Verifying the Radiating Long Solenoid with AC Current

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Discussion Overview

The discussion revolves around the theoretical and experimental aspects of radiation emitted by a long solenoid when subjected to a sinusoidal current. Participants explore the validity of this phenomenon, seeking both theoretical explanations and experimental evidence to support or refute the claims made.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant proposes that applying a sinusoidal current to a long solenoid results in radiation, seeking verification of this theoretical result.
  • Another participant shares a paper on loop antennas, suggesting that the inclusion of a ferrite rod enhances performance for AM radio frequencies.
  • A different participant references a paper from the American Journal of Physics and inquires about the fundamental differences between fields that produce radiation and those that do not.
  • One participant discusses practical applications of antennas made from tubing and wire, noting their use in vehicles and the need for experimentation to determine resonant frequencies.

Areas of Agreement / Disagreement

The discussion does not reach a consensus, as participants present varying viewpoints and references without settling the question of whether the radiation from a long solenoid is valid or not.

Contextual Notes

Participants express uncertainty regarding the theoretical underpinnings of radiation from solenoids and the efficiency of different antenna designs at various frequencies. The discussion highlights the need for experimental validation and deeper theoretical understanding.

Who May Find This Useful

This discussion may be of interest to those studying electromagnetism, antenna theory, and practical applications of solenoids and antennas in engineering and physics.

sanjibghosh
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Recently I found that, if I apply a sinusoidal current to a long solenoid I get a radiation from it. It is completely theoretical result. I want to verify whether my result is correct or not. For this verification I need either some experimental result or some theoretical explanation whether it is wrong or correct,if correct then why this is happening?
please ,please help.
please.
 
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Here is a paper on loop (solenoid) antennas, including estimate of radiation resistance..
http://sidstation.lionelloudet.homedns.org/antenna-theory-en.xhtml .
Put a ferrite rod in it and it works better for AM radio (~1 MHz).
 
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I got the point and also I found a paper on this topic in American Journal of Physics-1995. One thing I want to know, What the basic difference between the field with radiation and without radiation is.
 
It is also fairly common to use a long piece of tubing and wind a spiral of wire onto it to act as an antenna for vehicle use.
Such antennas resonate at much lower frequencies than the length of the antenna would otherwise allow.

Blank fishing poles made of fibreglass are commonly used and the wire is wound onto the fishing pole with some spacing between turns of wire. It is usually fed from a transmitter via a coaxial cable at the bottom.

These antennas are not very efficient at low frequencies but they do work.

Usually, the resonant frequency has to be found by experimentation but a good start is to wind on about one quarter wave length of wire onto the rod and then mount the rod over a flat metal surface (a ground plane) and test it for resonance and maximum radiation.
 

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