Michigan Mighty Mite QRP CW Transmitter

Michigan Mighty Mite is a QRP CW transmitter that’s easy to built, with a rated power from 200mW to 800mW.
73, YO6DXE
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[@mktwatcher]

Very nice build and video. The Tone is very good. BTW, you Blog Site is Excellent Quality.

[@dxexplorer]

Thank you so much. I am still working on the blog to bring it up to date... but my free time is not my friend lately so it will take me a little 😁. Thank you for watching. I love the tone as well. 73, YO6DXE

[@pd1jdw630]

Looks very nice, also sounds very stable. It’s not very chirpy ore drifting. So it’s a good qrp transmitter. Well done buddy. 👍🏻

[@dxexplorer]

Thank you so much. Indeed I also like the result... I only have to play with a few more transistors and see if I can squeeze a little more power out of it with ought changing the design )) 73 my friend.

[@khalidtarawneh2289]

I still didnt watch the full Video but i can already say the most beautiful Michigan Mighty WOW

[@dxexplorer]

Thank you my friend. I'm glad you like it. That means you will like even more the next transmitter project )) This one its ugly comparing to that one ))) 73 and Thank you one more time.

[@4youian]

Fantastic Chip. Thank you so much for another nice build video. 73, Ian, VK7IAN

[@dxexplorer]

Thank you so much Ian. There is a list of videos coming that I was behind with from last year. I'm trying to catch up soon with all of them )) 73 my friend... and as always... thank you for everything... and thank you for watching.

[@harpmatt100]

I built my own 2 years ago.. Great 👍

[@dxexplorer]

Nice project to work on indeed. Sometimes I feel like a little kid playing with the Christmas gifts )) 73

[@techguy9023]

Try a Nand gate and crystal oscillator. 7400 or 74LS00. I worked a friend across town with just one chip. Just be sure to put filtering on the squarewave output because the second harmonic is almost as strong as the fundamental. I think the Norcal 38 Special tx used a 244 buffer as an oscillator.

[@dxexplorer]

That must be put on the do to list then 😁😁 Thank You... and Merry Christmas. 73 DE YO6DXE.

[@sleeve8651]

Seems the original called for the coil form, from a 35 mm film canister ! Not sure you can find one nowadays ? I used a breadboard to quick build mine, and connected to a 40 meter Ham Stick on a mag mount, at about 45 degrees, from the metal awning support it was attached to ! An old Drake Receiver in an adjacent room was connected thru a wireless 900 Mhz Headphone set ! Giving new meaning to, " Wireless " ! Hi ! I believe I powered it with Two 9 volt batteries in parallel ! But my transistor was a 3904 if memory serves me ? I worked Cuba from Illinois with it ! And on 40 meters ! Great fun ! Really like how you dressed yours up ! I had begun to experiment with some success using an LM 386 audio chip, to make a transceiver ! Those were the days ! Fun stuff ! 👍😉

[@dxexplorer]

It is a fun transmitter indeed. Cuba from Illinois... nice indeed. I am sad that I still didn't had the time to learn the code and use the MMM but hopefully soon. Thanks for sharing the little story... reminds me of the days when everything was simple and people happy enjoying the moment. 73, YO6DXE.

[@sleeve8651]

@@dxexplorer I encourage you to learn the Code ! It opens up another avenue of Amateur Radio, and I think serves as a filter to what we sadly hear, especially from American Amateurs ! Too, I guess it is like learning another language, but a truly Universal one, in that Amateurs from all corners of the world, speak it ! As to the, " MMM ", I still remember the feeling, sitting at the kitchen table with a portable shortwave radio, and hearing the oscillation coming thru for the first time ! Great Fun, indeed ! And yes, as to the time, it was a very different World ! I'm guessing somewhere late 80's, early 90's I played with it ! Funny, I had the schematic for years prior, and then one day decided to try and build one ! Quite exciting to send out a signal, never knowing where your weak signal is being received ! Great Fun indeed ! Good luck with the Code learning ! Stick with it, and don't be too hard on yourself ! You'll get it ! Just stay with it ! And thanks for your post ! '73 ! 👍😉

[@dxexplorer]

@sleeve8651 thank you so much. Ohh the code is why I got into the hobby in the first place, because I like the simplicity of the equipment you need for CW. A simple transmitter and a simple receiver and you are on air. I also had the schematic for a long time until I decided to build it. Actually there are many more on the list but I think life is too short to build them all hahaha. Is nice that it brings back good memories.

