AM Transmitter Build Project and Demo
Вставка
- Опубліковано 15 лис 2024
- The P-C70-OSC may be hard to find. In these video you make the oscillator coil.
MOSFET AM Transmitter Home Made Oscillator Coil
• MOSFET AM Transmitter ...
MOSFET AM Transmitter Home Made Oscillator Coil PART II
• MOSFET AM Transmitter ...
Rick, I truly enjoy watching your videos; you explain things so clear and effective that the person without electronic background can understand and not get overwhelmed. Thank you so much for taking your valuable time and teaching us your techniques so we can build AM transmitter to enjoy lessening to these AM radios. Have a great day! Regards, Jay
Thank you, Jay. I appreciate your comments very much. I have a Free eBook. You can download by clicking on the link.
PASSWORD is allamericanfiveradio
drive.google.com/file/d/1HHmaWYr7UMACfmS4W5uL6PADoem2KlRp/view?usp=sharing
For those looking to build an AM transmitter, here's a beauty. Rick, I have to say that P-C70-OSC coil is a good one to start with.
I had great results with that coil. And using your design I had it working in no time. I highly recommend this one.
Thanks Carl. The circuit should be about the easiest one for beginner to have success with. Plus it's something useful too.
I'm from brazil and would like to thank you for sharing your knowledgment with the world. I'll try to make this AM transmiter, the coil will be de hardest point, but i'll not quit!
sorry for my rusty english
Thanks and your welcome.You might try eBay for the coil.
Rick, I’ve been following for a few years now and can’t tell you how many times I wanted to ask you for something like this. I bought the AM talking house and that thing is garbage. I tried to build a few but with no luck. This simple LC tank circuit looks to be something that will work. Parts are already in the mail. Thanks for sharing and teaching us.
Let me know what happens I'll be glad to help
@@AllAmericanFiveRadio I put the power supply together on a breadboard. Working perfectly. I can't get the transmitter to work. Pretty sure I have the coils correct, verified w/ ohms read. I have a frequency counter. I've connected it to the antenna and the ground and it just reads 50-60 hertz. I put the trimmer capacitor at 300 pF. Not sure what the issue could be. I'm using the SG9058-ND trimmer and the coil you suggested from the source recommended. Non of those capacitors have polarity so I'm not sure what I could be doing wrong.
@@MrTysonjharris Does it work without an antenna and ground?
@@AllAmericanFiveRadio I does not.When I connect it to the power supply and have it near my AM radio I get distortion on every frequency I tune to. I've ordered new parts except the trimmer and the coils and will lay it out again on the breadboard. Can you confirm for me the direction of the coil? www.amplifiedparts.com/sites/default/files/uc_products/p-c70-rf_nohat_1.png Using this orientation, to the right of the red dot is which 1 or 2? Note: I've recapped more than a dozen radios, pretty confident in my abilities. Sort of a head scratcher why this isn't working. If you were going to use a frequency counter to verify the coil was oscillating where would you tap into the circuit? - Thanks
@@MrTysonjharris Yes I was thinking about the coil. The information from Antique Electronic Supply is shown as a bottom view. I wish they would have labeled it as such but they didn't. I went to their website and they have more information than what comes in the box. Here's the link.
www.tubesandmore.com/products/coil-miniature-adjustable-coil-70-oscillator
That is a very interesting circuit, especially when you made that with a MOSFET. Very good, also that you show the practical circuit. And the modulation is also very very pure, thanks for this upload.
Thanks radiofun232
it is a very simple circuit but I think it performs very well. I'm hoping that the circuit will be successful for the beginner. I'm sure you know it's a little trickier building a transmitter because of RF. It can be a challenge for the beginner to keep the RF out on the antenna. Rather than have it go into the power supply or it having find a path to ground.
@@AllAmericanFiveRadio Thanks!
Sadly, we no longer have a Radio Shack, or any other electronics shops to get parts from in my town.
Thank you for the tutorial.
Thanks.I now use eBay.
