When I was in high school, I worked in an engineering lab. One of the engineers sometimes liked to listen to country music. Another engineer didn't want to hear it. He stuck an antenna wire on an RF signal generator, tuned it to the radio station frequency, and slowly turned up the amplitude. This was done stealthily, of course, so the other engineer had no suspicion. The music just faded away.
This is the dream! I've been wanting to build an RF switch (both RX and TX) for YEARS and I couldn't. Even my professors back in my uni days wouldn't help. Yes using RF modules would solve it, easily, but defeats the whole purpose. I want to build it from scratch!
That would be cool, especially in the manhattan style circuit board for good measure lol Come the day of the Internet apocalypse, it could prove to be very handy.
would´ve been cool to build an actual oscillator based on discrete components instead of using an timer IC ;) Back then, there were no ICs inside tube radios 😁
@@brankotdk it was a "rocket radio" from the ealry 60's. It was a crystal radio (the crystal in this case was the earphone itself) which actually works like a diode but can only pass a very low current as far as i know. Radios from the 30's worked similar, but had a amplifier tube and and speaker. And of course no 555 timer IC 🤣
The "easiest" AM transmitter would be to feed both the oscillator and the audio through capacitors, connect the output of both capacitors together, and send it through a common-collector amplifier with no bias voltage on the base. The effect is a carrier signal that changes amplitude based on the audio strength.
The addition of this vowel will certainly minimize the number of possible candidates.... Not widen it 🤣. Just like how adding science to arts does the same thing.
@@jamess1787 what do you mean "minimize candidates"? The more the movement covers, the more interested parties there can be involved. It's not like a person is forced to do anything in particular with a program, it's just about encouraging and fostering learning and skills
@@greatscottlab Hallo, greetings from Venezuela. Thank you very much for your videos they're so cool and helpful! I've been researching a little bit about IC that could function as a replacement for the TA7642 of your AM RX and I found out this two ICs the TA7640 and the TA7641, would you recommend either one of them to be used in place of the TA7642? Thank you very much for your time and help on the matter, I really wish you're having an excellent day! Tschüss! :)
wireless technology is always cool, can't wait when Great Scott will soon build up a remote control circuit with just a basic components locally available without a complex IC. and i always dream about it
I tried to make this one, I used 12v as power supply and I tested t 3m away and when I am touching the output the signal increases and as I don't the signal disappears, why is that so? Can someone explain me?
@@N0Xa880iUL no I don't have any kit I made it by my own using a cardboard roll and wrap wire around it to make inductor and using razor blade and pencil led to make diode and a gang capacitor for tuning
Hi Es wäre vielleicht eine bessere Lösung einen Quarz zu nehmen so dass man einen Sender hat der stabil auf 1MHz oder 6MHz senden kann die Modulation kann man über einen TL494 machen da dieser sehr linear die Pulsweite verändert wenn sich auch das audio Signal verändert die Antennen Anpassung ist auch ein wichtiger Faktor der beste Sender bringt nichts ohne Antenne . Damit die Oberwellen gut unterdrückt werden könnte man einen PI Filter benutzen mit welchem man auch gleichzeitig die Antenne anpassen kann . Wenn man nur den Träger haben möchte ohne Modulation waren es dann bei 12V Versorgungsspannung nur 6V welche die HF Endstufe bekommt und das audio verändert die Spannung zwischen fast 0-12V so bekommt man etwa 100% Modulation das Audio klingt dann deutlich besser :)
In spite of what someone else posted earlier, you can operate an unlicensed AM radio broadcast station in North America by an agreement made between Canada, U.S., and Mexico as follows: Unlicensed broadcasting - 100 mW DC input to final amplifier with a 3-meter maximum length radiator, no license needed, may be measured at edge of campus for school stations.
@@shriniwashasefirst select an empty fm channel for ex you choose 94.5mhz station in reciver press button of remote and with the help of screw driver rotate a black thing you will see in wrapped around coil. You will hear a around 1000hz tone. find in pcb from where around 1000hz tone is generated. From there add audio input or audio can be input in series with battery. Audio can be inputted from mobile phone using aux cable
A 555 is a filthy triangle wave generator, and the signal generator chip can do FM or PSK, still oddly under- and over-engineered solutions, but certainly more informative than using an arduino timer to make AM radio bleeps, or the pi clock to spam FM with square waves.
