Electricity – Propagation of Decimeter Waves Along Lines

Determine and investigate the current and voltage on a Lecher line.

In the experiment, a Lecher line open at the wire ends and a shorted Lecher line are investigated. The waves are reflected at the ends of the wires, so that standing waves are formed. The current is zero at the open end, while the voltage is zero at the shorted end. The current and voltage are shifted by λ/4 with respect to each other, i.e. the wave antinodes of the voltage coincide with the wave nodes of the current. The voltage maxima are located using a probe with an attached incandescent lamp. An induction loop with connected incandescent lamp is used to detect the current maxima. The wavelength l is determined from the intervals d between the current maxima or voltage maxima. We can say d = λ/2

A transmitting dipole (λ//2 folded dipole) is attached to the end of the Lecher line. Subsequently, it is no longer possible to detect any voltage or current maxima on the Lecher line itself. A current maximum is detectable in the middle of the dipole, and volt- age maxima at the dipole ends.

UHF wave generator
Lecher systems with accessories
Steel tape measure, l = 2 m/78"
Saddle Base (3)
Steel tape measure, l = 2 m/78"