During my childhood, I built two spark gap transmitters out of two car ignition coils, two motorcycle batteries, a homemade telegraphy key, a spark plug, a simple LC tank circuit and a very long piece of wire to be the antenna. The receivers were just AM receivers tuned to the top of the scale. I gave one of the abominations to a cousin I had living about two miles away. I kept the other one. We both tuned our AM radios to 1610 AM and started tapping away. We could hear the other operator easily two miles away and we had a cheat sheet to tap out the Morse code letters. Unfortunately, those were the days of analogue television that was received over the air with a TV antenna mounted on the house roof. My cousin and I were not the only ones that could hear each other tapping out or butchered Morse code. We tapped out our messages most of the summer. At the end we did not even use the chest sheets. Then one day my father found me tapping away on my spark gap transmitter. I got in major trouble. People all over the neighbourhood were falling victim to my sloppy transmitters on the telephone, television, and radios. After a date with dad's scorn, I had to take my cousins transmitter back. My father made me go get my cousin's transmitter by foot, dismantle it, and carry the heavy, bulky, transmitter parts back and give them to him. It was 90°F so it was not pleasant at all. The two batteries, two coils, excess cable, home made key, and simple tank circuit all weight what felt like about 85 pounds. I guess that was punishment enough. The transmitters was never mentioned again by my parents. I thought they were cool. The neighbourhood did not.

Just so others know, the whip antenna that is extended on top of the portable radio is for FM only, the transmitter he has built is AM and the radio uses a ferrite bar antenna that is located inside the radio. That ferrite bar is very directional.

You always seem to answer something I've been recently thinking about. Just a few days ago I was wondering about radio transmissions, and now here we are with a great video explaining it. Thanks for all the hard work you put into this channel!

Awesome vid. Love the energy, pace, content, and most of all, the thoroughness in explaining and showing your project.

This really does work! I built one this week and it works surprisingly well. The audio quality is pretty good considering it's AM.

Dude u r a rare breed, smart, well presented video and u can draw well! Subscribed!

This is the best explanation of how AM works. I thought I new AM pretty good ,but this shows how you never know everything. I have never seen such a simple way to make a AM transmitter. Using just a Oscillator and a transformer was great.Keep up the excellent videos and thank you.

I think this was a better quality video. You actually took you time explaining and went in-depth on how it worked. It made it so people like me, who don't really know anything about electronics, could really understand. Nice job!

Nicely explained in a really cool way!

I just saw this video, and it's very informative. I just would like to see a list of the things you need to build it, and a list of places where you might find them. I hope later in the future you might revise this video to show how to wire a bluetooth component to it instead of just an auxiliary port, just to give that much more portability. I myself am wanting to make one to use in my classic car without hacking into my dash. Fantastic video though!

Love your videos, I'm actually learning quite a lot from them! Keep it up!

I would really realy appreciate it, when you show us a AM reciever the next time :) Btw this was a really good produced video! Keep on doing this videos I really enjoy those! You have now a new sub :)

Oh ... how I love the things you do ^^ I wanted to build a device similar to that for a school's project but my teacher couldn't really hook me up with any support and I couldn't find good one either. Also, my knowledge about this area of technology was very limited back then. So I just let it pass. And now months later your video rolls in and shows a good and simple way for building a radio transmitter. Sorry for this wall of text but I just wanted to share my exitement when I say that you finally tackled this topic! Anyways, keep up the good work ^^

Without a license the legal limit for AM broadcasting is 100 milliwatts, with a maximum antenna length of about 10 feet (this is highlighted in Part 15 as well).

"its over in that building over there" dude thats your house lol

Pretty amazing video man and its also educational :D Keep up the good work

Wow...I finally understand how this thing works ! 🎉🎊Thank you very much 👍🏻

yasss!! Keystone Science. Yet another great video!

I’ve accidentally ordered a 50mhz oscillator. Now I have to make a 50mhz reciver.

Thanks for making awesome vids!

3:23 Thanks for your uploads. I like them. One small pointer - that was a slip - the "1000 Mhz"...

Sir, the frequency of your speech is about 1 MHZ ! Great Video ! Keep it up.. Love from Singapore...

Great channel. Keep it up!

o nice, i absolutely love you, i just needed this next week, thanks a lot dude.

Very good video. I learned a lot

Great video - given the limitations of the crystal oscillator and the sub harmonics that transmit onto other bands, is there a way of adding in a RF band pass filter and how would you put one in for the desired frequency?

