The topic "FM vs. AM" was touched upon and what for. I could not resist and decided to leave a comment as a person who knows this business) Alas, the community is fenced off, therefore it was not possible to add a comment there. Therefore, I will post my answer here, I think someone will certainly be interested.
The answer should have been not to the post itself about the AM band, but to the comment-question of the user john_jack
:
To whom and for what did stereophonic broadcasting from a radio receiver surrender?
My answer is:)
Unfortunately, stereo and sound are important for the mass listener, because the AM band has become the lot of hobby radio amateurs who listen to all possible bands and know where which stations are broadcasting at what time. Well, pensioners, etc., as mentioned above ...
Nowadays, alas, this is not an element of mass culture, but a hobby for a small number of people. The capacities are often higher on NE than on FM (well, the territory is true too) - therefore, broadcasting eats more money and listen to it, alas, less than those for whom advertising is intended (it is for the masses, again, and usually one city, for example, in which the advertised store is located, the one who lives in another neighboring city will not go for the goods anyway because of the advertisement he heard). Which raises the question of profitability.
As a result of this, in these bands there were mainly state radio stations, either religious or amateur, broadcasting at the expense of subsidies from outside, and in no way paying for themselves in terms of advertising ..
If you, the author of the comment, are one of these above-mentioned people (for whom these ranges are not indifferent), then my respect and hello to you) But alas, there are few such people .... most do not even wonder what AM is on the receiver and why it is needed there. ..
In America, by the way, the situation is slightly different - there are a lot of talk radio stations, which just removes one of the above phenomena - that is, the sound quality is, in principle, not in the forefront (there is no music, the sound of instruments and vocals, etc., you don’t need to enjoy, it’s important just said information), plus the territory can be much larger than 1 city, especially in the evening (turn on the receiver after 23:00 at night - be surprised how many stations appear there in comparison with the daytime emptiness - all this sometimes flies thousands of kilometers !! due to the peculiarities of ours with you atmosphere above the ground, during the day the range is akin to FM - one city and its environs, and even then not always - in Moscow, sometimes local SV transmitters are caught with difficulty).
By the way, there is a lot of music on this range in the evenings, because sometimes songs are played at state stations, and more often they are not even as “pop” as on FM, which will definitely please those who do not like pop music. An example of a radio station broadcasting on HF (SW): http://xradio.su/slushat.html I heard them myself more than once, well done guys! Unfortunately, the HF (SW - Short Wave) range is less than the MW (MW - Medium Wave) - because it is not used in America.
If you are interested, there is also such a link - http://emwg.info there is a guide to the frequency of what and where it broadcasts in the European part of our continent in the NE band. To use this thing, I recommend a receiver with a digital scale, and not with an analog "arrow" floating past the approximate numbers, it will be easier to determine what you are hearing at the moment. The analog scale is also less stable and the reception quality is sometimes lower.
I think experts will immediately prompt and at the moment one of the best receivers on which you can listen and enjoy it all - type in the search engine the query "DEGEN DE 1103" do not consider the link for advertising, therefore I will not give direct links. As the owner of this thing, I declare that this is currently one of the best combinations of price / quality, on the road for me the thing is indispensable, if we talk about the radio (I'm not driving, because I have a pocket receiver, not a car one).
The radio tape recorders in cars usually, if they were not soldered, but went "immediately with the car" and the first owner did not carefully remove them, then they also work with a bang! No FM compares. With a "broken" radio tape recorder, before selling the car, they often simply forget to properly connect the AM_antenna, because the masses of the people are only interested in FM ...
A clean welcome to all those interested and hello to colleagues in the hobby! :-)
Broadcast bands
At the dawn of the development of radio broadcasting, powerful high-frequency vibrations were obtained using electric machine generators. These were ordinary electric generators, in which the number of pole pairs, the winding connection scheme and the rotor rotation speed were chosen such that the frequency of the generated signal was tens of kilohertz. At that time, radio tube transmitters had not yet received their development, and the electric machine method completely made it possible to obtain high-frequency oscillations of a high power level. True, the frequencies of these oscillations could not exceed the natural mechanical and design limitations, and, as a rule, such radio stations operated at frequencies below 100 kHz. By today's standards, these are ultra-long waves. Thus, the development of broadcasting began with the development of the lowest frequencies.
