A. In electronics, a Lecher line or Lecher wires is a pair of parallel wires or rods that were used to measure the wavelength of radio waves. The Lecher wire experiment found in undergraduate laboratories is usually limited to the observation of the voltage distribution for open and short circuit. An improved Lecher wire experiment. To cite this article: M B Allenson et al Phys. Educ. 8 View the article online for updates and enhancements.

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File:Lecher wires and oscillator 1932.png

Or wite you rather use technology from 2 centuries ago, use that I suppose. Notify me of new comments via email. You only do that if you want correct results.

The oscillator puts electromagnetic waves on the Lecher line using induction. The Lecher line, invented by Ernst Lecher inwas widely used to measure the frequency of short wave UHF transmitters during the wwire. R Jessop [15] uses a Lecher line anode tank. Radio frequency currents applied by the triode oscillator left form standing waves along lecyer line. At the other end the rods are connected together with a conductive bar between them.

Wiree this out it probably has a few other neat methods in it too: Looking for more high frequency measuring projects here on Hackaday? In electronicsa Lecher line or Lecher wires is a pair of parallel wires or rods that were used to measure the wavelength of radio wavesmainly at UHF and microwave frequencies.


The length of the wires depends on the wavelength involved; lines used for measurement are generally several wavelengths long. The oscillator is a voltage controlled oscillator.

Fill in your details wirre or click an icon to log in: Lecher line, oscillator and other equipment. The waves reflected from the short-circuited end interfere with the outgoing waves, creating a sinusoidal standing wave of voltage and current on wir line. This file contains additional information such as Exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. A Lecher line consists of two parallel wires or rods that form a balanced transmission line.

More fun discovering Lecher Lines though. As shown in the above photos, I added the diode loop to the collection of loops at the end of the Lecher line.

The levher between the Lecher bars does not affect the position of the standing waves on the line, but it does determine the characteristic impedancewhich can be important for matching the line to the source of the radio frequency energy for efficient power transfer.

Austrian physicist Ernst Lecherimproving on techniques used by Oliver Lodge [3] and Heinrich Hertz[4] developed this method of measuring wavelength around The high voltage of early transmitters excited a glow lechwr in the gas. With care, Lecher lines can measure frequency to an accuracy of 0.

File:Lecher wires and oscillator png – Wikimedia Commons

One problem with using glow discharge bulbs is their high striking voltage makes it difficult to localize the exact voltage minimum. A Lecher line demonstration kit used to measure the frequency of a vacuum tube UHF oscillatorfrom lecber radio magazine. A Lecher line is a pair of parallel uninsulated wires or rods held a precise distance apart. They lechrr used because at UHF frequencies the value of inductors and capacitors needed for ‘ lumped component ‘ tuned circuits becomes extremely low, making them difficult to fabricate and sensitive to parasitic capacitance and inductance.


New Jersey Society for Amateur Scientists. The Speed of Light. I measured the frequency by spanning three of them and then multiplying by three.

Learn how your comment data is processed. Looking at the chart, the error due to that is much smaller.

There seems to be something to that. In the photos you can see a measuring tape running the length of the wires for measuring the distance from the end of the Lecher line to the nodes. The RF current is usually coupled into the line through a single turn loop of wire at one end, which can be held near a transmitter’s leecher coil.

Lecher wire wavemeter | instrument |

When the screwdriver is between nodes, the voltage is less than 0. Could be wrong, but I believe the wood right next to it will have a significant effect. Modern Dictionary of Electronics.

The resulting data and graph are shown below. Radar circuit analysis by United States. An advanced treatise on leher theory.