Actually, hex inverter, eg. UB4069 will be simpler, work better than that and draw less current. Even if Xtall be used as harmonics we can reach up to 300MHz with very clear transmission (AM or FM). Just make sure make a very simple class A amplifier with 2SC9018 transistor For receiver, please don't build bird nest version like this, just attach in PCB with wide ground plane, it will give a huge stability. Greetings from Indonesia 🇲🇨
I bought the xr2206 unit and ran into two problems. In my version, pin one of the IC was grounded so I pulled the chip and bent the pin out so it was no longer grounded. I then tried sending a signal to it using a cassette deck through a one chip mono amp. It worked but was very distorted. I tried a number of things to resolve this but nothing worked. Any ideas? Suspect severe impedance mismatch but can't figure it out.
Actually, running that 555 output into a tank circuit (probably with a buffer amp) to make it resemble a sine wave and modulating the power supply voltage with the audio would work pretty well.
Yes because we are capable of our own networks. Right now Pakistan is limiting people's cell phone coverage to only those who are vaccinated so having such independent Is critical for speech free. It is also off their grid and connection to the Internet of all things.
I'll take a look at this video later, but lemme say thank you so much for brinign back life into such an old topic. Back in school in 2016 i successfully but an AM transmitter only using 2n3904 Transistors (Hartley Oscillator), and i wanted to build the receiver to go along with it, but none of my receivers ever worked. I've tried SO many configurations without "cheating" or using too complext ics, i wanted it to be a receiver using NPN transistors too, but the main issue is idk how to properly measure or deduce why my circuits never worked. Wanna say thanks again, i feel like there's hope for my project again. If yall are interested i can get the schematic of the transimtter that worked at lest. Thanks @GreatScott!
hey i had the same issue, it's real frustrating maybe try this circuit www.talkingelectronics.com/projects/TheTransistorAmplifier/images/Fig71bd.gif you don't need the transformer, just connecting the speaker from 3v to the collector of the last npn transistor works fine. And make sure to put >22uF decoupling capacitor across the supply so there's no unwanted noise. 2n3904 and 2n3906 transistors have worked fine for me. Only problem is that the output sound is really small. Maybe you can replace the speaker with like a low value resistor and then add a class A amp after the last stage. (don't tinker with the other stages, doesn't make the sound louder, i tried yesterday) hope it helps :)
@@Kevin-jz9bg Thank you for the reply! it REALLY means alot to hear that there are others that tinker/deal with this kinda stuff given im a noob. I'll definitely test this. Here is the transimtter i used to build it. Its based on a radio project from a RadioShack 300 projects in 1 kit. I took their morse code transmitter and added my computer speaker input into it. i broke it up into 3 stages because it was easier to draw lol. bubbamachina.files.wordpress.com/2018/04/am-transmitterpng.png?w=666&h=1024
@@bobbysamuels1308 thanks for sharing!! I'll try to build it and let u know how it goes!! For the inductor in the hartley oscillator, can I just take an am inductor from my am radio and tap the center? (it's 55 turns on 1cm * 10cm ferrite rod) I'm a total n00b too but hey "it's super cool, which I think should be the only prerequisite for doing science." - Physics girl U shud check out talkingelectronics.com for a buttload more of projects :) i recommend buying some generals purpose npns and pnps in BULK and just building whatever seems interesting: www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P2.html?ref=driverlayer.com
Interesting. I made an Am transmitter with the 555 a couple years ago. As I remember 600- 700 KHz is about the max you can set up the 555 to oscillate at. Mine did work. It had horrible harmonic issues and was all over the place. I had used an audio transformer to modulate the carrier. Did it work, yep but..... not exactly clean at all and likely not worth the effort to filter....
You need to study for a general class license using them kind of watts. Most amateur radio is home made when one cannot afford to fork out a few thousand dollars for a built unit.
Hallo @GreatScott! , greetings from Venezuela. Thank you very much for your videos they're so cool and helpful! I've been researching a little bit about IC that could function as a replacement for the TA7642 of your AM RX and I found out this two ICs the TA7640 and the TA7641, would you recommend either one of them to be used in place of the TA7642? Thank you very much for your time and help on the matter, I really wish you're having an excellent day! Tschüss! :)
I like simple. I used a 6888 vacuum tube, a tank circuit, and a TTL oscillator, with a triode to drive the screen grid. Works great. I get about 5 watts of RF.
You can't reach 100MHz regular broadcst frequency with 555 but you can easely produce phase modulation with it, that can be demodulated by a FM receiver. If you buy an old army wolky-talky (various models have various bands but in general they start at around 30MHz to around 55MHz-60MHz and small ones (several kilograms that is, sized as a small netbook with 3 times its thikness) are ususaly from around 40MHz to 47MHz) and find 555 variation that can reach 40MHz (both are accessible) you can try it.