I will not delve into the historical development of the radio frequency spectrum for broadcast purposes. I will give it in full in the form of a table. Such a distribution of frequencies exists today.
|
Range |
Type of modulation |
slang name |
|
| LW (LW) | 144 - 415 kHz | Amplitude (AM) - mono DRM Digital Broadcasting |
- |
| SW (MW) | 520 - 1602 kHz | AM | |
| HF - 90 m | 3200 - 3400 kHz | - | |
| HF - 75 m | 3900 - 4000 kHz | - | |
| HF - 60 m | 4750 - 5060 kHz | - | |
| HF - 49 m | 5900 - 6200 kHz | - | |
| HF - 41 m | 7100 - 7400 kHz | - | |
| HF - 31 m | 9500 - 9900 kHz | - | |
| HF - 25 m | 11650 - 12050 kHz | - | |
| HF - 22 m | 13600 - 13800 kHz | - | |
| HF - 19 m | 15100 - 15600 kHz | - | |
| HF - 16 m | 17550 - 17900 kHz | - | |
| HF - 13 m | 21450 - 21850 kHz | - | |
| HF - 11 m | 25650 - 26100 kHz | - | |
| VHF - 1 | 65.9 - 74 MHz | Frequency (FM) with polar modulation of a stereo signal* | Russian VHF |
| VHF - 2 | 87.5 - 100 MHz | Frequency (FM) with pilot tone | Bottom FM |
| VHF - 3 | 100 - 108 MHz | FM |
Let's talk better about the features of radio wave propagation, the quality of the received signal, the range of broadcasting and the profitability of the broadcasting business, depending on the range used.
Long waves.
The historical heritage of the development of radio broadcasting. But not only. Fluctuations of this frequency range with a wavelength measured in kilometers have a very high diffraction capacity, not only bypassing artificial obstacles and folds of mountainous terrain, but even going beyond the horizon, they can provide reliable broadcasting at very long ranges far beyond the line of sight. The range of broadcasting on long waves is determined by the power of the radio transmitter, the efficiency of the transmitting antenna and the absorbing parameters of the earth's surface. This range is the only one that allows broadcasting in mountainous areas. Due to the physical features of the frequencies of this range, there is little interference on it and the quality of AM broadcasting is quite high.
Broadcasting on the LW band is carried out according to the first category of quality. According to the existing standard for program feed channels, the reproducible frequency band of the first quality category is 50 Hz - 10 kHz. However, the frequency grid in this range has a step of 9 kHz, so that in order not to get into the adjacent frequency channel, the spectrum of the modulating signal is limited at the level of 8 kilohertz on the transmitting side. This determines the real quality of the signal of the first category.
The dimensions of the antenna economy, commensurate with the wavelength and the area required for the organization of LW transmitting radio centers, do not allow placing such objects within the city. And the required power of radio transmitters for reliable broadcasting over long distances (100 - 1500 kW) and the low efficiency of the implemented antennas lead to the fact that at a distance of several kilometers from long-wave radio centers, a long stay of people is highly undesirable. The presence of settlements at a distance of less than 10 - 15 kilometers from a long-wave transmitting radio center is generally unacceptable. The costs of building Far East radio centers and maintaining them in working order are so high that they cannot be paid off by commercial broadcasting. Far East radio broadcasting is planned and costly and can only be financed from some budgets, performing certain social tasks.
medium waves.
They have sufficient diffraction to provide reliable (shadowless) reception in moderately rugged terrain, and in the conditions of reinforced concrete high-rise urban development. In mountainous conditions, they form significant shadow zones, especially in their short-wavelength part. At night, they can propagate over very long distances due to reflection in the ionosphere. During the day they are only suitable for local broadcasting. Due to the spectral specifics of industrial interference, the sound quality in the medium wave range in urban environments is low and can only satisfy conversational radio stations. In rural areas, the sound quality of medium-wave radio stations is quite suitable for listening to music programs in the first category of quality and is limited only by atmospheric interference - in summer, with lightning discharges, reception is difficult. The propagation range of a direct wave in the daytime (excluding ionospheric reflection) depends on the type of antenna used, polarization, transmitter power and, on average, is two to three times higher than the line-of-sight range, mainly due to the low level of interference far from large cities. At night, there is a weakening of the audibility of relatively close radio stations located within a radius of 100 - 200 km, and an increase in distant radio stations - 600 - 1500 km. For radio stations that are in the line of sight from the listener (up to 50 km), there is no weakening of reception. On winter nights on the medium wave range, long-range radio stations can be received with very good quality.
