QRP Minimalist CW Transmitter With One Transistor - 700mW @ 12V
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- เผยแพร่เมื่อ 17 ส.ค. 2023
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A minimalist CW transmitter built in less than ten minutes, using only twelve components ( including the low pass filter ) and a power output of 700mW @ 12V or 500mW @ 9V. In the blog article you will find the updated schematic and PCB board design.
73, YO6DXE
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For better results on harmonics suppression replace R1 with 47K, L1 with 10uH and in parallel with L2 put a 120pF up to 140pF capacitor. It should cut way more on the 2nd harmonic. I hope this helps a little. Check the blog article ( link in the video description ) for more detailed info and the complete schematic.
73, YO6DXE.
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73, YO6DXE
I built it on a breadboard in half an hour with less than optimal components and it works! 366mw without, and 107mw with lp filter, and no chirp at all! With some tinkering It would probably give more power. Nice little project.
Yes that is why I love it hehehe. Is simple, fun to built and the results are not bad at all. Even if I would only get 100mW out I would still be haply. 73, YO6DXE.
You can check harmonics by listening to SW radio. For 7.3 is 14.6, 21.9,29.2 etc... No need for oscilloscope. And the 10th harmonic is 73, haha.
Hahahaha i love the 10th harmonic 😅😅😅. Yes this is how I usually check the harmonics suppression of the filters for now. But you know... I was thinking about seeing the signal and doing properly measurements... not "by ear" 😅. Radio is a great way though when there is none of all that gear around. Thanks so much and have a fantastic weekend. 73, YO6DXE.
@@dxexplorer Yeah, I'm not an experienced ham, so I figured it wasn't news to you but I can't help blabbing.
@demej00 Hahaha you are so funny. Don't worry is not like I have a lot of experience either. Is good what you do because sometimes even if I have the info... you know... we get old and we forget. Sometimes this is good because people remind each other of other ways of doing things so is great.
The paper on foam is really nice!TNX
I know right ? 🤣🤣 I learned from my sister as she does a lot of handmade stuff and figured it would work well for us too 😁😁. 73, YO6DXE
minunat! simplu si distractiv :)
Chiar ca e distractiv. De stiam si codul sa pot face si legaturi in CW era si mai fain 😁😁. 73
I loved it ❤. I just 🤔 wonder if I could make with a mosfet. I ll try further in the future. Regards from Argentina 73
The circuit would be diferent but I think yes you could make a transmitter with a mosfet too. Basically this is just an oscillator.
Simple and yet has no chirp that I could hear. I agree as you noted that feeding into a Pi output filter of some sort would be almost a must but in a pinch this circuit, as is, should work nicely. Great for SKN 😀
Ohh God I love the way it sounds. It reminds me of the old tube transmitters. Is something nice and warm to my ears for some reason. Really happy there is no chirp. I just posted the article and in the schematic now I also placed a low pass filter. Something simple. I hate I can't make any harmonics measurements right now. But I will try to figure that out or someone may make it for me if the have the right tools. Can't wait to finish learning the code and have fun with it. Is too cute small as it is 😁. 73, YO6DXE.
@@dxexplorer I am going to give that circuit a try once I get a half wave end fed wire up on 40M. Hope you get on the air with it soon 😀 73, WA4JAT
@marknesselhaus4376 I keep trying to finish learning the code, but with little free time to do that... ehhh... we will see. But I plan that the latest by December to be able to do QSOs in CW. And because I want this so much.. the entire month of December will be strictly CW for me 😁. Good luck and let me know know it worked for you. Happy weekend, YO6DXE.
@@dxexplorer It has been many years since I learned the code ( 1974 ). I just learned it one letter and number at a time back then and whenever I was driving my car, I would read the signs along the way and convert to code in my head. Took very little time for me to learn and when I went with a friend to have him take the code test I just copied it for practice and found out that I had indeed passed. CW has always been my Go To mode 😀 Take care till next time, WA4JAT
@marknesselhaus4376 I've learned the code when I was 18, as at the place where I used to work I had a kid younger than me that was licensed. I got excited and started learning as well. But if I haven't used it for twenty years... clearly I forgot everything. It shouldn't take me long to learn it, I just need some free time and piece and quiet. Right now I have none of those hahaha. But I can't give up as my CW December is a plan I intend to stick to. I also want to make CW the go to mode to do QSOs. SSB is fun, but with CW the equipment to use and build is so much simpler. You can basically communicate with prety much rudimentary gear and that is fantastic. Well... time to write some stuff on the blog now, so enjoy the weekend and we keep in touch. 73, YO6DXE.