Why should one use an integrated circuit, when the same or even better results can be achieved with one or two transistors and a few passive components?
Hey GreatScott, have you also considered trying a circuit like keystoneSience did in his video (th-cam.com/video/O3SuM5Z2S78/w-d-xo.html)? It uses just two components and works also reasonably well
It's actually a FM transmitter, but because of the way AM receivers work, it's a hacky way to do the job. The AM transmitter is looking for a signal at its tuned frequency. As the carrier moves away from that frequency, the receiver sees a reduction in signal strength on a bell curve. So an FM transmitter centered on the same frequency will cause the same reduction in signal strength, by moving away from the tuned frequency instead of by adjusting the carrier strength. So it "works", but it also interferes more with adjacent channels as it encroaches on their band.
Enjoyed video regarding the transmitter build. It's probable that your circuit likely complies with Part 15.209 if you need to keep the radio relatively close to the transmitter. Your video will certainly be of interest to the would-be Part 15 broadcast enthusiast who wants to build their own transmitter before graduating to one of the more costly, high performance Part 15 AM transmitters. Thanks for sharing.
Why do it easy when it can be done more complicated. A TL072 can be used as colpitts Oscillator and OP with variable amplification done by a JFET in the featback. The NF signal goes to the gate of the JFET. The SA602 or SA612 ist a mixer with build in oscillator. Both gives real AM without any detours.
Antenna coil using a coil form made from a business card- use a small piece of hookup wire between the former and the ferrite rod to space it so that it can be moved for tuning. 1 transistor colpitts oscillator + modulation into the base. 1 transistor reciever... into an earpiece using another ferrite rod coil on former with fixed capacitor. maybe a movable tickler feedback winding to cause regeneration
In the U.S. (no idea in other parts of the world, but probably similar) without an F.C.C. class 'C' license (now known as a "technician class"), you can not operate a radio transmitter, A.M. or F.M. with a total broadcast output of greater than 20 watts or a transmission range of greater than 20 miles. This is *only* when using a transmitter whose design and commercial manufacture have been pre-approved by the F.C.C. In the U.S. this is from the regulation congress passed in 1987 that allows you to use your citizens band radio, and radio controlled models and toys without an F.C.C. class 'C' license. An addition was added to that regulation in 1995 to include the unlicensed use of your cell phone (your cell phone is just an F.M. radio transmitter and receiver). A non approved transmitter such as a hobby built unit can not exceed 2 watts total RMS at the antenna, or about a 500 yard broadcast radius unless the actual transmitter part of the circuit is a sealed unit with F.C.C. pre-approval. Whether or not some F.C.C. official is hiding in the woods to catch you broadcasting at 5 watts, I leave to your imagination. As for using a square wave generator (555 timer IC) as a broadcast Carrier Wave, all you need to do is scope the CW signal at the RX antenna to see why it's a crappy idea. You may be "sending" a square wave, but the receiver antenna sees a spikey, bipolar, saw tooth (more like an inverted shark's fin) wave form. This make's it extremely difficult to filter out the overtones and sub harmonics caused by the spikes.
I thoght you were good at electronics Scot. But you always use the 555 timer for all OSCILLATORS pls use other old school or more like I mean arable multivibrator for future projects
Got you beat on stupid easy AM transmitter. I used an LM386 to boost the audio from my 3.5mm into a small audio transformer and into a full can oscillator. You can get them at many frequency's the higher the longer range.
only using FM band is illegal. AM (LW, SW1, SW2) is good and even in poland is allowed only not on 225 khz beacouse there is 1'st poland radio working from 1929
well, it is legal on low power in Australia as long as you are under 3W you should be fine, with HAM stations, 5W with a armature license is fine, just don't be a d*** and start punching it up high. I have a AM transmitter just down the road from me- commercial and I'm able to hear it right to the border of my state... my state is larger than Germany, as they are only using a 2kw transmitter it could possibly even make it to Antarctica by bouncing off atmosphere and water.
I’ve seen fm transmitters for sending audio to car radios for drive ins for about $35. I wanted to buy one to watch movies with my friends but I would love to see if it could be built for cheap using standard components. Maybe a cool diy or buy?
You can get some for much cheaper direct from china on the usual suspects (AliExpress, banggood, gearbest etc...) I've found a Bluetooth to fm transmitter for 2.46€ on AliExpress.
In the 90s i took a gadget made for amplifying ambient sound to earphones and reworked it so audio output from Walkman was amplified and output into several small tv speakers mounted in a box. Essentially the first cordless personal speaker. How could i have made it more powerful?