The use of this property of medium-wave radio waves made it possible in the United States to create a network of high-quality AM broadcasting during the daytime, minimizing interference from radio stations located in other time zones and operating on the same or close frequencies and using the frequency resource most densely. These radio stations are called "light time radio stations". With the sunrise in a given area and, accordingly, with the disappearance of the conditions of ionospheric propagation, the radio station can operate with a power of several units or tens of kilowatts, providing high-quality broadcasting at a distance of 150 - 200 km. With the sunset, and the advent of the ability to create radio interference with its radiation far beyond the direct broadcasting zone, the radio station reduces the radiation power to hundreds, sometimes tens of watts, providing a radio broadcasting zone only within its own settlement. From a commercial point of view, this is justified, since the most effective advertising time is during the day, and in the evening and at night it sometimes makes sense to turn off the radio transmitter altogether.
Antenna systems of the medium wave range can be made relatively compact for placement within the city, which does not have high-rise reinforced concrete buildings. But still, it is desirable to take out the radio centers of this range outside the city limits. In the medium wave range, the use of such high powers of radio transmitters is not required, as in the long wave range. With properly designed and built antenna systems, 5 to 15 kilowatts of power is enough to provide cost-effective quality radio broadcasting to a large industrial region or several nearby cities, totaling more than one million inhabitants. With a smaller population in the broadcasting area of a medium-wave radio station, it is difficult to talk about its profitability. Still, the costs of maintaining radio centers in this range are quite high.
Short waves with lengths from 75 to 49 meters.
They have a pronounced nocturnal character of long-distance distribution. They are used mainly for foreign broadcasting to regions as far as possible from the transmitter. In the daytime, the level of industrial interference in this part of the frequency spectrum is so high that any high-quality broadcasting is impossible. The specifics of use comes from their properties: ideological propaganda, broadcasting to compatriots in other countries. The goals are mostly political at the interstate level and can hardly be used for commercial broadcasting.
Short waves of subbands 41, 31, 25, 19 meters.
Relatively free from industrial interference (the higher the frequency, the less industrial interference). Tends to be more diurnal with increasing frequency. Allows you to create round-the-clock high-quality foreign broadcasting, when the radio station, depending on the time of day, according to a schedule known to listeners in advance, changes the frequency of broadcasting, switching to higher-frequency sub-bands during the day and falling to lower-frequency ones at night.
Short waves subbands 16, 13 and 11 meters.
Typical daily ranges. In the reception area, distant stations are audible from the illuminated area of the earth's surface. There are practically no industrial and atmospheric interferences on these ranges. But the presence of a large number of simultaneously audible radio stations on the air during commercial (daytime) time leads to a kind of "air porridge", where it is very difficult to make out who and what is broadcasting. As a rule, the strongest wins - who has the most powerful radio transmitter and the best antennas.
Using the specifics of the propagation of radio waves in these ranges, it is possible to create in Russia a network of local broadcasting radio stations, the so-called "stations of the dark time." With the onset of darkness, the radio station increases the power of its signal to several kilowatts, works like this all night, at dawn, the power drops to tens of watts. In this case, daytime "ethereal porridge" will not form, and in the evenings, especially long winter ones, it will be possible to listen to local radio stations with higher quality than on long and medium waves. Effective antenna systems of these ranges are quite compact, unpretentious, cheap to operate and take up little space. As radio transmitters, military radio transmitters of the main communication, modified for broadcasting purposes, could be used. This would make it possible to use the now idle defense plants for peaceful purposes and for the benefit of Russian radio broadcasting. I believe that "evening home radio programs" would be a success among the listeners of our country. Here is the technical proposal. It's up to the Ministry of Communications and the MPTR. Defense plants, in the presence of relevant decisions of the ministries, will not keep you waiting. Everyone needs orders, and this project can stir up the stagnant regional economy. By the way, on these ranges one could successfully use synchronous radio reception, and on the transmitting side single-sideband modulation with a partially suppressed carrier frequency. Such a solution would significantly increase the profitability of radio companies by reducing costs on the transmitting side. Here you have a new niche for radio receiver manufacturers and a new frequency resource for broadcasters.
Russian VHF band.
