AM and FM Radio As Fast As Possible 

1:43 What's so cool about this, is that when I play my electrical guitar with headphones near my room windows. I pick up a radio station . at first it was scary I thought I hear voices

AM follows the curvature of the earth , well that’s a slap of reality to the flat earthers

FYI: Analog signals aren't "decoded". They are *demodulated*.

Would you like AMMMMMM or FMMMM?!

Gaze upon me and know me, for I am among the rarest human beings on earth. I have a full-time job on AM radio. Full....time.....job...........on AM radio.

Put into consideration on how during WWII when 700 AM WLW (Cincinnati, Ohio) was broadcasting on an outstanding 500 KW of power, at which the entire world could hear the local news as well as keep the troops updated on the wartime news to the point that Hitler himself called the station a nuisance. Fortunately for anyone who would care enough, there's a video on here where a guy walks around the station and shows the massive retired all-tube transmitter, water cooling system, transmission antenna, and power transformers for the old 500 KW setup.

1:00 The sound wave is not added to the carrier wave, it gets *modulated* with the carrier wave. By adding it you would emit your sound wave throughout the entire spectrum, causing heavy interference with every other radio station broadcasting.

My dad taught me how to make an AM radio using simple things found around outside. It's good for emergency cases when all other high-tech communication goes AWOL.

HAM and Shortwave as fast as possible! VHF and UHF as fast as possible! NTSC and PAL as fast as possible!

Hey man, look at me rockin' out, I'm on the radiooo!

If you had posted this a few weeks ago, I would've passed my Physics exam! 😂😂

> death metal > shows Slipknot's Mick Thomson

Yes, Justin Bieber's "Greatest who put that shit in my script" is indeed an amazing album.

Great explanation, makes it look much simpler than what i thought it was. Please also do a dynamic vs basic disks as fast as possible!

Wow I literally asked myself this question about the difference between AM and FM a day after this video was released.

I can't believe the perfect timing of this. I have my physics exams and AM and FM are part of the syllabus. Thanks for this, Linus. :P

lol. 99.5 FM is actually my favorite radio station where I'm from.

Nicely explained, Linus. Though your explanation on AM vs FM when it comes to skywaves vs ground waves is easily misunderstood. Using the ionosphere to reflect radiosignals is done at longer wavelengths/lower frequencies yes, but regardless of the modulation scheme.

"Death metal" - picture of Mick from Slipknot

Wow I am very impressed by how good the complexities of radio modulation were described by using very basic analogies. The "transformer" used in FM may not be the right word (at all) but that can be forgiven. As an engineering student I say well done!!!

Here in the Philippines, FM is for music, and AM is for news! XD

>death metal. >slipknot image

Trust me when I say that while this is a good high level overview... the actual math behind AM and FM can be a bit mind boggling. Learning digital modulation techniques now and to start we covered AM/FM. Trying to find the frequency spectrum of an FM signal of a certain data signal and carrier frequency is a pain in the butt. The practical solutions that we learned still only estimate it (carson's rule, bessel functions...etc). Additionally, one might be interested in knowing that FM itself is only a type of angle modulation, one can also instantaneously vary the phase of a carrier signal to represent data (PM), the result looking very similar to FM but tracking different data signal properties.

Nice video! I'm the Chief Engineer/Operator for my college's FM radio station and this was a nice overview of the technology.

Great video. Good job!

Radio trivia note: The old (analog) NTSC television signal used both modulation types: AM carrying the video portion, FM carrying the audio!

Wow, thanks for covering this topic! Some relevant tech here! Learning about radio and sounds, for me, was the way I started learning about electronics. Wireless sounds are fun.

Another note (years later): at night there are actually less ions in our atmosphere. The reason AM goes further at night is less interference from the sun which, during the day, easily overpowers our AM emitters

Someone once told me that Radio was sound waves....I cried and laughed on the inside at the same time.