Hey Scott! Awesome video, but this AM waveform on 3:04 is not the best honestly. I get it, it's hand drawn, but it really got to a mix of AM and FM :) As a tip for the next time, you could've drawn straight vertical lines with pencil to indicate where peaks of carrier are and should be in resulting signal :)
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When I was in high school, I worked in an engineering lab. One of the engineers sometimes liked to listen to country music. Another engineer didn't want to hear it. He stuck an antenna wire on an RF signal generator, tuned it to the radio station frequency, and slowly turned up the amplitude. This was done stealthily, of course, so the other engineer had no suspicion. The music just faded away.
“Honey, why does the country music stop whenever we drive by the engineering annex” XD
Strictly not legal to jam a frequency but its a lab so one cares
haha I would notice something odd's going on that would trigger my need for investigations 😅 unless it jams the whole fm range
@@hadibq It just faded out and back in like atmospheric conditions. This was AM radio, so a strong carrier overwhelmed the detector.
@@lavakumar5944 Exactly and of course, when this is discovered by the first engineer, payback can be a real b****!
Fun fact: this video is not sponsored by JLCPCB.
😆
Uh ok
Faktycznie :D
Nooooooooooooo!
Then u are a regular viewer like me
Will you be posting more videos for the "trying circuits i found on the internet " series?
Yep, there will be more episodes.
Oh yeah, please! 😍
I'm looking forward to it!
@@greatscottlab speaking of wireless communication. Try making a tv transmitter
👍❤❤
Getting boxes to talk to boxes. Coolest stuff on earth
Your unmodulated AM signal should only be 1/2 of max amplitude, or 1/4 of max power. Much better sound quality !
Thanks for the tip :-)
Thank you Pepe the Frog
why this man is posting his link in every comment of great scott किन हह
@@projectnepal8482 why this man is posting in every comment किनभने
Which city are you from post me
1:39 That's my 3D printed radio video!! :) Thank you for sharing.
Oh great
Nice
A project that I can afford! Great!
Enjoy!
Great .. Next challenge : Make ONE Switch radio control circuit (Rx and Tx) with basic transistor and crystal circuit .. no ICs ... 100m - 1km
Hello Mr. Walid I am your subscriber when I was 14 years old now I am 18 thank you for your lessons I learned a lot from your videos
This is the dream! I've been wanting to build an RF switch (both RX and TX) for YEARS and I couldn't. Even my professors back in my uni days wouldn't help.
Yes using RF modules would solve it, easily, but defeats the whole purpose. I want to build it from scratch!
It's great to see an electronics master challenging another electronics master :)
Maybe you can do this video together? :)
That would be cool, especially in the manhattan style circuit board for good measure lol Come the day of the Internet apocalypse, it could prove to be very handy.
Yes, regenerative plz and LC tank osc. Am waiting for that
would´ve been cool to build an actual oscillator based on discrete components instead of using an timer IC ;)
Back then, there were no ICs inside tube radios 😁
My first am transmitter had only one transistor and worked fine!
@@brankotdk I´ve seen AM receiver which had no active electronic components at all.
Only a coil, few capacitors and resistors and a crystal earphone.
@@MultiWirth sorry for my English... That was probably detector recever. Works without battery. You need also diode (I used germanium diode).
@@brankotdk it was a "rocket radio" from the ealry 60's.
It was a crystal radio (the crystal in this case was the earphone itself) which actually works like a diode but can only pass a very low current as far as i know.
Radios from the 30's worked similar, but had a amplifier tube and and speaker.
And of course no 555 timer IC 🤣
@@MultiWirth the titanic reciever
The "easiest" AM transmitter would be to feed both the oscillator and the audio through capacitors, connect the output of both capacitors together, and send it through a common-collector amplifier with no bias voltage on the base. The effect is a carrier signal that changes amplitude based on the audio strength.
i think its an overkill to use ICs for AM communication. it can be done with a few transistors with great quality
More analog circuits, please! Thank you for your work :)
nice Video, can you built a DAB+ Radio ? with an Arduino ?
I can put it on my to do list.
I'm glad you posted this, because i want to create one for my tube radios
You're welcome :-)
I would think learning a bit more theory would be in order before posting a circuit. But that's not fun?
I'm glad we're going from STEM to STEAM, arts are important and can be a great part of science!
The addition of this vowel will certainly minimize the number of possible candidates.... Not widen it 🤣.
Just like how adding science to arts does the same thing.
@@jamess1787 what do you mean "minimize candidates"? The more the movement covers, the more interested parties there can be involved. It's not like a person is forced to do anything in particular with a program, it's just about encouraging and fostering learning and skills
I've been looking at making something like this for the past week! Amazing timing
Perfect!