The quality of broadcasting is of the highest category. Band of reproducible frequencies from 30 Hz to 15 kHz. Stereo broadcast. Small antennas. Possibility to form any desired radiation pattern. The profitability of broadcasting allows you to create a radio company with a short payback period and relatively low initial costs. One problem. Russian factories are not able to fill the market with competitive VHF radios. Those that are available to the population, with natural wear and tear, gradually reduce the effectiveness of VHF broadcasting. It's a pity. A good range, highly profitable, historically familiar to the Russian listener ... Well, MPTR would have been taken together with the Ministry of Communications and commercial radio stations, they would have secured the acquisition of a license from SONY for the excellent tuner ST215, which supports both stereo broadcasting standards and is already outdated by Japanese standards, they would have done on its basis all-wave radios, flood the market with them... or give SONY favorable trade treatment, let them work, but we will raise a wonderful range. How long can you sit like a "dog in the manger", do nothing yourself to develop your own economy and not give others? It may be that my proposal has not been fully developed from a national point of view, but it is always easier to criticize, evaluate and look for shortcomings than to propose or create something. I would like the ministries to take a more constructive position on this issue, leading in practice to concrete results.
By the way. At the end of 1998, the Moscow marketing firm "Postmarket" conducted a study and determined the parameters of the Russian radio receiver of mass demand. Then, with the help of the radio station "Echo of Moscow" a development competition was held and in April 1999 the winner was determined. There is a working layout, it's up to R&D and implementation. Alas, so far not a single plant has expressed a desire to take up its production. Everyone is waiting for funding. In Russia, it can be expected for centuries. What, our businessmen have transferred? Doesn't anyone want to make money off of this? And we do not need any SONY (yes, dear colleagues will forgive me).
The coordinates of this company can be obtained by contacting me through the editorial office of the magazine "Sound engineer" or via e-mail:
But back to the VHF band again. Historically, in the design of both operating stationary radio receivers and in the development of transmitting antenna systems in this range, horizontal polarization of radiation was used. Unfortunately, not all broadcasters know this. When working out new frequencies in this range, it is necessary to use horizontal polarization and, accordingly, transmitting antenna systems must be with horizontal polarization. This must be taken into account when creating new radio companies.
Western VHF band (FM band).
The quality of broadcasting is of the highest category, stereo, but it is actually better than in the VHF band due to the fact that Western technology is used for receiving and transmitting in this band. As the saying goes:
- What is the difference between "Mercedes" and "Volga"?
- "Mercedes" is made as it should be, and "Volga" is made as it happened.
The same is true in broadcasting. The quality standards are the same, but the difference, nevertheless, is noticeable even by ear. Due to this difference, as well as the saturated market of Western radios and the complete absence of competition from Russian manufacturers, the fleet of radios and, accordingly, the number of potential FM listeners in Russia is constantly growing. Naturally, the profitability of radio companies broadcasting on this band is also growing. And one more factor, not decisive, but very significant. Western cars arriving in Russia are equipped with radios with this range. And this means that people who have enough money to buy a foreign car will listen to radio stations of this particular range. And, therefore, advertising activities for richer social groups will allow the radio company to earn more.
What is usually called the FM band in Russia (87.5 - 108 MHz) is actually two broadcast bands 87.5 - 100 MHz and 100 - 108 MHz. This division is laid down in the Radio Regulations - an international document that prescribes the use of the entire radio frequency spectrum for one purpose or another. In accordance with this document, and based on the Russian internal frequency allocation, the lower part of the FM band was used for television broadcasting. The fourth and fifth television channels of the Russian frequency grid completely cover all frequencies up to 100 MHz. This fact limits the further development of high-quality radio broadcasting. Nevertheless, using the specifics of the spectrum of the terrestrial television signal, under the auspices of the Ministry of Communications and the Federal Service of Russia for Television and Radio Broadcasting, an experiment was conducted in Moscow, St. . The experiment was financed by private commercial broadcasters under the guarantees of the FSTR and the Ministry of Communications of allocation of frequencies in the lower part of the FM band. The experiment lasted about two years and showed the practical possibility of joint operation of terrestrial broadcasting stations and cable television, using the 4th and 5th television channels in the program distribution path.
In the FM band, it is customary to use vertical polarization. This must be taken into account when developing new frequencies and when purchasing antenna systems. Antenna systems of the FM band are even more compact compared to the VHF band, their technology is debugged in the west and the cost, even taking into account delivery and customs, is quite acceptable for the consumer.