You can transmit and AM or an FM signal on basically any frequency. Broadcast bands have been established that places commercial AM broadcast on lower frequencies (535kHz to 1700 kHz) and places commercial FM broadcast on a higher frequency band (87.5 Mhz to 108 Mhz). With the right equipment you could easily transmit an AM signal inside of the commercial FM broadcast band (87.5 Mhz to 108 Mhz). I have a transceiver at home that allows me to transmit AM at 144Mhz or FM at 28Mhz. AM and FM are modes, bands and frequencies are different.

If I put on the radio there's only 2 things I hear: pop music and commercials. I hate both with a passion.

I miss having FM in my android phone. My first one back in 2010 was a Droid X and had FM radio!

Why don't we just reLAAx, we'll turn on the raADIOoo? Would you like AM, or *FFFFMMMMMMMMMMM?*

In my Norway we don't have AM stations anymore and the FM stations is going to go down in 2017, so we are switching to something called DAB and DAB+. Is that happening to anyone Else?

Also, FM is actually a subcategory under something called Angle Modulation. Angle Modulation consists of Phase Modulation (PM) and Frequency Modulation (FM). This is because in application they are varying the angle in a cosine function. Thus the name: Angle Modulation. FM actually changes the frequency, but when you add an angle in the cosine function, we call that the phase modulation, and pretty much just shifts a signal left and right (hence the name Phase Modulation).

The benefits of radio are simple: The infrastructure already exists and receivers are absolutely available at any price range, from old to modern. Even a radio from the 50s and 60s can still be used. Receiving doesn't cost you anything and nobody can trace you back, unlike webradio streams. Plus radios usually run on low power and have a long breath.They can be powered by all sorts of energy. Some radios even run on a kinetic energy dynamo that is powered by a spring movement and don't require any batteries at all. You can even build your own custom radio the way you want with fairly cheap off the shelf components. All that matters is what type of style you prefer. And another benefit of analog radio is that even if the signal quality is weak, you can STILL hear the station through the noise. If the signal of a digital transmission is too weak you get nothing at all or just eardrum shredding glitchy noises. Analog radio is basically THE BEST medium (still) to reach the most people around the world.

Whenever I turn on AM radio it feels like there is gonna be an announcer saying 3 nuclear bombs has detonated in 3 major cities

One of the rare , easy to understnd explanation of AM FM ! tx

WELL, I have to watch this for school... i love linus

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I fixed an old radio for a friend but i could only get foreign stations. I remember a Chinese one and a Spanish one and if memory serves me right a Russian one too. This was from Ireland and the radio was in a place FM radio would have trouble picking up a local station, So if somebody can explain id appreciate it :)

This seriously helped me figure out how radios work and how the Emergency Alert System (and the Emergency Broadcast System before it, and the CONELRAD/CONtainment of ELectromagnetic RADiation system before it) works and how you actually hear the annoying tones that tell you to 'Listen up, bonehead, because somethin' bad's going down soon or already is.' Thank you, Linus, for this explanation and your later one on the EAS, despite my knowledge of the latter.

Misleading explanation of AM. It's a common misunderstanding, but AM doesn't tune to a single frequency. It can't be that way, since a single frequency alone carries no information. When you modulate the carrier, you introduce the frequency components from the modulator which are in the resultant AM signal. These are known as the sidebands, which are mirrored around the carrier. When you're tuning to an AM channel's frequency, you're tuning into the entire band allotted to each channel. Standard AM channels have a bandwidth of 10kHz, which is good enough for voice. This is why radio channels are never adjacent, you need the entire bandwidth for the transmission as well as a buffer area between channels to minimize interference. It's impossible in the real world to tune to a single frequency, since no perfect filters exist. That's also what the resonance circuitry is acting as, a filter. If you were able to just tune in to the frequency of the carrier, that's all you would receive, the carrier. Which carries no information by itself. All the information is in the sideband.