Rick, another fine innovation you've shared with us. Thank you so much, really really appreciate it. Ron
Thanks
well it sounds like a little Old time radio going on over there and I am a big fan of Johnny Dollar, and any of the old Lux radio theater programs...but the best part about this transmitter is the simplicity of it yet its quality and clarity are not sacrificed. I have been tinkering around the bench and considering building a transmitter but I am not sure yet if I want to build it Am or Fm .
I enjoy Johnny Dollar (Bob Bailey) and have many on cassettes and CDs. I use both AM and FM transmitters and they both sound good. It depends on what radio I want to use.
Both transmitters simple and almost the same circuit. Here is a FM transmitter.
Build FM One Transistor Transmitter Project Modification 3-3
ua-cam.com/video/3tc3gBEU9Js/v-deo.html
FM Transmitter, MOSFET Experiment
ua-cam.com/video/Aerr6v6Vwgk/v-deo.html
I have a talking house brand AM transmitter. I need to build or get an 18-volt power supply. The original supply has a ground prong at the wall. Too bad it wasn't at the thrift store with the transmitter. An 18-volt dill battery will power the unit fine for a few hours.
Yes, the power supply will save a lot of batteries, and money. Hopefully you'll be able find a power supply that will work. With batteries you might try running it on 12 V DC because a 12 V supply would be easier to find. Thanks.
@@AllAmericanFiveRadio I might be able to use 12 volts. But once the voltage goes down on the battery, the automatic adjustments go all over the place. This box can transmit on any frequency an AM radio can receive by using some sort of motorized tuner. That motor turns on when the power drops.
A couple of options here... You can pick up another 18V battery charger and modify it to work at a constant 18V. You can also use an old laptop power supply. Most of those are at 19V. The one volt difference isn't going to harm the transmitter. You can also modify some of the older HP Printer power supplies. Most of those are at 32V. A voltage regulator and a few discreet parts and you can build it right into the Talking House.
Wow, what a great AM transmitter! Where did you purchase your MOSFET? Also, I believe I have the exact Osc. Coil but if I remember right - the connections to it were a little confusing. I know there's a little red or black ink dot on it. I'll have to see if I still have the diagram to that coil. Great video, thank you!
You get the diagram of the coil with the coil. You can get the MOSFET from Mouser. Sometimes I use eBay.
good work, nice and smple design, is that coil readilly available ?
THANKS!
I recently checked on the availability, it is available on eBay for $58. That is why I did these two videos.
MOSFET AM Transmitter Home Made Oscillator Coil
ua-cam.com/video/8jV5rfc-QhA/v-deo.html
MOSFET AM Transmitter Home Made Oscillator Coil PART II
ua-cam.com/video/RmRXnimNx58/v-deo.html
I'll have to see if I can pick up the coil here in Scotland! It seems to have a decent range which can be a problem on some transmitters I've encountered which practically have to be touching the receiver to get a decent response!
Add a larger variable cap in the tank circuit for AM Transmitter
Build FM One Transistor Transmitter Project Modification 3-3
ua-cam.com/video/3tc3gBEU9Js/v-deo.html
Awesome build Rick. Has with all you great Guys and Gals,I liked,Shared,Added to playlists. All my best.
Thanks
thank you for making this video tutorial I love the many lessons I took ....
Thanks and your welcome.
Thanks for the video. I didn't understand a detail in the schematics, where the points 4 and 5 of the coil linked to ? are they coming from another oscillator providing the carrier frequency ? and is the carrier frequency limited by the transistor in the center ?
They are open, not connected to anything.
@@AllAmericanFiveRadio Thanks for your response, but in this case, how do they contribute to the functioning of the circuit ?
@@marouaniAymen 4&5 are not used they contribute noting to the circuit of the circuit.
@@AllAmericanFiveRadio Understood, thanks
Thank you very much for this video. I was looking for a good scheme and now i have it all.
Thanks
I was looking for a AM TX schematic, and this is what I need. Thank you, Subscribed de KC1ATW
Thank you. I do have several other videos on transmitter's. Some are FM transmitters. The circuits are very similar, mostly the difference is in the tank circuit. Just do a channel search on transmitter's on my channel.