When choosing an antenna, it must be taken into account that a 1 kilowatt transmitter operating on a conventional half-wave vibrator will be heard in the same way as a 100 watt transmitter operating on an antenna system with a gain of 10 dB. Only now you will pay the radio center for the operation of a kilowatt transmitter almost 10 times more than for a 100-watt one. Naturally, a kilowatt transmitter operating on a 10 dB gain antenna will be perceived as a 10 kilowatt transmitter operating on a simple antenna.
Most broadcasters know this, but it's still not uncommon for radio executives to find antenna selection a technical issue unworthy of their attention. It's a pity. This is money and money is not small. The type of antenna used directly affects the profitability of the radio company. Remember that you can reduce the operating costs of the transmitter by the amount of gain your antenna provides, and you only pay for it once.
The height of the antenna installation determines the broadcasting range. In the case of VHF and FM bands, this is the only parameter that affects the size of the broadcast area. On flat terrain, the radius of the zone of confident broadcasting coincides with the line-of-sight range and its value can be calculated by the formula: L = (2HR + H 2) 1/2, where H is the height of the transmitting antenna above the earth's surface, R is the radius of the Earth, which is equal to 6373000 m. Here are some values of the radius of the confident broadcasting zone, depending on the height of the transmitting antenna (assuming that the receiving antenna or the radio itself is on the first floor of a building or in a car):
| H (m) | 15 | 20 | 30 | 40 | 50 | 75 | 100 | 125 | 150 | 175 | 200 | 250 | 300 | 350 | 400 | 500 |
| L (Km) | 18 | 21 | 24 | 27 | 30 | 35 | 40 | 45 | 49 | 52 | 55 | 60 | 67 | 72 | 76 | 85 |
The higher we set the antenna, the farther we will be heard. Take a map, draw a circle on it, the radius of which in kilometers corresponds to the height of your mast (see the table) and see in which nearby settlements you will be heard. This is your potential audience in the zone of confident broadcasting. In reality, with a decrease in quality, your signal can be received at long distances, by about 10 - 15%.
We have considered ether frequency resources. But the opportunities to broadcast and convey your radio program to the listener are much wider. Broadcasters who are interested in organizing radio companies in cities with an already spent air frequency resource or who want to increase the intensity of their broadcasting, I invite you to read the article by Andrey Vorontsov "
What is it and what does it mean? Term FM appeared with the advent of the mass market
various receivers accepting the range VHF 87.5 - 108 MHz.
But a little history...
Broadcast permission in the western section VHF range led to a surge in the number
private radio stations. In the USSR, broadcasting took place in the 65.9 - 74 MHz section of the frequency
modulation World Cup. Now in this segment you can still hear two or three radio stations.
In principle, there is not much difference where and what type of radiation to use. So far they go
debate over redistribution of this site to other radio services.
Now let's look at the term itself. VHF. The abbreviation stands for ultra short waves.
Since ancient times, it has been believed that VHF band starts above 30 and up to 300 megahertz.
There are ultra long waves ADD, long waves DV, medium waves SW, short waves HF.
Such a distribution of radio waves was obtained due to their propagation properties in the Earth's atmosphere.
If long waves go around the radius of the earth, then ultrashort waves propagate in line of sight
with numerous reflections from obstacles. VHF radio waves are also used for communication
with spacecraft, since they pass through the atmosphere of space without hindrance.
Short waves have their own unique character. They are reflected from the upper layers of the ionized
atmosphere and return to us.
So the radio wave bands:
SDV 3 - 30 Kilohertz. - Super long waves
DV 30 - 300 Koh. - Long oxen
SV 300 Kilohertz. - 3 megahertz. - Medium waves
HF 3 - 30 Megahertz. - Short waves
VHF 30-300 Megahertz. - Ultra short waves
UHF 300 - 3000 Megahertz - Decimeter waves
But that's just part of the whole spectrum.
Basically, the population of the country now uses the services of broadcasting radio stations on VHF.
Pro HF and SW many have not only forgotten, they do not even suspect. Too bad you heard it before
mostly medium and short waves. The middle ones were broadcast by state
companies, there were news feeds, music, entertaining shows for the adult population,
youth and children. On short waves they listened to Western radio - voices from there.
