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Long-distance radio communication Amplitude Modulation (AM) is the answer, because Frequency Modulation (FM) works at frequencies greater than from 50 MHz and can only be used for line-of-site communication, although it can be used to communicate for long distances into space.
For long-distance communication, AM and Single-sideband (SSB) modulation can be used in the high-frequency (HF) range in the region of 30 MHz, but the distance is limited to about 30 to 100 kilometers. If ionospheric conditions are good, however, communicating with someone at the opposite side of the globe is possible, because radio signals bounce off the ionosphere back to the Earth and then back to the ionosphere. This phenomenon is called "skip."
If you desire continuous long-distance communication, you need to use the lower band of the RF spectrum: long-wave, medium-wave or short-wave signals. With AM, these frequency ranges are not affected by obstacles like mountains or buildings and are called ground waves, because they follow the contour of the Earth. Hence, with enough power and a good directional antenna, it is possible to communicate around the Earth. The only problem is Static-interference (QRM) on the received signal that can make clear communication next to impossible. Sunspots and other sun activities can also affect this type of communication and can even blank out communication totally, a phenomenon known as "radio silence."
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What is ture of the relationship between frequency and wavelength?
Wavelength lambda and frequency f are connected by the speed c of the medium. c can be air = 343 m/s at 20 degrees celsius or water at 0 dgrees = 1450 m/s. c can be light waves or electromagnetic waves = 299 792 458 m/s. The formulas are: c = lambda x f f = c / lambda lambda = c / f
Would a donkey be able to run as fast as a horse?
probably not because most horses are built for speed and donkeys are not
What is true about the running duration and frequency?
The running duration and frequency should be tailored to an individual's fitness level and goals. Generally, beginners may start with shorter durations and lower frequency, such as running two to three times a week for 20-30 minutes, while more experienced runners may run longer and more frequently. Consistency is key for building endurance and improving performance, but it's also essential to allow for rest and recovery to prevent injury. Balancing duration and frequency can help achieve optimal results in a sustainable manner.
Are these two stimulus pulses different as regards their parameters of intensity and duration?
To determine if the two stimulus pulses differ in intensity and duration, you would need to compare their specific measurements. Intensity refers to the strength or amplitude of the pulses, while duration pertains to the length of time each pulse lasts. If one pulse has a higher amplitude or a longer time span than the other, they would be considered different in those parameters. Without the exact values or descriptions of the pulses, it is impossible to conclude definitively.
Why electricity is produced upto 6.6kv or 11 kv in power plant but our requirement is only 440 volt?
It is mainly for transportation, especially over longer distances, that higher voltages are used. At higher voltages, less current is required - and power losses are proportional to the square of the current.
Why amplitude modulation used for long distances?
AM travels well over longer distances than FM is capable of, but has a lower fidelity and is more susceptible to metal, which is why it is not used as often in cities.
What is an AM transmitter?
Aplitude ModulationAn AM transmitter is a Amplitude Modulated transmitter where the amplitude of the Radio Frequency signal is modulated, usually used in the lower frequency bands where the frequency is to low for Frequency Modulation (FM), it was the first type of modulation used in radio communication FM was developed in the late 1950's and is not sensitive to static interference as AM AnswerAM is Amplitude Modulation that is the RF signals amplitude is modulated with the audio signal. this modulation is done because the audio signal being of low frequency cannot be transmitted to longer distance so the audio signal is amplitude modulated with RF signal and then transmitted into the air
What are the similarities and differences between AM and FM waves?
Both AM (amplitude modulation) and FM (frequency modulation) are methods to add information to a carrier wave. The main difference is how they encode this information: AM varies the signal's amplitude, while FM varies the signal's frequency. AM is more susceptible to interference but has a longer range, while FM is less prone to interference and offers better sound quality.
What is frequensy modulation?