How much it's range? Did you test the range?
It will cover the house and some out side.
Nice circuit. For some reason I couldn't get it to oscillate with the IRLB3034PbF HEX FET (Ebay) but it worked with any other N-FET I tried (IRF520-630). It also works great with an 100uH to 150uH and a 10uH cheap ebay inductors in series. It's a realy beautiful design with only a few parts and it realy works good. Thanks for sharing!
Thanks.
I would test the IRLB3034PbF HEX FET to make sure it's good. If it is good try running the transmitter on 24VDC. I wanted to design a circuit for the beginners so that they would make a successful build. My FM transmitters are of the same design and work very well.
@@AllAmericanFiveRadio I checked the 3034 FET and it tested ok. I also tried 4 more FET's from the same batch without any luck. I only ran it on 12V-18,5V (the supply I used didn't go higher) but I will try again with 24V. Thanks again!
Btw: If I wanna match/tune in my antenna can I just mirror the" LC tank circuit" from the oscillator and put in series with the antenna? 🤔
@@eivindamundsen7090 Here are other experiments, hope you try them.
Build FM One Transistor Transmitter Project Modification 3-3
ua-cam.com/video/3tc3gBEU9Js/v-deo.html
FM Transmitter Varactor Diode Modulator
ua-cam.com/video/JQGWr2dPe4E/v-deo.html
FM Transmitter, MOSFET Experiment
ua-cam.com/video/Aerr6v6Vwgk/v-deo.html
I tried this with a couple of scavenged 100uH and 10uH inductors but it didn't want to oscillate. Would you happen to have a link to the inductors you used as I can't find the OSC coil Rick used here in the UK?
Thanks!
the distance between components and the ground size changes the frequency
thanks for the video! would you mind tell me the inductance of you coil or many turns?
I found a coil to measure and the results are between 1 and 3
R=6.0 Ohms
L=0.10mH
Can not tell you the number of turns. I would have to unwind it which would destroy the coil.
Great video, but can we have more information about the coil? how we can get it or build it?
www.tubesandmore.com/products/coil-miniature-adjustable-coil-70-oscillator
Very interesting design for the AM transmitter. I noticed however that the mosfet you used is rated at up to 343A of drain current. Would not mosfets with much lower drain current work?
I would think most any N channel MOSFET would work. I'm using this one because that's what I have on hand.
@@AllAmericanFiveRadio I have piles of N channel Mos fets logic level .. I looked at your Circuit and wondered how critical the FET was.. Then I saw the 500 ohm in the source to ground path and realized the max current was very limited. Did I miss some other multi amp path? I have some 30N06L mos fets with Source Drain currents in excess of 30 amps. I'll try one
That audio sounds like the sound track from the movie "It Happens Every Spring", circa 1949. Did you get some wood repellent with the tape?
Yes it is, but no hair tonic came with it.
Hi Rick! I want to try this circuit out. However I having a hard time finding the trimmer that you suggested? Is there an alternative value that you might suggest? Thank you for the great videos! Brendan
Hey Brendan, I bought the variable capacitor from RF Parts www.rfparts.com , they may not have the exact one I used but I think you should be able to find a suitable substitute. Hope this helps. Rick
@@AllAmericanFiveRadio Thank you for the come back and the help! I will check them out? Brendan
Sounds great. I am going to have to give that one a try.
Good and thanks.
Nice circuit. I will build one, but I would like to know more about how this circuit works. As I'm still learning radio theory please feel free to correct the following if I'm wrong. First, an audio signal enters from the right past a voltage divider and current limiter resistor to the gate of the MOSFET. While this is going on the coil and variable cap are oscillating at a frequency somewhere in the AM band. The oscillation is sustained by the voltage tap from the power supply. Pins 4 and 5 of the coil are not connected as the secondary side of the coil (normally an IF coil) is not needed. To get modulation, the MOSFET partially shunts the amplitude of the oscillator's signal to ground in response to the audio input. The modulated signal is then fed to the antenna through the 68pf capacitor. As for the parts, I'm finding that the coil is easily obtainable but the variable cap is larger than most available from the radio supply houses. Can I assume that a 15pf to 365pf capacitor will work as well, though maybe not for the full range of the AM band?