The VHF band currently used for broadcasting is 87.5 - 108 MHz. also popularly called
FM band, although neither in the international classification, nor in the patronymic such
there is virtually no distribution. The obvious analogy from the past is that
as radio receivers were called in the 60s - 80s - Transistors. It happens for the most part from
ignorance or unwillingness to know something more. Well the transistor and the transistor though it's only
radio component of this very radio receiver.
By the way, Japan has its own national characteristics. Broadcasting in the band
VHF occurs in the area 78 - 88 megahertz also by frequency modulation. This does not allow
to receive their radio stations on our modern receivers, since not all radio receivers
devices have a continuous range of 65.9 - 108 MHz. Only in some Chinese models
provided such a possibility.
FM(FM) Frequency Modulation translated from English - Frequency Modulation - World Cup.
Actually, the population likes the combination of FM because of the sonority, of course, it cannot be compared with World Cup.
Although this name FM band completely incorrect from the point of view of professionals and
radio amateurs.
Because the FM it's just modulation, people who say that are incompetent in these
questions. With this modulation, the frequency of the carrier signal changes in time with
modulating, influencing sound frequency signal - speech, music.
It's also wrong to name ranges. HF and SW ranges AM.
In almost all of the above ranges, radio stations also work with other
types of radiation - modulations.
Here is just a small list of the types of modulation used by radio amateurs:
SSB, AM, FM, CW, BPSK, QPSK, FSK, RTTY, Packet, Pactor, Amtor, MFSK, Throb, MT63, Hellschreiber,
FAX, SSTV, RTTYM, OLIVIA, Contestia and many more.
As you can see now, there are a lot of types of modulations, and now digital types are most common.
radiation. For example, in cellular communication, its original type of modulation is used,
allows you to conduct a conversation without interference and noise of the air. The digital type of modulation allows
encrypt the contents of the conversation and it will not be available to unauthorized persons.
There is a separate conversation about state and military services, here we are only talking about
on civil, broadcasting and amateur services. (See Law of the Russian Federation on Communications)
When you turn on the radio, you hear music and a voice that is broadcast from miles away.
What are radio waves?
AM and FM radio broadcasts are transmitted over the air via radio waves, which are part of a wide spectrum of electromagnetic waves that include visible light, X-rays, gamma rays, and others.
Electromagnetic waves around us at different frequencies. Radio waves are similar to light waves, but our eyes do not perceive frequencies.
Electromagnetic waves are generated by alternating current (AC), the electrical power used to run every device in our homes from washing machines to televisions. Alternating current is 220 volts at 50 Hz, which means that the current alternates or reverses direction in the wire 50 times per second. For example, the US uses 60 Hz as the standard. Both 50 and 60 Hz are relatively low frequencies, but even 60 Hz AC generates some level of electromagnetic radiation, meaning that some of the electricity leaves the wire and is transferred into the air. The higher the frequency, the more electricity comes out of the wire.
Modulation must occur in order to turn into useful signals that convey information (music or voice), which is the basis for AM and FM radio signals. In fact, AM stands for amplitude modulation and FM stands for frequency modulation.
Another word for modulation is change. Electromagnetic radiation must be modulated or modified for use as a radio transmission. Without modulation, no information is transmitted in the radio signal.
AM broadcasts
AM radio uses amplitude modulation and is the simplest form of radio broadcasting. To understand amplitude modulation, consider a stationary signal transmitting at 1000 kHz in the AM band. The amplitude of the DC signal does not change or modulate, so there is no useful information. A steady signal only generates noise until it is modulated by voice or music.
AM radio suffers from more noise and interference than FM, especially during thunderstorms. The electricity generated by the lightning creates the noise peaks received by the AM tuner. AM radio also has a very limited audio range, from 200 Hz to 5 kHz, which limits its usefulness in radio.
FM broadcasting
FM radio uses frequency modulation, which changes or modulates the frequency of a signal while maintaining a constant amplitude. When the frequency is modulated, the music or conversation is transmitted over the carrier frequency.
FM radio operates from 87.5 MHz to 108.0 MHz, a much higher frequency range than AM radio.
The distance range for FM transmissions is more limited than AM, typically less than 160 kilometers, but better suited for music as FM has a frequency range of 30 Hz to 15 kHz. FM broadcasts are also usually in stereo, although a few AM stations also broadcast in stereo.
Although FM signals can be subject to lightning noise, they use a limiter function that cuts out noise peaks to produce a relatively noise-free signal.
