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    Hi, I'm having a bit of trouble on this since I cannot understand the 2D diagram in my textbook.

    The diagram is of Hertz's radio wave experiment, using a metal loop with a gap in it for a detector. What should the orientation of this detector be however? Should the plane of the loop be parallel or perpendicular to the direction of propagation of the radio waves?
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    (Original post by 16Characters....)
    Hi, I'm having a bit of trouble on this since I cannot understand the 2D diagram in my textbook.

    The diagram is of Hertz's radio wave experiment, using a metal loop with a gap in it for a detector. What should the orientation of this detector be however? Should the plane of the loop be parallel or perpendicular to the direction of propagation of the radio waves?
    usually you want the plane of a loop antenna pointing at the transmitter, it should also be 90 degrees to the orientation of the elements of the transmitter dipole (if that's what you're using to transmit). Loops are often called magnetic loop antenna cos they pick up the magnetic component of the em wave.

    However I've seen a documentary reconstruction of Herz's experiment that had the loop flat on to the transmitter, I.e. wrongly orientated imo, either that's artistic licence or there's something I don't know about herz's apparatus *.

    Afaik Herz used both loops and dipoles at various times.

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    *quite possible
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    (Original post by Joinedup)
    usually you want the plane of a loop antenna pointing at the transmitter, it should also be 90 degrees to the orientation of the elements of the transmitter dipole (if that's what you're using to transmit). Loops are often called magnetic loop antenna cos they pick up the magnetic component of the em wave.


    However I've seen a documentary reconstruction of Herz's experiment that had the loop flat on to the transmitter, I.e. wrongly orientated imo, either that's artistic licence or there's something I don't know about herz's apparatus *.


    Afaik Herz used both loops and dipoles at various times.


    ---

    *quite possible

    Using a spark gap as a transmitter. The sparks are occuring vertically, so I guess that the electric component of the wave is oscillating in the vertical plane, the magnetic in the horizontal plane. Is that right? If so, then I would have the plane of the loop in a vertical plane, pointing towards the transmitter?
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    (Original post by 16Characters....)
    Using a spark gap as a transmitter. The sparks are occuring vertically, so I guess that the electric component of the wave is oscillating in the vertical plane, the magnetic in the horizontal plane. Is that right? If so, then I would have the plane of the loop in a vertical plane, pointing towards the transmitter?
    yeah, but I don't think that much radio emission comes out of the actual spark gap itself... but the spark direction was probably the same as the wires leading up to it.

    Hertz was definitely aware of Maxwell's equations and the speed of light had already been well constrained experimentally - he could have had a good stab at making a tuned dipole for his transmitter and from some of the pictures I've seen that's what his transmitter looked like.

    http://people.seas.harvard.edu/~jone...ertz_exp_2.gif
    https://en.wikipedia.org/wiki/Heinri...oscillator.png
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    (Original post by Joinedup)
    yeah, but I don't think that much radio emission comes out of the actual spark gap itself... but the spark direction was probably the same as the wires leading up to it.

    Hertz was definitely aware of Maxwell's equations and the speed of light had already been well constrained experimentally - he could have had a good stab at making a tuned dipole for his transmitter and from some of the pictures I've seen that's what his transmitter looked like.

    http://people.seas.harvard.edu/~jone...ertz_exp_2.gif
    https://en.wikipedia.org/wiki/Heinri...oscillator.png

    Thanks.
 
 
 
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