Hello sir. I am a 13 yrs old electronics enthusiasts and I need some help. Can I contact you. I don't think so bcoz I think he would be busy.
@@greatscottlab
Hallo, greetings from Venezuela.
Thank you very much for your videos they're so cool and helpful!
I've been researching a little bit about IC that could function as a replacement for the TA7642 of your AM RX and I found out this two ICs the TA7640 and the TA7641, would you recommend either one of them to be used in place of the TA7642?
Thank you very much for your time and help on the matter, I really wish you're having an excellent day! Tschüss! :)
Its a magic "Summon the FCC" circuit!
Well, he's in Germany, and HAM licenses there are called "Amateurfunk Prüfung", so I'm sure he'll be fine. I'm sure he's got enough funk to pass it.
Not at all. Not enough power to attract attention even if he lived in the US. Yes I have a HAM license.
Nein. Night von Deutschland.
wireless technology is always cool, can't wait when Great Scott will soon build up a remote control circuit with just a basic components locally available without a complex IC. and i always dream about it
Stop dreaming, start doing.
Cool project!
Thanks😁
What how four day ago?..?
@@TECHiHOBBYIST Patreon.
Please make a Laptop operated Drone project through Arduino or own circuit
I got a simple project that i can built this week, thanks :)
Have fun!
I tried to make this one, I used 12v as power supply and I tested t 3m away and when I am touching the output the signal increases and as I don't the signal disappears, why is that so? Can someone explain me?
Maybe you are an Antenna
*you forgot to add the "super simple" part.*
Amazing! Finally a project I can build without much hassle ;)
We've got you surrounded! Come get an HF band license
~ Federal Communications Commission
@@bat4 I WILL NOT GET A CLASS 1 HAM RADIO LICENSE I WILL NOT GET A CLASS 1 HAM RADIO LICENSE
Did you watch the whole vid already
@@serignebah4788 i watched it 4 days ago
Perhaps that will be from ZouTube not youtube
I made crystal radio when I was 13 years old at that time people around consider me scientist 😀
That's so cool! Did you have a kit or something?
I made a line following robot car and they thought the same😜
@@N0Xa880iUL no I don't have any kit I made it by my own using a cardboard roll and wrap wire around it to make inductor and using razor blade and pencil led to make diode and a gang capacitor for tuning
@@alexmustang8177 That's genius
@@tanjiro3285 Wow! And how old were you
Install a coax cable with a sma connector so you can improve the antenna.
12 second ago
Hi
Es wäre vielleicht eine bessere Lösung einen Quarz zu nehmen so dass man einen Sender hat der stabil auf 1MHz oder 6MHz senden kann die Modulation kann man über einen TL494 machen da dieser sehr linear die Pulsweite verändert wenn sich auch das audio Signal verändert die Antennen Anpassung ist auch ein wichtiger Faktor der beste Sender bringt nichts ohne Antenne . Damit die Oberwellen gut unterdrückt werden könnte man einen PI Filter benutzen mit welchem man auch gleichzeitig die Antenne anpassen kann . Wenn man nur den Träger haben möchte ohne Modulation waren es dann bei 12V Versorgungsspannung nur 6V welche die HF Endstufe bekommt und das audio verändert die Spannung zwischen fast 0-12V so bekommt man etwa 100% Modulation das Audio klingt dann deutlich besser :)
You can build a much simpler FM transmitter and receiver both using only one transistor and a few support components. Look up "FM Bug"
I think so I am late
But here marking my attendance
And enjoying the video
Hope to get some deep soviet codes via this signal lol🤣
This was a VERY fun video. and I learned about a kit vendor I never knew about, kiwiCo. Thank you!
Engineer you can make easy simple mobile network booster without Ardino
In spite of what someone else posted earlier, you can operate an unlicensed AM radio broadcast station in North America by an agreement made between Canada, U.S., and Mexico as follows:
Unlicensed broadcasting - 100 mW DC input to final amplifier with a 3-meter maximum length radiator, no license needed, may be measured at edge of campus for school stations.
Very cool sponsor this time!
Wow! Greatscott! You just play music with your function generator!!! [5:19]
Yes ;-)
@@greatscottlab yesssssssssss >:3
So cool
Went back in time to 1980s with my crystal radio receiver.....
Build a a portable laptop
Man, too much bloat. The transmitter can be built around two or three transistors. Same for the receiver. The art of discrete electronics is lost!
Agreeeed
Ayo stop talking shots at your comment section.