[@Radionut63]

Pure awesomeness!

[@dxexplorer]

Hehehe... thanks so much Darell. We need to catch up one of these days. And I also have to catch up with your videos as I was not so much on KZbin lately. 73 buddy

[@F8FCA]

Awesome ! Thanks 73

[@dxexplorer]

Thank you for watching ) 73 my friend.

[@multilecful]

Ciprian I have another challenge for you, the chips have arrived and some will be sent to you my friend. I am totally loving the wood look of your latest builds

[@dxexplorer]

Thought to thought ))) I wanted to message you yesterday, but I fell asleep haha. Time difference. About the wood... I have to admit, the wooden choppboards seem to be an amazing material for simple constructions. You will love the next video I think ))) I'll message you a little later today... on my way to my sister's today. 73 my friend. Ohh I forgot... I must put to use those MPF102's you sent me in the coming videos ). I'm just finishing the videos first that I had on the list last year and didn't got the chance to make them.

[@WPF465B]

Well done, thank you.

[@dxexplorer]

Thank you Michael. 73

[@okhamradio]

Thanks for sharing bro 😎

[@dxexplorer]

Thank you for watching.... as always. I have lots of fun building all thee projects, especially now in the cold winter days )) 73 my friend.

[@sv2tcb]

Very nice compact and very well presented. The problem I am facing is that the sputnik is not working 😃 again. I don't know, after the end of the summer I couldn't hear anything only some strong stations the cw or ssb was completely gone. I probably have to start building pcbs because my radio is completely a mess if you flip it upside down and I can not spot the mistake

[@dxexplorer]

Hahahaha... you are funny. Yes I know what you mean. If you remember my first testing versions used to look the same and after so many modifications I've always ended up having issues or the receiver not working. The check the potentiometer from the RF gain or the Regen one. But from what you are saying you can still hear something but not much. Maybe it's the RF gain one and you only hear the strong stations now. I had that issue too at some point as I was using the cheap ones that never worked properly )) 73 Nikos and as always thank you for watching and the nice words.

[@sv2tcb]

@@dxexplorer I don't have a proper drill to make the small holes for the pcb. I have to try making one pcb I have seen these compact projects and I cannot wait

[@dxexplorer]

I don't have one either... I really need to get a proper drillbit as well. For now my holes are also huge hahaha.

[@hendrikmetz3905]

Very nice video :)

[@dxexplorer]

Thank you my friend. As always ) 73

[@StephenCooteNZ]

Nice. Thanks for sharing. Best wishes from New Zealand. ZL3ABX

[@dxexplorer]

Thank you as well for watching. Best wishes back to you all the way from Transylvania 😁 73, YO6DXE.

[@marknesselhaus4376]

I have used the MMM design years ago and made plenty of contacts with it. Well worth building and trying out. Getting ready to put a new one on the air soon on 40M. My receiver is a very basic crystal radio design with a loose coupled local oscillator vfo ( DC) and a few filtered audio stages and it receives 40M cw from Maine to Florida here in North Carolina. 73 de WA4JAT

[@dxexplorer]

That sounds like a really nice setup. I dont have the time now and still learning the code.... very slow because of the little free time I have. But this coming winter I plan the do a nice old school combo with a transmitter and a receiver to play with and see how far I can get with as little power as possible. 73, YO6DXE.

[@marknesselhaus4376]

@@dxexplorer Hope you do not mind but I did send you a email with a pic of the receiver I am working on as well as the parts from my old MMM 🙂

[@dxexplorer]

@@marknesselhaus4376 I don't mind at all. I got it )) I will get back to you a bit later when I get home. I want to send you a photo as well. 73

[@EC5ABG]

Gran trabajo y muy bueno!!!, 73, de Tony.