Great video I do like the little cw board de 2e0ree
Thank you Andy. I also like it 😁 so tiny and cute. But I will also put a simple LPF on the output as well for those that want to use it on air. 73, YO6DXE.
Thank you for all your wonderful videos, instructive and simple, love it!
Could you make a video on how to make a simple LP or BF filter for these small QRP TX builds as well?
Keep up the good work with your videos!👍
73's de SA5VOX
Not a bad idea. Maybe I will post one before the end of this week, or next week if I don't have the time this next days. Excellent idea. And thank you as well for watching. 73, YO6DXE.
will you show a like wise simple reciver build too, perhaps even a series with small simple amp 10w and bandpass filters 4,5 videos, that will be great. video 1 with this tx video 2 with a rx, video 3 with band bass filter, video 4 with a 10w amp, video 5 with a end feed antenna and impedans transformer, all with as few component as possible. but thank for this video. Im all ready tweeking this tx with multible xtals for multible channels.
Not a bad idea... except that it is not that easy to do something good with as little parts as possible 😁. I may simplify things a little and do maybe a simple CW transceiver ( monoband )... up to 1 W maybe... this will also include it's own filter. Then an amp also with it's own filter. I already have the videos on the impedance transformer and the EFHW antenna... so is no need to repeat them.
Very nice project! Compared to Pititico 2, how does it behave on air? Cleanliness of signal?
I can't test it on air as I don't know the code hahaha. But from the tests I did so far... they seem very similar. Maybe this transmitter is a bit cleaner, but that is because I "boosted" the Pititico a little to get the most power out of it. To be honest I can't wait to finally learn the code so I can use both of them to get on air. Actually... there are many more to come so I will play with them all 😅😅.
Hi! I like this project! I want to try and build this, but I only have axial inductors (those that look like resistors). Do you think it will work the same way? Thanks!
For the 5.6uH inductor that is what I also want to use. I didn't in the one in the video because I didn't had any ))). For the low pass filter on the output... in general is better to use a toroid. But if you can find an axial one with the same value as L2... I believe it was 1.45uH then you can. Probably the filter won't be so efficient... but it should still do the job. I am working on a version as well that I want it to look a little vintage... so for that I will make both inductors on PVC tube ))). As long as the values are right ... it will still be all right. The good part on L2 made from a toroid is that us a bit easier to change the value by squeezing or expanding the turns on the toroid to adjust the filter for the maximum output power.
Very nice mate, but please explain tbat a low pass filter is required.
Yes yes I wrote that in the video description. And the PCB board that I am making also includes one. Wish I had an osciloscope or something to measure if it actually needs a low pass filter. Some are a bit "dirty"... some have quite a clean signal with no harmonics. But I have a feeling this one is not that clean 😁.
Haha, when i saw the thumbnail and i read the title i thought that something must be missing. Really tiny like the fm bug transmitters. 700mw is great! 73
It is a fun one indeed. A lot simpler than the 10 min transmitter. Only that in the PCB design I also placed the low pass filter on the output. 73 buddy.
@@dxexplorerit would be nice to have an 1watt cw transceiver with tuning control for lets say 40 and 20m. All i can find is really complex circuits. The simplest is the pititico transceiver.
@sv2tcb If you have a little patience... your wish may come true. Not that simple like the Pititico, but not too fancy either. 😁
@@dxexplorer do you have any circuit or something?
@sv2tcb No... not yet. But I am trying to work on something. I just didn't had the time... but I have some ideas in my mind to build exactly what you are thinking about 😁. I just need to build it and test it. Not much free time now... that is why I asked if you have a little patience 😅.
Muy bueno👍👏👏
Gracias amigo 🙏. 73, YO6DXE.
73,de EA5HYW ,Tony.
Can a sound be associated with a wave? What frequency range do you operate? How do you make a receiver?
Of course it can be associated with a wave. Waves of the ocean come at a certain frequency... radio waves the same, sound waves are no different. The ones in the video ( sound ) are around 600 - 700Hz. About the frequency I operate... it would depends on what transceiver I am using and what band. Is a little complicated... lately I didn't had any time to operate on any band haha. On the receiver question... I have a few videos on receivers so far if you look back into the older videos.. and there is also a Playlist with all the receiver videos I posted so far. But I will try to make some more in the near future. Maybe some really simply ones. Not reliable to be used in a QSO... but who knows ? Maybe they will. But I like simple circuits so I will play with a few simple receivers too. 73, YO6DXE.
@@dxexplorer Thanks for the quick reply And the perfect explanation Once again Thank you
Always a pleasure my friend.
what was the last character before cq cq cq?
