What is maximum usable frequency in antenna?
What is maximum usable frequency in antenna?
MUF (Maximum Usable Frequency) is the maximum frequency which can be reflected for given distance of transmission. MUF is usually 3 to 4 times of critical frequency. Q. 2 Explain Yagi-Uda antenna with the help of the neat diagram.
What is the critical frequency of ionosphere?
Critical frequency is the highest magnitude of frequency above which the waves penetrate the ionosphere and below which the waves are reflected back from the ionosphere. It is denoted by “fc”. Its value is not fixed and it depends upon the electron density of the ionosphere.
What is virtual height in antenna?
The apparent height of a layer in the ionosphere, determined from the time required for a radio pulse to travel to the layer and return, assuming that the pulse propagates at the speed of light.
How is MUF determined?
The MUF for a certain distance on the Earth’s surface can be determined by multiplying the critical frequency of the layer in consideration by the corresponding M-factor.
What is luf antenna?
The lowest usable high frequency (LUF), in radio transmission, is a frequency in the HF band at which the received field intensity is sufficient to provide the required signal-to-noise ratio for a specified time period, e.g., 0100 to 0200 UTC, on 90% of the undisturbed days of the month.
How do you find the maximum frequency of a signal?
Once a continuous signal is sampled at frequency fs=1/Ts (here Ts= 125 nanoseconds), the maximum “observable” frequency of the sampled signal, without further hypotheses, is indeed half the sampling frequency.
What is the value of maximum usable frequency when the incident angle is 60?
What is the value of maximum usable frequency when the incident angle is 60° and the critical frequency is 4.5MHz? Explanation: MUFfMUF = fcsecθi = 4.5MHz ×sec60=9MHz.
What is the critical frequency if the maximum number density of electrons is 1012 m 3?
The correct option is (C) 27 MHz.
What is a duct propagation?
Duct propagation is the phenomenon of transmitting UHF and VHF signals to longer distances. Basically, the wave propagates inside a duct by undergoing successive refractions inside it. The change in the refractive index due to warm and cool layers in the atmosphere causes duct propagation.
What waves bounce off the ionosphere?
The ionosphere is a region of the upper atmosphere where there are large concentrations of free ions and electrons. This region reflects medium and short wave radio signals, bouncing them back towards the Earth and enabling these radio communications to be heard over vast distances.
What is critical frequency MUF and OWF?
Frequencies including the Critical Frequency; Lowest Usable Frequency, LUF; Maximum usable frequency, MUF; and the Optimum Working Frequency, OWF are all of great importance when determining which frequencies will provide the best performance for a short wave radio, HF radio communications link.
Why is critical frequency important in HF radio?
As such an overview of these terms is of importance to anyone using HF radio communications. The critical frequency is an important figure that gives an indication of the state of the ionosphere and the resulting HF propagation. It is obtained by sending a signal pulse directly upwards.
What is lowest usable frequency (LUF)?
These two effects mean that there is a frequency below which radio communications between two stations will be lost. In fact the Lowest Usable Frequency (LUF) is defined as the frequency at below which the signal falls below the minimum strength required for satisfactory reception.