Hey man do you even know that you are a genius?? Keep up the good work ....

1:10 - 4 rounded corners & 1 sharp corner...

Thank you very much for this video!

Cool video! I always wondered, how i could build an Am transmitter by my selfe! Thanks!

good stuff man

great video !! go ahead with such !! we all like it. pls tell me someone : can I use different Crystal value ? if yes, what need to change for this ?

I somehow clicked the notification without it switching to KZfaq app, so I had the sound only on my phone and had no Idea where it came from, when listening closely I heard something along the lines of "this is gonna broadcast on frequencies illegal in your country" and I almost thought I was somehow receiving some secret transmission, but then I found where it came from and it was just you :)

I'm actually planning to use this transmitter to radio control an engine's throttle in an interesting way. My idea is to transmit a variable square wave to a receiver unit on the motor to vary the torque output of a small electric motor that can pull the throttle open and let it close with a spring. It will have a mechanical safety system so the throttle can't open without someone actually on the vehicle.

Cool idea. Even in place of the transformer, you can include a carbon microphone in the power circuit.

very nice and simple.

well done

I love your channel 😀

What is the specification of your transformer? Nice video by the way!

The circuit you shown for a amplifier for the transmitter I would use a negative voltage on the ground for the LM386.

GOOD JOB MAN WHICH YOU THE BEST

Excellent

Superb

Nice Video! 👌🏻

very nice!!!

Great video to start the youngen into electronics.

What pen is that? It looks really cool!

You could refine this with a band pass filter on the input. And a low pass filter on the output. So the signal only is heard on 1Mhz and not on 2,3,4,5 MHz etc. 👍🏻

Double Thumbs up....very informative. Can you make a tutorial for transferring electricity within a house to make the light bulbs wireless specially CFL???? if you have already done please give me the link.... Thanks

Hello! I totally agree with you - AM transmitter is much easy that FM UHF. But if you want to realy translate your own program on long distance - you need a space for the antenna (2 long wires with length = 1/4 wavelength per one wire) and you should adjust the one in resonance. If your transmitter works on 1600kHz - the length of the antenna (dipole) will be quite long - 125meters.

If you want a transmitter for long wave radio there are circuits you can build. Popular Electronics had how to build one. The only problem is you may have wind your own coils. The part needed was sold by Lafayette Electronics which went out of business years ago. My friend went.to the trouble to build the project and it worked as far as in his house but the range was short. So he just abandoned the project. Maybe someone has corrected the out of tune problem. That what popular Electronics call the one section for correcting errors on circuits.

Thank you sir

cool !...... made all kinds of jammer/Xmitter circuits(broadcast TV, AM/FM, vintage cordless house phones & even analog UHF cellular) back in the day......mostly just to F with A-hole neighbors & Guidos blasting disco/rap in their IROC's etc........ was perpetually on the look out for the FCC van / dudes with directional antennas !

For your next video,would you prove this circuit,it transform radio waves,in dc current? I'm a big fan,great job ;)

Thanks for sharing friend! Do you have a video for receive?

If you ever get the chance, can you show how to make a fox hole radio? It's a radio that was used during WW2 and consisted of a blued razor blade and no power source. Keep up the great work!

I want to get a clarity on what factors does the range decide and how can I control it's range .pls make a video on it.

Hey I've asked this on another video but what kind of accent are you speaking with? I've never heard anyone talk like the way you do it's so unique.

What do you think the range would be if you didn't add an antenna? I'm looking to make one for about a 6 foot transmitter so I don't have to buy a new stereo for my car. (it's AM only. real old one.)

do you happen to have more detail about the transformer and how to drive it w/o a cell phone?

5:59 how did you amplify the signal. I am confused as there is only one antenna cable coming out of the transmitter and you had connected two wires. I just would like to ask for an explanation how did you do it.

what is the voltage on the secondary side of the transformer that will kill this system? got a 25W TDA amplifier having its peak output at any frequency 12V....i got an old ferrite core doorbell transformer (quite a powerfull one) and it steps down 220V to 24V---- i did made and "inverter" with the amplifier so you can use a 240-12V transformer hook 12V 50Hz signal which comes from amplifier creates quite powerfull arc...but where is the limit and what is the sweet spot for this design?

A Video about a >big< musical Teslacoil would be great :D

So the antenna is everything when it comes to the range of radio transmitters?