I'm practicing cw and I'm confused what that character is
Ohhh I don't think it was one. I was just playing around to hear the sound of the transmitter 😅😅. That is why the confusion 😁. 73 and good luck practicing. I should do the same.
I understand this projexct because I have built a similar one but only one question. How do you obtain that audible signal when you just only produce a high frequency signal on and off while transmitting (so of course it can't be heard if there is only carrier wave)? Or maybe there is a special set up or something from the receiver side?
Well... take the transmitter as a simple oscillator, same as a VFO. Basically if you tune a receiver on the same frequency as the VFO... you will hear the oscillator sound on that particular frequency. The transmitter is almost the same, except that the power output ( RF ) is a little higher and it has a fixed frequency because we are using the crystal. I beleive the output is AM but I don't want to say stupid things (ha). But since you hear both sidebands I guess it is AM. Basically we receive the tone generated by the oscillator. Not sure if it makes sense what I am saying, too tired after a very long day 😁. 73, YO6DXE.
Your comment doesn't make any sense but what I think the receiver just takes the difference between the signal receiver (in this case only carrier wave) and the frequency from the local oscillator at that receiver so probably the sound you hear would be judt that difference of two frequencies in audiable range. This would mean that I need a special receiver for CW 🤔 Do you hear this sound on a normal portable Radio tuned to amator band frequency?
*signal received
Yep... you got it right. I tried to explain the easy way (ha). Normally yes, for CW and SSB signals you need a receiver that can receive SSB or CW. With a regular AM receiver you may still pick up something depending on the receiver, but in order to hear it properly you will need a BFO ( beat frequency oscillator ). Basically another oscillator 😅. I just tested a receiver now ( AM broadcast receiver ) and see if I can hear CW from the transmitter. I can hear i am transmitting but it sounds more like interrupted static... not the normal transmitter sound.
Ha! I knew it! Thanks for checking and the comment.
I'm just getting into Electronics and someone recommended making a CW transmitter for what I'm trying to do. Can anyone recommend a store besides Radio Shack to get these parts? Could I buy one pre-built? Any help much appreciated
A pre-built one... won't help much if you want to get into electronics. The best is to build one from scratch and even if you fail it, there is still something to learn from that and you will learn the best how it works that way while trying to get it to work properly. Unfortunately I left US in 2018 so I don't know the situation on local shops there, maybe someone from US could comment also with some info. But I am pretty sure that on eBay or Amazon most of the parts can be found really easy. You can even build it Manhattan style for now since you just practice and this way you learn a bit about placing the parts in the right place. Patience is usually the main key when learning. I would help more if I could, wish I was closer. I may only come back in an year or two in US so... ))).
@@dxexplorer thank you for the reply I appreciate it
@joebotz1243 Always a pleasure. 73, YO6DXE.
Welcome to another $$$$$ channel.
😅😅😅
Sir,the coil consist of how many turns?
Have a look in the blog article for details on the projects presented here on the channel. You can download the schematics and read a little more details that I don't always have the time to put in the video. 73, YO6DXE.
Hi mate with is your dummy load. Modal maker??
I will right back.. I need to watch the video again as I don't remember 😁
So... the dummy loads I used are all DIY. First one ( the little one ) is a 50 Ohm 1W resistor soldered on a BNC that I just plug into the antenna connector of whatever I am testing. I covered the resistor with a pen cap. The second one ( the wattmeter ) is also a DIY that I presented here in one of the videos... and is also on one of the blog articles. 73, YO6DXE
Hi. What should i replace to make it works on 80 meter band?
The crystal that is for sure. And the low pass filter needs to be recalculated. But I will do some tests tonight for 80m, 40m and 20m and put all that info in the blog article. The value of L1 may need to change as well.
@@dxexplorer Thanks. 73
@karkuwaa Doing the tests as we speak. I'm getting there. Dinner time now and after I get back to it )) 73
@@dxexplorer Take it slow.
@karkuwaa ( 80m band ) C3 390pF, L1 22uH and of course the crystal 😁. I still have to play with the bandpass filter.
I think I'm the only one that doesn't work. I built it with the d2061 power transistor just like I tried with the 2n2222a and it doesn't work. I don't know if it's because of the capacitors that I put in it, which are 104x2 and one is 103.
, and I looked at the carrier signal and nothing even until I tried to receive it with my sdr
That should work but the circuit I built is the complete opposite. I would appreciate if you could help me
Send me an email Juan. We will get it working. Send me some photos too if you can. Maybe I can figure out something from the photos. You have the email address on the contact page on the Blog.
Hi! How did you antena for it?