The two 10,000 ohm resistors that are connected at the positive and negative are the biasing bridge. The audio that passes through the 0.047uF capacitor adds and subtracts from this bias, producing Amplitude Modulation in the oscillator coil. Let me know if you have any other questions I will be glad to help.
AllAmericanFiveRadio Rick - a simple and effective design. Regarding the AM modulation, does the modulation occur at the center frequency of the sine wave or does the modulated carrier(s) fall below and above the carrier frequency? Thanks for your time. Best, Don
Merci, very interesting! But impossible to find a P-C70-OSC for testing your schema.
I did make two videos where you wind your coil. I also added this information in the SHOW MORE of this video. Thanks!
The P-C70-OSC may be hard to find. In these video you make the oscillator coil.
MOSFET AM Transmitter Home Made Oscillator Coil
ua-cam.com/video/8jV5rfc-QhA/v-deo.html
MOSFET AM Transmitter Home Made Oscillator Coil PART II
ua-cam.com/video/RmRXnimNx58/v-deo.html
Hi! It seems very impressive little transmitter. What is the output RF power at 24V?
How can I connect the audio input (what is the input impedance and wattage)?
Thanks and Regards
It covers the house nicely. The same circuit will also work with 12VDC.
@@AllAmericanFiveRadio Thanks a lot! I'm going to built this transmitter with a single mosfet power amplifier.
Hello Rick, I hope this finds you healthy and sane. A little unrelated but hopefully you can help. I built the McWhorter AM Tube TX recently and I’m having issues getting audio into it. The input transformer was not specified and I’ve tried some stuff I had laying about but still no luck. Any chance you could steer me in the right direction?
The audio transformer is one that you could use as the output for a 50C5 or a 50L6. For the transmitter I'm using the transformer backwards. Using the transformer as a step-up transformer.
On the right track now. Thankyou sir! Modulating now with a temporary while waiting for the right one.
hello, was wondering if you can use an am oscillator coil (like you know, the one with red head/adjuster) in place of your 70-osc coil? thanks in advance.
An AM oscillator coil should work. I do have videos where you make the coil for AM and FM transmitters. Here is one video.
Build AM FM Transmitter One Transistor Project 1-3
ua-cam.com/video/6ZsQNtZZ_V4/v-deo.html
☺😊😀😁😂5 smile's learning AM and RF signal will definitely be testing this curcit for a education in AM.👍got one off the cheap 335hz on eday on 7v 15m with out amplifier may get 35m max at current and looking at a 2.5w booster for a bit better range and will need to upgrade for a 500m to 1km range for professional use on some stuff ive been working on.
Good Luck!
Could you use a variable capacitor and ferrite antenna from an old am radio?
Yes that may work
Nice Job Sir, Thank You !
Thank you!
The P-C70-OSC maybe difficult to find. I made another AM Transmitter with a Home Made Coil. Here is the link to that video.
MOSFET AM Transmitter Home Made Oscillator Coil
ua-cam.com/video/8jV5rfc-QhA/v-deo.html
MOSFET AM Transmitter Home Made Oscillator Coil PART II
ua-cam.com/video/RmRXnimNx58/v-deo.html
@AllAmericanFiveRadio I have built the transmitter from your video but am not able to tube in to the audio. I tried tuning the oscillator and variable capacitor to 455kHz but still no sound. Do you have any voltages I can check on the board?
I also tuned it to 890 kHz and only hear a high pitched sound. Could it be the MOSFET?