[@dxexplorer]

Gracias Tony. Me gusta mucho construir todos estos proyectos. No puedo esperar a obtener mi distintivo de llamada para poder usarlos también jajaja. 73 mi amigo.

[@EC5ABG]

@@dxexplorer ánimo todo llegará, que con los trabajos que realizas vas a tener montones de DX, Así se disfruta dos veces, construyendo y saliendo al aires. Un abrazo.

[@dxexplorer]

Muy cierto amigo. No puedo esperar ese momento. Hasta entonces me divierto construyendo. Gracias una vez más. Saludos desde Transilvania.

[@G4KDXlive]

Nice PCB !😊

[@dxexplorer]

Thank you 😁 handmade... with marker 😁😁

[@indrajitR]

EXcellent

[@dxexplorer]

Thank you.. 73

[@sv2tcb]

The bd139 might needed more volts. In the past for example the bd was used for small but powerful transmitters for the am band and also there are circuits which allows the transmitter to operate in the fm band..

[@dxexplorer]

I thought of lowering the value of the 10k resistor a little maybe that may increase the power a little with the BD139. But then I tested that particular transistor on my 49'er QRP CW kit that usually gives me about 1.5W also with a BD139 as final. But with this particular one I only get about 400mW. For sure it's nothing but some cheap copy. I don't bother anymore )) I have to order a few more... but for sure not from the same store as most of the stuff I got from that place was bad quality. That's also where I got those old horrible potentiometers I used first in the Sputik and they ended up in trash a day later )))

[@sv2tcb]

@@dxexplorer I see. The 2n2222 transiator is actually the hero. This transistor output is really unbelievable.

[@dxexplorer]

Ohh yes. I'm still stunned that with a 2N2222 I'm getting 1W out of the Pititico Transceiver ))

[@sv2tcb]

@@dxexplorer probably it would be my first pcb project but I want some help. I can't find a toroid. Also in which paper do I have to print the schematic for pcb;

[@dxexplorer]

@@sv2tcb Here you have the link to the latest version I built: tinyurl.com/sputnik40-rx For the coil.... if you can't find a toroid.... no problem I will email you the details for the PCV pipe version. Works just as good.

[@stewpot3971]

Nice transmitter! Did you get your license yet? I remember on one of your videos last year that you were still waiting to take your exam (and this was delayed due to the current global pandemic). Hope to work you one day and 73 from the U.K.

[@dxexplorer]

Thanks so much Stew... no not yet. After I finished helping my buddy with the pigeons this summer... I ended up leaving to Italy... by the time I got back they were asking for the "magic certificate" to go and attend the exam. I don't plan on getting such certificate so for now I'm waiting for the waters to calm down then I'll go get my license )) I'll let everyone know for sure as soon as I get my call sign. Cheers and 73.

[@stewpot3971]

@@dxexplorer certificate free here as well😉😉 there might be an option to take your US/UK license (both can be done online) up to Extra/Full and then 'convert it' to a Romanian license? I know that the US hams get the chant to take their technician/general at the same time...just a thought 😉

[@dxexplorer]

I know... I've heard the news and I was really happy about it. I hope they will end up with all that in here as well.

[@dxexplorer]

Ohhh by the way... not a bad idea about the license. I must look into that. Thank you for the idea. I think it could work... plus that I would be happy to have a US call sign as well since I will return in Miami next year aboard my sailboat. Thanks for the idea )

[@josephhager1933]

Nice work it looks good where did you get your watt meter from ?

[@dxexplorer]

Thank you so much Joseph. The look of the transmitter was inspired from another one that I'm about to build and I will talk about in a future video. The watt meter I built my self. Not yet finished yet. Video coming soon about that as well. I have two scales: one from 0 to 1W, another one from 0 to 10W. More than enough for the QRP stuff I'm building. The meter itself it's actually a cheap Chinese meter to measure uA. I just removed all the extra parts and just kept the necesarry. I'll make a video soon and describe the entire circuit in detail and how I calibrate the entire thing. 73 and have a wonderful weekend.