Thumbs up for the picture of Mick Thomson. That guy is like my Kobe.

all i know is AM sounds fuzzy

Learned all of this years ago at Avionics School in the Coast Guard, and this guy does a very good job explaining things spot on and very succinctly. I'd like to see him explain, in an equally efficiently manner, the math behind finding the voltage drop on one resistor on a circuit board. That would be interesting. :)

AM and FM have nothing to do with wavelength... they are just modulation types. FM broadcast band is typically 88-108 Mhz while AM broadcast is 540 Khz to 1700 Khz in the US. This is often called Medium frequency band. Medium frequency can bounce off the ionosphere at night. FM broadcast is in the VHF band and is typically line of sight. There is cases where you can here it for long distances. Tropospheric ducting and bouncing off the ionosphere called e-skip. These effects however are very rare and uncommon.

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Now from the perspective of someone who has an amateur extra license I'll tell you more about FM. It experiences one thing you missed called Tropospheric ducting allowing a 5 watt transmitter to reach 200-300 miles out. Has to do with what are called temperature inversions.

3:35 That wave's AM, so that's correct 3:40 That wave is still AM dude (Its not FM) lol

It's pretty amazing to pick up some of those far off AM stations at night. I remember driving through Nevada and picking up KCBS loooong before I got close to the border.

I thought AM was morning radio and FM was afternoon radio .-.

Thanks, for the lesson, you explained better than most.

"WOULD YOU LIKE AM OR FM", the first thing I thought of when I saw this video, now if you will excuse me, I need to fix my car, I think the prndl is broken.

There are fewer free electrons at night. (The solar radiation frees electrons). Lower frequencies in the AM band are reflected a night because the free electrons that block the reflection re-join the atoms. However frequencies between the AM band and FM band are referred day and night.

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Thanks for the content! i just started my hobby as a radio listener and archive 6 days ago, and this realy helped me understand what AM and FM is. Thanks comrade

Wish you included DAB radio in this video :(

Very useful video but keep in mind that both, the AM and the FM are analog driven and as mentioned in the comments - the right word is rather demodulated than decoded. :)

Radio, the original streaming service 😎🍹

wow thats sweet. My father use to tell me he could hear radio stations from Florida back in the 60s (all the way from northern Jamaica), didnt know AM radio had that property

Remember: sun up frequency up, sun down frequency down.

That's what this generation of the Digital age needs to do. They need to learn how to Appreciate what we DO have just in case if something DOES happen to the Internet that they depend on SO much. Don't go discarding OLD technology just because we live in the Digital Age. That Old Technology COULD save your life one day. Put it in another way, our way of life may revolve around Modern Technology but the Forces of Nature out there doesn't such as the Storms that we see from Mid Spring to Mid Winter Tornadoes, Hurricanes, Earthquakes, Floods and Blizzards. The Cloud-to-Ground Lightning, Gusty (+60 mph) Winds, Moving Ground, The Rain and the Ice that falls from the sky can knock out or Potentially destroy the electricity on the Utility poles that y'all depend on for your Wi-Fi needs. Can't Run Wi-Fi and get the Information you need without electricity. They can throw you into that situation. Where you're left with an old battery-operated AM/FM radio as your only resource for information. Now your Smartphone may have a chance of getting information without Wi-Fi through the Cell Phone Tower that is if you don't mind using data for it or if the Tower itself is not in the path of that particular storm where it can be destroyed. If your Smartphone fails on you during that situation your gonna need that Old Radio to let you Know of what's going on.

What would it take to receive permission to show this video to communications students in a community college classroom (as a basic introduction to transmitters and receivers)?

Thanks for the recap, needed this for an exam

One thing I found weird with fms is if you’re listening to 99.5 fm (for example), and you switch to 99.4 or 99.6 you can still hear the same station as 99.5 although you can hear some static. I live in India and here we have more fm stations compared to am. I listened to both fm and am and I find that in am volume goes up and down and in fm I can hear static sometimes.

Answered all question I had concerning frequency modulation I was afraid to as, explained in a fashion even I would understand. Thank you, Linus!

FM Radio, why is it popular? Free, sounds great, local

O0oooh! I thought AM was meant to be listened in the morning and FM Friday to Monday. Thanks, dude!

I find analog technology, although technically inferior, way more fascinating than digital technology. It seems so much more difficult to get right that the fact that it can end up sounding or looking as good as digital is mind blowing.