1:39 That's my 3D printed radio video :)
I want to build some simple short range walkie talkies for my job. So your videos have helped me determine the components I’ll need.
Very good
Slightly off topic question
What do you call the leads with the springy hook ends?
Hello bro please make mobile signal jammer
I used an RC remote to make an FM transmitter.
Bhai aisa kaise kiya muje v btao
@@shriniwashasefirst select an empty fm channel for ex you choose 94.5mhz station in reciver press button of remote and with the help of screw driver rotate a black thing you will see in wrapped around coil. You will hear a around 1000hz tone.
find in pcb from where around 1000hz tone is generated. From there add audio input or audio can be input in series with battery.
Audio can be inputted from mobile phone using aux cable
@@Vivekstark68 kaha se late ho itna Dimag
@@shriniwashase khud se different thing bana ke dekhta rehta hu
Damn this was literally my final project for a lab class a week ago lol
Great Work! Greetings from 🇮🇹
youhave come to your senses. usong simple ics instead of microcontrollers. tobuild a radio.
A 555 is a filthy triangle wave generator, and the signal generator chip can do FM or PSK, still oddly under- and over-engineered solutions, but certainly more informative than using an arduino timer to make AM radio bleeps, or the pi clock to spam FM with square waves.
Actually, hex inverter, eg. UB4069 will be simpler, work better than that and draw less current.
Even if Xtall be used as harmonics we can reach up to 300MHz with very clear transmission (AM or FM).
Just make sure make a very simple class A amplifier with 2SC9018 transistor
For receiver, please don't build bird nest version like this, just attach in PCB with wide ground plane, it will give a huge stability.
Greetings from Indonesia 🇲🇨
I think I'm on right channel thanks Scott for great videos
finally a project that doesn't require a 300k dollar quantum CNC...
But still you need a DSO to analyze the waveforms
@@danielchopra6686 Or wing it and adjust until things sound Okay :D
@@yeetusdeleetus
☺️ yes we can but it's gonna be tedious and also we'll miss the fun playing with the DSO
every inhale. take a shot
Thinking quickly, GreatScott constructs a homemade AM radio transmitter, using only some solder, a microphone, and a 555 timer.
That moment when messing with the knob actually sounds good 5:35
To much information 😂
Love from India❤️
Who listens to AM Radio XD
Hi GreatScott, how about using a multiplier IC, such as AD633, and follow the AM math equation? Great video!
The correct method to generate AM. Am = (1+m)c is the general eqn. for AM. where m = message and c = carrier.
I bought the xr2206 unit and ran into two problems. In my version, pin one of the IC was grounded so I pulled the chip and bent the pin out so it was no longer grounded. I then tried sending a signal to it using a cassette deck through a one chip mono amp. It worked but was very distorted. I tried a number of things to resolve this but nothing worked. Any ideas? Suspect severe impedance mismatch but can't figure it out.
It would be really good to see the transmitter made from discrete components - go old school! Nothing more complex than a transistor...
Slightly off topic question
What do you call the leads with the springy hook ENDS?
@@pdemosllegaralos520subs2 test leads in general, clip leads or test clips more specifically, or hook clips when comparing to other clip leads.
Actually, running that 555 output into a tank circuit (probably with a buffer amp) to make it resemble a sine wave and modulating the power supply voltage with the audio would work pretty well.
Nice little boombox Panasonic Ambience stereo is a very nice feature for their boomboxes
Yes because we are capable of our own networks. Right now Pakistan is limiting people's cell phone coverage to only those who are vaccinated so having such independent Is critical for speech free. It is also off their grid and connection to the Internet of all things.
Get your HAM license and you can transmit from 1800 - 2000 kHz LEGALLY!
I'll take a look at this video later, but lemme say thank you so much for brinign back life into such an old topic. Back in school in 2016 i successfully but an AM transmitter only using 2n3904 Transistors (Hartley Oscillator), and i wanted to build the receiver to go along with it, but none of my receivers ever worked. I've tried SO many configurations without "cheating" or using too complext ics, i wanted it to be a receiver using NPN transistors too, but the main issue is idk how to properly measure or deduce why my circuits never worked. Wanna say thanks again, i feel like there's hope for my project again. If yall are interested i can get the schematic of the transimtter that worked at lest. Thanks @GreatScott!
hey i had the same issue, it's real frustrating
maybe try this circuit
www.talkingelectronics.com/projects/TheTransistorAmplifier/images/Fig71bd.gif
you don't need the transformer, just connecting the speaker from 3v to the collector of the last npn transistor works fine. And make sure to put >22uF decoupling capacitor across the supply so there's no unwanted noise.