[@2222MalayalamElectronics]

Very nice, is that large air core coil for low pass filter? like these old time stuff (Pixies) and regens for their high performance-simplicity ratio.

[@dxexplorer]

Thank you. The big coil is the transformer basically that it's coupling the output of the transmitter to the antenna. Impedance matching transformer I believe. The low pass filter its made with the two little toroids made on T37/2 and the necesarry capacitors. 73 my friend. Glad you like it

[@johnkemas7344]

Is your tap for the LED red indicator drawing down your power output?? That tap has to absorb a certain amount of energy also. Try it with out it and see what your power output is.

[@dxexplorer]

Noooo... that has nothing to do with the output power. Its the same with or with ought it. Its all about the transistor used and the amplification factor of the transistor... also I think the current the crystal can take also has an influence on the power output.

[@johnkemas7344]

@@dxexplorer Thanks for the update!

[@dxexplorer]

@@johnkemas7344 Always a pleasure. 73

[@edb.793]

Use the BD139 for the 2nd stage, a MOPA??

[@dxexplorer]

Maybe for a later one ) I wanted to have one sticking to the original schematic. I have seen a few modifications online that I want to try later on.... but for now I will leave this one as it is.... as a memory )) 73 my friend.

[@bobi_lopataru]

Does the wire thickness for the coil matter or can we use any thickness? (I only have 0.4mm wire)

[@dxexplorer]

It does matter yes. I used 0.7mm if I remember. You can use 0.4mm too... but you will have to recalculate the number of turns to give you the same inductance as the original coil has. I'm using coil32 app to calculate the coils.

[@bobi_lopataru]

@@dxexplorer Ok, thank you, it seems that almost all the inductance calculators don't care about wire thickness or even lack the option to specify the thickness.

[@bobi_lopataru]

@@dxexplorer ok I just checked, I also use coil32 online toroid calculator, but changing wire thickness doesn't appear to change the inductance at all

[@dxexplorer]

Hmmmm that's strange. I also use the same app and the inductance is changing dramatically if I change the wire thikness. I'll see in the morning if I have a little time and I will calculate and send you the coil details for the 0.4mm wire you have.

[@Saltboi231]

I love your video series on the Sputnik. Could you do another build that can receive voice communications? I don't really like Morse, but I am a fan of homebrew receivers that can pick up people talking. Thanks! :)

[@dxexplorer]

Hahaha... thanks Paul. You mean like SSB coms ? I'm showing mostly CW in the videos because that was the hard part of making the receiver working well with those... but you can also receive SSB with the Sputnik. I listen a lot when I have the chance to be at home and the receiver is always on. Basically all versions of the receiver I built so far, are covering the 40m ham radio band from 7.000MHz up to 7.200MHz. So that covers both the CW part of the band... as well as SSB. I will return with the Sputnik and a few more receivers a little later for other bands too though. 73 buddy.

[@soldadodecristo9254]

hola consulta cuanto costaría el kit del transmisor armado y probado para enviarlo a chile

[@dxexplorer]

Amigo... por el momento no tengo tiempo libre para hacer kits. No sé cuánto costaría para ser honesto... pero es muy fácil de construir con muy pocas piezas. Con el dinero que gastarías en servicios postales... puedes comprar piezas para construir 4 transmisores no uno ))). Dime qué información necesitas y te ayudo a construirla.

[@MrtechElectronics]

Bro i liked this video. I want to built a QRP Tx but i don't have 7.03 MHz crystal can you build a Tx without crystal

[@okhamradio]

It will be not stable on frequency

[@MrtechElectronics]

@@okhamradio yes you are right

[@dxexplorer]

Yes you can... but as Oleg mentioned.... it will not be as stable. Try to find a crystal for the 40m band.... it doesn't have to be 7030MHz. The ones used in the Pixie are easy to find.... 7023MHz. I use 7030MHz just because I had a few of them knowing that it's the QRP calling frequency. If not you can also build it for other bands too. I would try this one instead.... you get a little more power out of it: kzbin.info/www/bejne/mWeoh2l7hLlqfpI If you still want to build the Michigan Mighty Mite for a different band that you may have a crystal for.... let me know and I will send you a link to the article where you can find more details about the coil for different bands. 73 buddy.