I like the video I LOVE the basics. Yunno one's the one's that makes you think to make it. Not today's world of apps and programs that do everything. DO you have a video on a Foxhole/Crystal Radio? I'd love to see your variables that you use. You explain things fast and well so your easy to learn from.

The FCC allows an antenna up to 9 feet or less and up to 100 mW and you should not cause interference to other local AM stations,. They do recommend the use of a battery, and also a circuit to help eliminate harmonics. The signal should not go over 100 feet, but distance depends where you're located. If you're in a rural area then 1000 feet should be okay.

I wanted to do mechanical or electrical engineering but I didn't score well in high school I got a B, and that was enough to break my dreams. I loved science, I wanted to do all of these things, but now I'm studying accounting.

Is there a crystal oscillator in the range 160-190KHz?

You should list the pens you use in your description. I saw a Pilot Metropolitan and I think.. an OHTO?

If I chance the signal which output from an adruino to audio input, this circuit can operate? I have a project which have to transmit Morse code through AM. So I intend to use adruino to code Morse, then send through your circuit.

Good video. If you like this kind of thing, getting a license to do more is easy. Amateur Radio is licensed in most countries.

how do we make the thing at 5:30 ? where it says ground what does that mean ? the ground of the audio source or the transmitter ? heres where I get into troubles

hey, I really like all of your videos .now I am trying to do a flintstones tesla coil if you can make a tutorial on how to make a flintstones tesla coil it would be soo helpful. please.

Hey plz plz plz tell me if it's possible to modulate Fm using same crystal circuit with transformer or any single transistor , i know single transistor fm transmitter circuit exist but that's not stable like this ! Plz share ? Because i wanna built fix frequency pet or dog tracking device ?

They're selling that DC power supply you have for around $60 to $70 for the 30V 10A version. I wondered what you thought of it? I was hesitant to purchase because of it's low price point, lol. It's branded as Yescom I believe.

Awesome video if you don't mind me asking. The only thing I don't understand is what is the purpose of the transformer? Under normal circumstances I understand how a transformer works and this application I don't get it.

+ keystone science could you use that lightning effect to track thunderstorms? Just an interesting thought

Great quick video. I connected my transformer to my positive rail and my power inuput at top left. I see a strong spike in SDR UNO. No sound from my phone. I do hear my phone if I connect the transformer to my positive rail and the antenna pin but the range is like 3 inches from antenna. Anyone have any thoughts?

Hi! Does the frequency of the oscillator alter the frequency broadcasted? I.e if I use a different 2 MHz oscillator will it broadcast on 2000?

Hi sir, can I ask what is the value of the step up transformer that you used? Hope you would answer my question. Thank you :)

Could you scale this up with larger amp and antenna and get longer range

Hi. Nate . can plzz say where i can get a oscillator chip because i have not got it

Where can I get a good step up transformer like the one in the video I looked and did not find any

How do you set an specific frequency for broadcasting the signal?

Little off topic, but could you maybe make a video about one of your bigger Tesla Coils? You have made some smaller ones, but I would like to see how you made the bigger one.

Can I use a 1:1 ratio transformer?

Could you replace the crystal oscillator with a variable resistor so you could adjust the frequency which is broadcast?

200 feet is the legal requirement unless you use 26 or 27MHZ with no range restrictions as long as signal does not interfere with local radio.

Can someone explain to me how I can use the formula in the video to calculate the right capacitor to use in the receiving circuit. I would appreciate that.

cool

Well Hell you just Ansered a Question of mine that I was looking for about a Year my question is how do you get rid of the ringing?

genial esta muy bueno amigo

Hey does anyone know where i can find this in greece beceuse its dificult to find that oscilator

Thank you. Keep up the great work. I do have a "silly" questions tho..... your dress shirts you wear under you lab coat.... do you put much thought into picking then for the videos?? (Warned you it was a "silly" question. Haha) it's just one of those little things I seem to notice in videos. Lol. Ya, u know I am a bit "wierd ". Take care

@9:33 the audio wave is inverted at the lower envelope compared to the upper envelope.

how do you know what frequency it is transmitting on?

i can't find any ocillator with 3 pins... where can i find them?

Can i use higher frequency osscillator?

Wow AM transmission looks stupidly simple to make!!

Kindly suggest if AM Radio Transmitter KIT is available at a discount of 50℅