I'll take some voltage readings you can contact me at allamericanfiveradio@yahoo.com
Hey AA5Radio! I'm trying to make this circuit, as I find it VERY unique, but for the life of me, I cannot get it to oscillate. I've got the exact P-c70-OSC coil from antiqueradioparts, and the 3034 mosfet. I'm using a 365 pF variable cap (old one out of a radio). All parts are checking out good, but I simply CANNOT get the thing to oscillate as shown. the FUNNY thing is, if I substitute the .001uF cap for a .033uF, then it oscillates around 1MHZ, but CANNOT be tuned, AND, I can actually REMOVE the variable cap, and it still oscillates. What the heck am I doing wrong?! I've built it on a breadboard, and I'm pretty sure I've got it wired correctly. Thanks for all your videos.
Ohm out your oscillator coil. The red dot maybe in the wrong place.
hi rick .can you tell me about the variable capacitor that you used. what are the pf values? cant seem to find any thing that will work. thanks so much robin
Hey Robin, I bought the variable capacitor from RF Parts www.rfparts.com , they may not have the exact one I used but I think you should be able to find a suitable substitute. 495-48pF Hope this helps. Rick
Which transistor you've used?
195A MOSFET
Thank you so much
Thank you, and your welcome.
Hello again. I'm wondering, can a Bluetooth receiver be used in the audio input so as to stream music from a cellphone to the Bluetooth device and then through the am transmitter ?
That may work but all you need is an audio input
hi nice vid thanks could you tell me how many turns on coil, size of form and wire diameter or gauge please
www.tubesandmore.com/products/coil-miniature-adjustable-coil-70-oscillator
@@AllAmericanFiveRadio Thanks Rick
Great video
Thank you.
Sir thank you . What's the maximum range of this mideum wave transmitter ?
With an antenna it will cover about 100 feet.
Thanks for your comment.
Rick, thank you so much for your previous reply. Just one more question. On the schematic, you have 495-48. I don't think that it's a 495pf, that would be much bigger than the one you showed. I'm guessing that 47pf is the high end, and the low end wasn't stated. Anyways, I found a 4 to 50pf. Will that suffice ?
With 50pF you might get into the AM band, but for-sure you’ll be in the shortwave band.
@@AllAmericanFiveRadio so, 50pf should be the low end ? I have one that goes to 365pf ?
@@AllAmericanFiveRadio So your saying that the one you used is 48pf to 495pf ?
@@jerrymercer7683 I think I'll do a video on this. I'll start on it today. Stay tuned.
@@AllAmericanFiveRadio awesome, I thank you so much for your help and your patience.
Could you please tell me where the negative from the power connects. May seem like a silly question, but I'm new to SCHEMATICS and no one ever seems to show that on the schematic. I'm assuming that connecting it to the grounds is correct ?
Also, how long of an antenna do you recommend ?
In this circuit the ground symbol is the negative side of the power supply.
Any idea what output power, and what degree of modulation?
The power out is enough to cover two or three rooms. The modulation depends on the audio input.
@@AllAmericanFiveRadio so you do not know with what power and modulation you were working with. My question is serious, because not all transmitters can have high modulation, and the output power may be tiny
How would i use this with a crystal oscillator? Just replace the coil and variable cap?
Yes. You can use a crystal oscillator. This will limit your frequency to one choice. Here is a video on crystal oscillator.
Crystal Oscillators for the Beginner
ua-cam.com/video/xezzwJAZEQY/v-deo.html
Thanks, I actually want to limit the frequency by design. i have recently built a transmitter using an XTAL Crystal and LM386 that works quite well but the distance is limited. I have a few n-channel mosfets sitting around and figured i could use them to increase the range, just wasn’t sure how to wire them up, seems that every other tutorial is using BGT transistors.
thank you for the explanation, will try it
Thanks and your welcome.
Good luck.
No luck unfortunately. Can't get it to oscillate. Tried 12v and 24v. Anyone have any ideas? I even tried a 27-465pF air tuning capacitor. I bought all the correct stuff except for the variable capacitor. I couldn't get one with quite the range as the one in the video.
Send me some pictures. allamericanfiveradio@yahoo.com
Just wanted to report here that AllAmericanFiveRadio knew what the problem was right away. The oscillator tapped coil was labeled incorrectly. The red dot on the coil to signify Pin 1 was off by a pin. Everything works great now!
thanks so much , that helped a lot . thanks robin
THANKS
very nice!
only that coil cannot be reached just like that
you can't just buy that coil just like that
so unfortunately we cannot imitate it 1 2 3.
friendly greetings from The Netherlands!