2n3904 and 2n3906 transistors have worked fine for me.
Only problem is that the output sound is really small. Maybe you can replace the speaker with like a low value resistor and then add a class A amp after the last stage. (don't tinker with the other stages, doesn't make the sound louder, i tried yesterday)
hope it helps :)
@@Kevin-jz9bg Thank you for the reply! it REALLY means alot to hear that there are others that tinker/deal with this kinda stuff given im a noob. I'll definitely test this. Here is the transimtter i used to build it. Its based on a radio project from a RadioShack 300 projects in 1 kit. I took their morse code transmitter and added my computer speaker input into it. i broke it up into 3 stages because it was easier to draw lol.
bubbamachina.files.wordpress.com/2018/04/am-transmitterpng.png?w=666&h=1024
@@bobbysamuels1308 thanks for sharing!! I'll try to build it and let u know how it goes!!
For the inductor in the hartley oscillator, can I just take an am inductor from my am radio and tap the center? (it's 55 turns on 1cm * 10cm ferrite rod)
I'm a total n00b too but hey "it's super cool, which I think should be the only prerequisite for doing science." - Physics girl
U shud check out talkingelectronics.com for a buttload more of projects :)
i recommend buying some generals purpose npns and pnps in BULK and just building whatever seems interesting: www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P2.html?ref=driverlayer.com
Hello
Interesting.
I made an Am transmitter with the 555 a couple years ago. As I remember 600- 700 KHz is about the max you can set up the 555 to oscillate at. Mine did work. It had horrible harmonic issues and was all over the place. I had used an audio transformer to modulate the carrier.
Did it work, yep but..... not exactly clean at all and likely not worth the effort to filter....
Kiss. Keep it simple stupid. Live by it makes life a lot easier
It Is Not Called Transmitter And Receiver, It's Called Tranceiver ! One Word .
Nice transmitter, but how to amplify the ERP (effective radiation power) to like 10 or 20 Watt?
Well, I will not tell you due to legal reasons.
@@greatscottlabOkay, good point, I'm fine with that ;)
You need to study for a general class license using them kind of watts. Most amateur radio is home made when one cannot afford to fork out a few thousand dollars for a built unit.
Hallo @GreatScott! , greetings from Venezuela.
Thank you very much for your videos they're so cool and helpful!
I've been researching a little bit about IC that could function as a replacement for the TA7642 of your AM RX and I found out this two ICs the TA7640 and the TA7641, would you recommend either one of them to be used in place of the TA7642?
Thank you very much for your time and help on the matter, I really wish you're having an excellent day! Tschüss! :)
I like simple. I used a 6888 vacuum tube, a tank circuit, and a TTL oscillator, with a triode to drive the screen grid. Works great. I get about 5 watts of RF.
I know I'm a bit late, but do you still have the schematics for your circuit?
can you please share schematic diagram of TA7642 circuit
You can't reach 100MHz regular broadcst frequency with 555 but you can easely produce phase modulation with it, that can be demodulated by a FM receiver. If you buy an old army wolky-talky (various models have various bands but in general they start at around 30MHz to around 55MHz-60MHz and small ones (several kilograms that is, sized as a small netbook with 3 times its thikness) are ususaly from around 40MHz to 47MHz) and find 555 variation that can reach 40MHz (both are accessible) you can try it.
Why should one use an integrated circuit, when the same or even better results can be achieved with one or two transistors and a few passive components?
i want more thorough explanations. stop giving half efforts. this video is bad.
Can you, please, show us how to make a better am transmitter;
Nice reciver btw.
Hey GreatScott, have you also considered trying a circuit like keystoneSience did in his video (th-cam.com/video/O3SuM5Z2S78/w-d-xo.html)? It uses just two components and works also reasonably well
I have also introduced a digital FM receiver in my channel, build and have fun
555 as an AM digital transmitter!
It's actually a FM transmitter, but because of the way AM receivers work, it's a hacky way to do the job. The AM transmitter is looking for a signal at its tuned frequency. As the carrier moves away from that frequency, the receiver sees a reduction in signal strength on a bell curve. So an FM transmitter centered on the same frequency will cause the same reduction in signal strength, by moving away from the tuned frequency instead of by adjusting the carrier strength. So it "works", but it also interferes more with adjacent channels as it encroaches on their band.
@@ovalteen4404 Cool! Anyway, this looks like a data transmission project using AM/FM. What do you think @GreatScott ?
AM, the frequency no one uses lol
CV PIN to "smuggle" in our audio signal. This is so funny 4:06
This was my capstone project!
Can't we use arduino based wireless components to make it very simple?
