fluctuation. WTF for short.
When you were buying your car, they asked if you wanted Onstar and you thought they asked if you wanted Gaydar.
The next time it gets foggy it will do the same thing. Air is thicker when it is full of moisture
1:44 - just too funny.
Flying pants? I assume you were in them.
Whee, what a ride!
:-)
Yea, Martha I saw a feller stopped on highway 287 this morning and wiping his antenner
now I know why
Heheh 10:06!
9:58 has a friendly antenna. It waves instead of wobbles.
Nice. It has Democratic instincts.
NICE TO KNOW THAT EVERYONE WAS WATCHING THEIR ANTENNAS INSTEAD OF THE ROAD THIS MORNING - YIKES!!!!
Mine did the same thing. I just kept praying it wouldn't come back & slap my windshield & shatter it.
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