Rob.
Hoi Rob, dat moet je wel aanspreken! De modulatie is ook heel zuiver, echt een super schema!
@@radiofun232 Hallo Ko,
Ja dat viel mij inderdaad ook op, je hebt helemaal gelijk! alleen die spoel?
Das wel een beetje jammer, het zou nu mooi zijn als je de spoel gegevens ook zou hebben!
Zat ook te denken ik heb hier ook de IRF510 liggen, misschien kan het daar ook mee.
(het schema lijkt trouwens ook veel op de JostyKit-HF65 het FM zendertje maar dan met de 2N2219A natuurlijk!)
sorry for writing dutch, back to english again now!
VrGr Rob.
@@hobbyrob313 Bedankt Rob.
Volgens de comment van Elvind Amundsen zouden spoeltjes van 100µh tot 150µh en een van 10µh ook moeten werken (in serie). Deze zijn wel weer een stuk makkelijker te krijgen. En als ik naar het schemaatje kijk van hoe de spoel is opgebouwd dan zou je als je de 100µh met de punt die niet aangesloten zit aan 10µh dan dienen als punt 1, het punt waar beide spoelen aan elkaar verbonden zijn punt 2 en de uiteinde van de 10µh logischerwijze punt 3.
Thanks
Hi, Can an audio transformer works instead the coil? thxs
No it must be an RF coil. I did some videos where you can make your own coil, three parts.
Build AM FM Transmitter One Transistor Project 1-3
ua-cam.com/video/6ZsQNtZZ_V4/v-deo.html
Build FM One Transistor Transmitter Project 2-3
ua-cam.com/video/2ihVw30vj8o/v-deo.html
Build FM One Transistor Transmitter Project Modification 3-3
ua-cam.com/video/3tc3gBEU9Js/v-deo.html
What about its range when 12v ?
Covers the house
nice work
Thanks
Would a 142UHY www.tubesandmore.com/products/coil-3-lug-oscillator-142uhy substitute for the P-C70? Your circuit doesn't need an audio pre-amp?
The coil looks good.
Thank you for your quick answer
Your welcome
Isn't the "Wall Wart" power supply already regulated?
No
Most Wall Warts have poor voltage regulation (if any) and even worse filtering. It's not uncommon to see 12V wall wrts putting out up to 15V. If you want clean audio from your transmitter, build the regulator circuit shown in this video.
A basic wall wart is usually an 60hz (U.S.) AC transformer, a bridge rectifier, and a filter capacitor. These aren't regulated and the voltage drifts with load changes. But, there are plenty of "brick" supplies which are indeed tightly regulated. Still, in this circuit, you don't need a regulator with an unregulated 12V wall wart. Just add another filter capacitor on the board (like 2200uf/25V) and bypass that with a 0.1pf.
What's the range?
It covers the house nicely
I can't seem to locate that coil. Could someone tell me where to buy it please?
www.tubesandmore.com/
www.tubesandmore.com/products/coil-miniature-adjustable-coil-70-oscillator
@@AllAmericanFiveRadio Thanks guys, I appreciate it.
Thanks
Thanks
I want to buy
Antique Electronic Supply for parts.
AM more complicated than FM transmeter
Build FM One Transistor Transmitter Project 2-3
ua-cam.com/video/2ihVw30vj8o/v-deo.html
Hi im Jerry please I have question about if Transforme how many time have turn and uH many thank please text me
Do you want to know how many turns per uH?
I mean turns uH I’ll measure by tester
Yes
@@jarien2 There’s lost of variable. Size of wire, size of coil, number of turns, air core, ferric core, and iron core.
Here's some calculators.
www.allaboutcircuits.com/tools/coil-inductance-calculator/
www.66pacific.com/calculators/coil-inductance-calculator.aspx
I ned one
So do I!
Thank you, and you are welcome.