Search results
Results from the WOW.Com Content Network
Heading angle σ: angle between north and the horizontal component of the velocity vector, which describes which direction the aircraft is moving relative to cardinal directions. Flight path angle γ: is the angle between horizontal and the velocity vector, which describes whether the aircraft is climbing or descending.
High frequency (HF) is the ITU designation [1] ... It depends on the angle of incidence of the waves; it is lowest when the waves are directed straight upwards, and ...
When high-frequency signals enter the ionosphere at a low angle they are bent back towards the Earth by the ionized layer. [1] If the peak ionization is strong enough for the chosen frequency, a wave will exit the bottom of the layer earthwards – as if obliquely reflected from a mirror.
the incident angle (angle at which the ... Optimization is in the reverse order. First one does high frequency calculations to optimize the shape and find the most ...
The length is not critical, typically from one to two wavelengths end-to-end, but for any given length and frequency, there is an optimum acute angle at which the sections should meet. A horizontal rhombic antenna radiates horizontally polarized radio waves at a low elevation angle off the acute end of the antenna opposite the feedline.
The value of each data point in k-space is measured in the unit of 1/meter, i.e. the unit of spatial frequency. It is very common that the raw data in k-space shows features of periodic functions. The periodicity is not spatial frequency, but is temporal frequency. An MRI raw data matrix is composed of a series of phase-variable spin-echo signals.
In a dispersive prism, material dispersion (a wavelength-dependent refractive index) causes different colors to refract at different angles, splitting white light into a spectrum. A compact fluorescent lamp seen through an Amici prism. Dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency. [1]
The cone: The length of the cone should be a quarter wavelength of the antenna's lowest operating frequency. [2] The cone angle is generally from 25 to 40 degrees. The insulator: The disc and cone must be separated by an insulator, the dimensions of which determine some of the antenna's properties, especially on near its high frequency limit.