I am using an End Fed Half Wave for 80m to 10m band. But any properly made antenna for the 40m band should work well. You can even try a magnetic loop for the 40m band since is a fixed frequency and is small and easy to build. 73, YO6DXE.
@@dxexplorer Thank, you!
@lesykyavorskiy7630 Always a pleasure my friend.
It's nice transmitter for it's size and simplicity😄,
Why won't you consider trying to build something bit complex??
Because I really love simple circuits. And mostly because sometimes the simple circuits work just as well and do the same as the ones a bit more complex 😅. The truth is that I have a long list of schematics I collected in time... and I want to slowly test one by one. Just out of curiosity to see how they work / sound.
Yeah you are right sometimes simple things work better.
But if you ever decide to build a transceiver I will send you schematic included very rare mechanical filters.
good luck 🍀 and 73! 4L1LAT
@inventor2540 Please do. I always collect schematics and put them in boxes where I gather all the components slowly in time. And when there is a lot of free time, I built them when I have all the parts for each project. And thank you. 73
@@dxexplorer than we can contact
and decide how to send it and more staff
@inventor2540 Yes indeed. Send me an email when you have the time. No rush.. meanwhile I'm wishing you a fantastic weekend. 73 my friend.
I have something very simiular, ofc yt won't le me paste the link here.. Feel free to reach out. Mine also has 6 parts but it is capable of working on AM and FM accidentally (When you introduce an amplified signal on the audio+). If you're curious, I'll share the sketch that I got to work on 27MHz CB. Thanks, greetings from Hungary. :)
Ohhh that is so cool. I must try that too haha. Thank you. Yes I know is annoying with the links because of too much spam so TH-cam is trying to keep that out of the platform. Send me an email if you have the time. yo6dxe at gmail dot com. Thank you again and greetings from Transylvania 😁 73.
Let' see if yt accepts it: pasteboard.co slash GzAmTzJYVLV1.png
@@dxexplorer Thanks man, I sent an email to you.
@I33nc3 Thank you so much. I appreciate that. I'll have a look in a little. I came out to do some shopping 😅😅. Have an amazing weekend. We keep in touch.
@@dxexplorer I sent an email to you as well, my address might have been changed since. Have an amazing weekend you too! :)
❤nice❤simple❤cute
If I have time this week I will build a version in a very vintage style.. same transmitter, different look 😁
NO, No, No!!! no 700 mW!!
I like 2n3904, but this power => 0.4 W max.!
For more power you need (to) take 2SC5706 or 2SC5707 transistor.
(sorry for my english).
You can get 700mW too but you have to select the tranzistors that have a high amplification factors. At least that is what I noticed. Still... at 700mW the transistor is heating up a little but still works ok. I would also use a better transistor as you say if I would plan to use it a lot and for a long period of time doing continuous QSO's. But I wanted to keep the design original as I found it online to do a test and see how it performs. It is a nice little transmitter and really simple... I like it. No worries about the English... is not my first language either 😁😁. 73, YO6DXE
@@dxexplorer I think you have error in your powerMeter. You can`t to cheat DataSheet.
I don't read data sheets... I just play with components. The power meter is ok... I verified it with other power meter to do the calibration. You can get nearly 1W from a Pixie with a 2N2222 as PA transistor... well picked you get 700mW no problem at all.
@@dxexplorer 2N2219 = 0,8W
@phitrow In theory yes.... but as an example, you can have let's say 2 x 2N2222 but with different amplification factors. One will give you 300mW... the other 900mW... same transistor, same datasheet but diferent results in practice. I have a feeling that it depends a lot on the manufacturer too. Older transistors seem to offer me better results... the new ones made today... not so much. That is also the reason I either use "new" old parts... or simply recovered parts from older equipment )).
I would love to see this in a ‘keychain’. Like a tiny secret radio. I know it’s been done. But be nice to have a little secret agent kit. Or even buy it already made. Thanks! de n5vwn
I remember the one you are talking about. Yeah haha I also thought it could fit well into some tiny enclosure. I hate SMD components... but I wanted to try that with the Pititico II since is a transceiver, this way we could both send and receive as well. I'm pretty sure it could be possible. 73, YO6DXE.
@@dxexplorer a guy from California was selling them on Etsy. Kind of like eBay. I urge him to make more but he said they were a pain to make. His channel there was called ‘quirky qrp’
Looks fun. N9EGT
It is indeed, but I think I will have to double check the simple LPF on the output as I beleive it may not do such a good job compared to what the computer simulation showed ( as I expected ). But I don't have a tinySA to measure at this time to make adjustments. But it works really nice and I love the simplicity. 73, YO6DXE