Enjoyed video regarding the transmitter build. It's probable that your circuit likely complies with Part 15.209 if you need to keep the radio relatively close to the transmitter. Your video will certainly be of interest to the would-be Part 15 broadcast enthusiast who wants to build their own transmitter before graduating to one of the more costly, high performance Part 15 AM transmitters. Thanks for sharing.
Why do it easy when it can be done more complicated. A TL072 can be used as colpitts Oscillator and OP with variable amplification done by a JFET in the featback. The NF signal goes to the gate of the JFET. The SA602 or SA612 ist a mixer with build in oscillator. Both gives real AM without any detours.
Antenna coil using a coil form made from a business card- use a small piece of hookup wire between the former and the ferrite rod to space it so that it can be moved for tuning. 1 transistor colpitts oscillator + modulation into the base. 1 transistor reciever... into an earpiece using another ferrite rod coil on former with fixed capacitor. maybe a movable tickler feedback winding to cause regeneration
what software do you use to design your schematics?
Please Build Home Protect Circuit High, Low, Delay Circuit with LED indicator Using Relay...🙏
In the U.S. (no idea in other parts of the world, but probably similar) without an F.C.C. class 'C' license (now known as a "technician class"), you can not operate a radio transmitter, A.M. or F.M. with a total broadcast output of greater than 20 watts or a transmission range of greater than 20 miles. This is *only* when using a transmitter whose design and commercial manufacture have been pre-approved by the F.C.C. In the U.S. this is from the regulation congress passed in 1987 that allows you to use your citizens band radio, and radio controlled models and toys without an F.C.C. class 'C' license. An addition was added to that regulation in 1995 to include the unlicensed use of your cell phone (your cell phone is just an F.M. radio transmitter and receiver). A non approved transmitter such as a hobby built unit can not exceed 2 watts total RMS at the antenna, or about a 500 yard broadcast radius unless the actual transmitter part of the circuit is a sealed unit with F.C.C. pre-approval. Whether or not some F.C.C. official is hiding in the woods to catch you broadcasting at 5 watts, I leave to your imagination.
As for using a square wave generator (555 timer IC) as a broadcast Carrier Wave, all you need to do is scope the CW signal at the RX antenna to see why it's a crappy idea. You may be "sending" a square wave, but the receiver antenna sees a spikey, bipolar, saw tooth (more like an inverted shark's fin) wave form. This make's it extremely difficult to filter out the overtones and sub harmonics caused by the spikes.
LMC555? I would have thought it could be NE555.
I thoght you were good at electronics Scot.
But you always use the 555 timer for all OSCILLATORS pls use other old school or more like I mean arable multivibrator for future projects
Shades of listening to Short Wave on my Radio Shack 65 in 1 kit
Got you beat on stupid easy AM transmitter.
I used an LM386 to boost the audio from my 3.5mm into a small audio transformer and into a full can oscillator. You can get them at many frequency's the higher the longer range.
only using FM band is illegal. AM (LW, SW1, SW2) is good and even in poland is allowed only not on 225 khz beacouse there is 1'st poland radio working from 1929
well, it is legal on low power in Australia as long as you are under 3W you should be fine, with HAM stations, 5W with a armature license is fine, just don't be a d*** and start punching it up high.
I have a AM transmitter just down the road from me- commercial and I'm able to hear it right to the border of my state... my state is larger than Germany, as they are only using a 2kw transmitter it could possibly even make it to Antarctica by bouncing off atmosphere and water.
I’ve seen fm transmitters for sending audio to car radios for drive ins for about $35. I wanted to buy one to watch movies with my friends but I would love to see if it could be built for cheap using standard components. Maybe a cool diy or buy?
You can get some for much cheaper direct from china on the usual suspects (AliExpress, banggood, gearbest etc...)
I've found a Bluetooth to fm transmitter for 2.46€ on AliExpress.
In the 90s i took a gadget made for amplifying ambient sound to earphones and reworked it so audio output from Walkman was amplified and output into several small tv speakers mounted in a box. Essentially the first cordless personal speaker. How could i have made it more powerful?
Hey Scott! Awesome video, but this AM waveform on 3:04 is not the best honestly. I get it, it's hand drawn, but it really got to a mix of AM and FM :)
As a tip for the next time, you could've drawn straight vertical lines with pencil to indicate where peaks of carrier are and should be in resulting signal :)
Making FM transmitter is also very easy but receiving is bit harder(super heterodyne)
Yes, true
Pls make more oscillators you showed basic ones can you show more more basic oscillators pls pllllss PLSSSSSSS!!