Merci beaucoup Professeur. Je trouve cette vidéo trés utile...

“A.m. is fine for talk radio” tell that to my boss lol

Slight correction, whether a signal propagates via the ionosphere has nothing to do with the signal's modulation, but entirely to do with the frequency. Signals below 30MHz tend to propagate via the ionosphere much more readily than signals above 30MHz. Since the AM broadcast band is from roughly 0.5MHz to 1.6MHz, and the FM broadcast band is 87.5MHz to 108MHz, the AM band bounces off the ionosphere much more readily. Amateur radio operators use FM on the upper part of the 10m band at about 29MHz, and it skips quite well.

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i'm a bit disappointed that you did not mention DAB radio. because in Norway everyone MUST change to DAB radio by 2017 and all FM radio stations are being shut down. I know it uses satellites in space and stuff. Would love to know more about that

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Pretty good but you strayed a bit when describing the distance part (at the end) Emphasis was needed to explain that its not the MODE (ie AM-FM) which increases distance but the commonly used frequencies . I would have used the term "AM Broadcast band" and FM Broadcast band . Signal to noise ratio would explain range issues also but that wouldn't be making it simple .

I would listen to radio, but I don't have a car yet...

You guys have come a LONGGGGG way from 2016... Sheesh. Where is Anthony when you need him?

+linustechtips IT IS NOT as simple as a couple of wires!!!! Tuner circuits are beautiful LCR circuits. When you turn a knob, you rotate plates which change the common area between parallel plates, thus changing the capacitance(C). This in-turn changes the resonant frequency of the circuit(because resonant frequency omega=1/root(LC).

Thanks for the flashbacks to my signals processing course linus. I really needed a good dose of not knowing what is going on.

Hey kiddo, you're not old. Your first computer was a AthlonFX.

The way I'm interpreting his video is that when you tune your radio receiver to a certain station, your tuning to the carrier wave frequency. The carrier wave is just that , a "carrier". The stuff you want to listen to (also a analog signal) is superimposed with the carrier wave, then off they go into the wild blue yonder. Your radio receiver's antenna will pick up the signal, as you are tuned to the carrier frequency (if I' m interpreting his video correctly) .

why are radio station frequencies end in an odd number? its always 98.9 or 104.5 but never 100.6 or 99.8?

The distance a signal travels (given all other things are equal) is related to its frequency - a FM signal will travel as far as an AM one at the same frequency.

my phone's loaded with music streaming apps but a lot of the time...I'm just listening to a local fm radio station on the next radio app that unlocks the fm chip in the phone :I

I love to dx AM radio at night. The furthest station I've picked up was AM 870, WWL out of New Orleans, which traveled almost 1900 miles. AM 1040 WHO is a common station here too, which is roughly 1500 miles away. DXing is so fun. Its the thrill of finding that long distant radio station, way, way out their. You need a good AM radio though, with a good AM antenna. I never have tried, but the "graveyard" frequency's are a jumbled mess, but there are people who try ( and successfully catch ) distant radio stations in the rumbling audio.

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It's interesting to know that FM radio was invented precisely to solve the static issue with AM. But the company owner was NOT happy at all. What he wanted was better AM radio, not a completely new radio system. That's why it took decades for FM radio to get onto the market. Nowadays, AM is basically dead and it's frequencies are being reassigned to other services like cellular phone networks and such.

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0:46 Linus, don't lie, you are a Top 100s lover!

what about DAB?

love it! I was just thinking of fm and am on my sleepy drive to work this morning for some reason. perfect timing and great description

well, too bad AM and FM radio will be gone within a few years. well, at least here in the Netherlands. (fun for those who do not have digital radio in their car)

One time my radio pick up unknown language but there music was catchy. You're video explained a lot what happened to my radio. My radio never pick up unknown radio station again.

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As an RF Engineer.. Good job simplifying it down.

Bassiclly Am and Fm to me is, Fm songs, Am static.

I had to learn all of this in college. I found it to be super interesting while my classmates were bored to tears to have to learn about it.

Slipknot death metal? C'mon guys!