[@lisaniotag]

Can I ask, what is its effective range?

[@dxexplorer]

Same as the 10 minutes transmitter. I left you a reply to the comment there. 73, YO6DXE.

[@adanlewis7489]

How did you wind the coil?

[@dxexplorer]

I did L1 first... 21 turns with a tap at 7 turns. Then on top of L1 I did L2 4 turns. L3 the one for the LED is next to L1 at about 4mm away doesn't matter on what side of L1.

[@adanlewis7489]

@dxexplorer thank you. Slowly figuring it out, will be my first coil. I will probably want to make a video tutorial how to do it for my friends. Got some folks in the Long Island cw club that are interested. Also noticed in the schematic that the 27ohm resistor is labeled R2 when I think it should be R3

[@dxexplorer]

@adanlewis7489 I am testing a version with a toroid coil instead. It seems to have a little more power output. Not by much but in QRPp evert mW matters 😁. This one sounded nice... the one in the video i mean... but I wasn't too haply about the power output. Maybe a better transistor would help too. I think the original had a 2N2219 if I am not wrong. I can't remember for sure.

[@adanlewis7489]

​@dxexplorer fabulous keep us posted. I broke my leg so I have a lot of time to play around and build some radios!

[@dxexplorer]

@adanlewis7489 Ohhh heck... sorry to hear that. Yes I hope this weekend I will have a little time to play as well and I will get back to you and let you know the results. Just in case I forget... buzz me in here or on the email and for sure I remember 😅😅. 73, YO6DXE.

[@oliverfranklypartolesen9882]

Hey friend can you Build one with microphone to use with sputnik

[@dxexplorer]

Hi Oliver... I think the Michigan Mighty Mite can be modified for AM vocal transmissions.... but I don't think I will bother with that. Instead I may have something simple with two transistors that could be used just for the fun of it. For now... I have more complicated stuff later on )) But yes I'll make a video sometime soon about what you asked. 73 my friend.

[@user-sh8nn9gx7b]

73 from baghdad de Yi1hxh rafat

[@dxexplorer]

73 my friend. Greetings from Romania.

[@SalvadorGaspar-tf6kr]

Boa tarde macanudo mandar o esquema para mi.

[@dxexplorer]

Bom dia... se você acessar meu site dxexplorer.com procure a categoria transmissores na página do blog. Você encontrará lá. Vou postar outro vídeo talvez daqui a um mês com uma versão melhor. Mas ainda tenho que fazer alguns testes antes disso. 73, YO6DXE.

[@tim46767]

1. practically every transistors are build in china. 2. made in china doesn't mean bad quality. You get what you pay for! If the market need low price, china will deliver it. 3. Lower output power doesn't mean low quality transistor. Choose a transistor with a high hFE gain. Every multimeter has a transistor hFE checker. The gain varies a lot! Thumbs up for your work. TY

[@dxexplorer]

Thanks so much Tim. Yes I agree on what you say. I think I was talking about that in the Pititico video when I was saying that the transistors I got from Radio Shack years ago work well.... and those are probably also made in China )). But the quality is indeed different comparing to the latest ones I have. I am happy that I discovered now the difference in the hFE gain as I would never think of that otherwise. I always thought all 2N2222 are the same for example. About the BD139 I was talking about.... that is a really bad quality one ( I'm suspecting is a fake )... that's just because I measured another one that I have and the difference it's too big from what I found on the datasheet. Definitely a fake or low quality one. As example... I tested it in the 49'er transceiver where I'm also using a BD139 as final that's giving me 1.5W output.... but with the "fake" one I'm only getting 150mW ))). I understand now that there is a difference in the gain.... but that much sounds a bit sketchy to me )) Thanks one more time for watching the video. 73 and now I will keep in mind to check the gain first for the future projects ))