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How antenna height is related to frequency of the antenna with which it operates?
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Why antenna height is at least quarter wavelength for radiating from it?
A transmitter antenna is a tuned circuit and it can be very complex and it even get more difficult at higher frequencies, if it's not a 1/4 wave length of the transmitter frequency it is un tuned and you will have some of your RF power radiated back to the transmitter, that is called SWR, for Standing Wave Ratio and it will damp the RF that is radiated from the antenna and if the SWR is to high it can damage the transmitters final stage. It don't have to be the real physical 1/4 or 1/2 wave and it can even be 5/8 of the wavelength but then a L/C circuit have to be inserted at the input side of the antenna to tune the antenna to the correct frequency one antenna can even be used for two different frequencies, then a L/C tuning circuit have to inserted at a 1/4 wave length of the higher frequency , this type of antenna is used in duplex systems, like a cell phone.
AM radio and FM radio?
AM stands for amplitude modulation, while FM stands for frequency modulation. In AM, the amplitude (the height or depth of the crests or troughs) changes, while in FM, the frequency changes.
What is modulation why do we need modulation?
Sometimes we have to send low frequency information, like the tone of the voice of someone talking on a telephone, over a specific channel that only permits a specific high frequency, such as radio frequencies (RF). So how do we do that? One simple, cost effective, and bandwidth efficient method is to change, or modulate, a known RF signal a certain way. Some common ways of modulating such a high frequency signal are Amplitude Modulation and Frequency Modulation. Each of these modulation techniques has its own advantages and disadvantages and are therefore more useful in certain applications.
In power stations what does the flickering lights on boiler chimneys signify?
The flickering lights on boiler chimneys in power stations are aircraft warning lights. The spacing and blinking frequency are chosen to signify the height of the obstruction.
What is need to modulation in communication system?
Need for modulation 1) to reduce the antenna height 2) to multiplex the more number of signals 3) to reduce the noise & distortions 4) to narrow banding the signal 5) to reduce equipment
What is the relationship between frequency and antenna height?
For horizontal antennas operating below 30 MHz the optimum height is half a wavelength, so the height in metres would be 149.9/Frequency in MHz.
When a short grounded vertical antenna has a length L which is 0.05 1 at frequency f and if it's radiation resistances at f is R Ohms then its radiation resistance at a frequency 2f will be?
In ideal conditions the radiation resistance of a short antenna is proportional to the square of the height in wavelengths. So doubling the frequency would produce 4 times the radiation resistance. Rr is 1578(He/lambda)2 for a short antenna, He < lambda/8. He is the effective height, equal to half the physical height for a simple monopole, rising to the physical height for a monopole with an infinite amount of horizontal top loading.
How you find an height of antenna cb?
trigonometry
What are the needed specs for the rf cable to elevate its omni-directional antenna to the maximum height using a 30 watt vhf 136-174 mhz repeater?
Set the antenna at 1/4 wavelengths high to the specific frequency that you want to use. Cut the coax feed wire to multiples of 1/2 wavelengths of the specific frequency that you want to use,
Relation between wave length and size of the antenna?
To decrease antenna height For transmitting a signal of wavelength λ the antenna height must be λ/4. So if we want to send a 1 Hz (λ=3*10^8 m) signal ( very very low frequency) using an antenna , its height must be 75,000 Km ( impossible to build such a huge antenna ). If the same signal is modulated to some high frequency say 88 MHZ ( λ = 3.4 m ) , antenna height needed is 0.8522 m (quite easy to construct !!! ) (88 MHZ is the starting range of Frequency modulation which exists upto 108 MHZ).
How tall is the antenna on the Empire State Building?
The height of the Empire State Building's antenna is 204 feet.
What is the antenna height of RX 93.1?
while receive is not that important, transmit/receive is proportional here is the formula 234 divided by the frequency in Megahertz= length in feet 93.1/234=2.51 feet or 30 inches
Write a short note on antenna effective height?
Antenna height is defined as the ratio of the induced voltage to the incident field intensity for maximum reception. H=Voc/E m
Why antenna height is at least quarter wavelength for radiating from it?
A transmitter antenna is a tuned circuit and it can be very complex and it even get more difficult at higher frequencies, if it's not a 1/4 wave length of the transmitter frequency it is un tuned and you will have some of your RF power radiated back to the transmitter, that is called SWR, for Standing Wave Ratio and it will damp the RF that is radiated from the antenna and if the SWR is to high it can damage the transmitters final stage. It don't have to be the real physical 1/4 or 1/2 wave and it can even be 5/8 of the wavelength but then a L/C circuit have to be inserted at the input side of the antenna to tune the antenna to the correct frequency one antenna can even be used for two different frequencies, then a L/C tuning circuit have to inserted at a 1/4 wave length of the higher frequency , this type of antenna is used in duplex systems, like a cell phone.
What happens when the ball is served above the height of the antenna in volleyball?
Nothing, the ball is still in, unless the ball hits the antenna. If the ball hits the antenna at any point. The ball is called out.
What does the height of a bar in a histogram represent?
The frequency density. That is, the frequency divided by the class width.
Does an ungrounded antenna near the ground act like a single antenna with twice the height?
A better simple approximation would be two antennas separated by twice the distance of the single antenna to the ground.
