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MIT Physics Demo -- Dipole Antenna
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- čas přidán 7. 08. 2008
- An RF transmitter is connected to a long antenna, emitting radio waves. A dipole antenna with a light bulb between its elements acts as the receiver. When the receiving antenna is parallel to the transmitter, the radio waves are absorbed, creating a current in the antenna and causing the bulb to glow. When perpendicular, no current is created, and the bulb does not glow.
See the original video on MIT TechTV - techtv.mit.edu/...
i think there is a cos(theta) function involved somehow, which is like an attenuation of the signal. basically, the current picked up in the recieving antenna/lightbulb is a dot product of its direction and the direction of the electric field: max when aligned, zero when perpendicular - that's because cos(theta) is 1 at theta=0 and 0 at theta=90 degrees
Cross Polarization causes ~20db decrease in siganl strength hence the dimming of the lightbulb.
It is just a polarization loss factor (PLF) that you are seeing. It is equivalent to spraying a beam of water horizontally through a vertical opening. Almost no water goes through. But in this case, the dot product of two perpendicular beams would be exactly 0. So, at normal incidence, there is no transmission,
Everything the wave touches divides the energy multiples the frequency the light has too much resistance to movement the inertial is no longer great enough to create what we see as the future - energy divider frequency multiplier the voltage is increasing the amperage is decreasing
I dont mean wave I mean inertial
The transistor is the only proofable thing that exists - its our fastest memory our longest memory We are inside ourselves We are just formular's for the machine
a beautiful device
weight
Hmmmm.... Great Demo of the dipole ant.
John
great demo....is the antenna horizontally polarized? Also, what is the radiation pattern for it in the H-plane? Would it be the same as the radiation pattern in the E-plane had it been vertically polarized?
Don't know much here! (1) Will the dipole work setup in vertical with radiator on top? (2) Say becoming omni better signal to vertical receiving antennas? (3) In vertical how much gain is lost or does the 1/2 wave dipole have any gain? Anyone help? Thanks.
how can we build this?
really great
is there a circuit for the transmitter
Seems like a lot of trouble just to turn on a light bulb.
you have to turn on wirelessly!!! thats the trouble here
is it possible to buy such RF transmitter?
SALVE SALVE JAMES!!!
Awe come on, he's got a small watch battery & a mercury tilt switch in the portable dipole!
LOL - J/K!
I thought I was smart until I read the comments. I really need to study electricity more, my worst unit in Physics.
Is it me? NO AUDIO
:0 genial
👍
Sorry, but you have to learn the basics before getting into the big stuff. Experiments like these, while done before, are the foundation of the "current" technology you speak of.
poor tesla, they couldnt even put your name in the tags lol. hey if anyone wants to learn about teslas wireless transmission of electicity on the earth and interplanetart energy transfer just come over to my site, if you love tesla and radio you will love my videos! thanks poor tesla,
Wouldn't be standing in front of that for too long pal. Mind your goolies!!!
Tesla did this about 100 years ago, big deal. Now it takes MIT kids with current technology to do this? When did science become like a religion and rigidly opposed to new ideas?