Frequency modulation (FM) is the process whereby the frequency of a radio wave is changed (modulated) rapidly as a result of the changes in the sound that the radio is designed to transmit. In the 'old days' the height of the wave (amplitude) would be modulated to provide a changing signal that could be changed into variable sound by a suitable reciever. This is called amplitude modulation (AM). However, more recently (like 40 years ago) it was found that increasing the frequency to levels known as very high frequency (VHF) and modulating the frequency rather than the amplitude would enable a better quality of transmissions. Also, the higher frequencies meant that radio waves did not travel so far so were less able to interfere with transmissions from other radio stations. The lower the frequency the longer the wavelength and some of the longwave radio transmissions will travel very long distances. The VHF transmissions of today require repeater transmitters located around the country.
Where is amplitude modulation used?
we have two types of signals namely the message signal and the carrier signal. so if the amplitude of the carrier is varied in accordance with the instantaneous value of the message signal then it is known as the amplitude modulation.if we want to transmit our message signal to long distances we need to do modulation and hence amplitude modulation is done. by amplitude modulation we generate side bands which consists of the part of the message which signal which is demodulated at the receiver to get back the original message signal we are using this amplitude modulation in radio communication. It will work in the traffic also with out disturbances but frequency modulation didn't work without disturbances.
What are diffrence between AM radio waves and FM radio waves?
AM stands for "Amplitude Modulation". The sound signal you hear is transmitted by modifying the amplitude of the carrier frequency.FM stands for "Frequency Modulation". The sound signal you hear is transmitted by modifying the carrier frequency itself.AM uses a 5Khz bandwidth with additional space to allow for signal separation avoiding interference between stations.FM requires a wider bandwidth.AM has lower sound quality and is subject to static from weather conditions and adjacent frequency radio transmissions.FM has wider bandwidth per channel, due to the better ability to separate noise in the FM bandwidth.AM has a longer range than FM and with the correct conditions can bounce a signal off the ionosphere allowing for longer range possibly causing interference with far away radio stations on the same frequency.FM signals line of site only and will drop of after about 50 miles from the station as the earth curves away. To compensate for this, broadcasting stations use high transmission antennas.
What are the relationships between the frequency of a simple pendulum and its mass amplitude and length?
The lower the frequency, the larger mass and longer length, The higher the frequency, the smaller the mass, and shorter the length.
Why is Frequency Modulation operated at such high frequencies when compared to its Amplitude Modulation counterpart?
Frequency modulation is better suited for high frequency apps for better quality of service longer range and penetration through solids and better control over TX or Transmit gain levels that can be hazardous at high power ANSWER 2 : I think its more about history . AM was used since the 1920's through WW2 , operating range was between 400khz to 50mhz . FM "Broadcast" Band came much much later although the idea of Frequency Modulation was old by then . If you were to modulate a typical 75khz FM signal (music) , it would take up the space of 6 AM stations on the old band . Operating up in the VHF frequency range meansMUCH smaller antennas and less power (although signals are more line of sight and would not travel as far as the AM stations , this is about frequency and not mode . FM has a much better signal to noise ratio so you will have better range on THE SAME FREQUENCIES with FM .
What is the diffirences for the listener between AM an FM?
AM and FM both are used in radios. They work in same principles, except FM is frequency modulation and AM is amplitude modulation. FM is much better than AM because it can travel a longer distance before dispersing.
If a wave has a low frequency does it have a short wavelength?
The product of (frequency) x (wavelength) is always the same number ... the speedof the wave. So the lower frequencies must have longer wavelengths.
Why do low frequency waves travel longer distances?
High frequencies are more damped by air than low frequencies.
Why AM travels more faster than FM?
AM and FM are methods of delivering signals embedded in a carrier frequency. There are many applications for them but they are best known for radio applications AM means amplitude modulation. In this technique, the amplitude or height of the carrier signal increases and decreases as the base signal changes. AM radio signals will travel great distances so a single transmitter can cover large areas. FM means Frequency Modulation where the frequency of the carrier signal increases and decreases to represent the change in voltage of the base signal. FM signals tend to offer better signal quality than AM but the range is far less, demanding multiple transmitters to cover the same area as one AM transmitter.
