Thanks Peter for sharing this video with us. Kostas sv3ora is preparing a new video in reply to yours about how good this transmitter could actually sound. So wait for his video. Regards
Fantastic! I find these rigs so much more interesting and fun than a modern digital fully featured rig. Amateur radio is about having fun and learning, and toying with simple circuits like this and experimenting with different parts like crystals shown here gets me going. Thanks for another awesome video Peter!
if you ever need a transmitter to quickly send a message this would be it, as long as you can send a message and get done what needs done it doesn't really matter much about the tone because its still transmitting code and that code is words nice video mate
Once I made a “dub siren” analogue synth. The sine wave was constant but when I breathed warm air (like you want to warm your palms on a cold day) onto the circuit, it changed pitch! I searched and found that when the humid warm air hit one of the capacitors this changed the pitch! I wonder if it’s not the same source of instability in your circuit as well, try blowing warm air onto the capacitors to see! Cheers and thanks! PS I want to build your other circuit with the inductors 😀
I built this QRP and I liked it, it's very good, I want to know if it's possible to transform this fixed oscillator into a VXO, it would be cool if I could change the frequency, I'm a radio amateur my call sign is PY5LG Brasil
I love seeing variations of the Michigan Mighty Mite. They're so deceptively simple (iirc most version of the mighty mite use 2n2222 since it's plentiful and will work up to 40m).
This is NOT a variation of the Michigan Mighty Mite. The only common thing is that both are self-exited power oscillators. The Emergency Transmitter by sv3ora uses a capacitive divider in the feedback path and then the crystal is connected to it. That is totally different of the Michigan Mighty Mite, which by the way, can't provide 10W of output power like the EMTX does.
I built one of those on a toilet paper tube for code practice many moons ago, except used a variable capacitor instead of a crystal. Needless to say it wasn't all that frequency stable.
Of course! Without a crystal in the feedback path, what kind of stability would you expect about any power oscillator? Peter hasn't built it properly too, that is why chirp suffers. If you build it properly as described in the page qrp.gr/emtx and if you parallel more hc-49u crystals or use vintage ft-243 ones, you will barely notice any chirp even at 10W of output power that this transmitter is capable of! I've built that already and I know what I am telling you.
I've done some low power AM videos. Eg th-cam.com/video/Wgj22ZU63KY/w-d-xo.html But for more range you should have at least 3 transistors in the RF section and properly modulate the power amplifier stage with a good audio amplifier.
Peter Can you please do areal good indepth video of making and using a homebrew “ Michigan Mighty Mite & Subsequent Mated Receiver “ ? I’d LOVE to see that as I have had many thoughts on constructing one but are too scared ! All The Best From “ Bonnie Scotland “ U.K. 72’s 73’s Andy The City Of Stirling Central Scotland
I wonder of this could be converted into a transceiver by have the transistor double as a regenerative detector? Maybe controlling the base current for transmit as well as a regen control. Just a thought. Cheers, Ian
I have tried that but didn't succeed. I couldn't make the thing oscillate at low power, it always started from about 4W and upwards with the transistor used in the EMTX article.
Hi Peter, just wondering how you measured that the outgoing coil (2 turns in your version) has 50 ohm impedance? Have you used SWR meter to check with how many turns the PA is matched to the antenna? Or is it some other way/calculation you did? I did 2 transistor QRPp cw transmitter but don't know how to verify the output is 50 ohm. Also, would help here to use 78L12 to stability of this one-transistor transmitter? I didn't check what is max V this BD139 can handle, but I imagine with higher V e.g. 24V we can draw even more power?
Where the power is low you really don't care much about SWR and matching although it will still improve performance. Seems to me that keying the emitter is going to introduce some dynamic impedance changes anyway.
Would you be interested making a video of making and testing this transmitter? sparkbangbuzz.com/easy-ten/easy-ten.htm It is supposted to have a range of about 15KM and it is very simple. If you want you can try different transistors and you can even try to add some amplifier stage to it, its a simple transmitter with no handwind coils. I would be really happy if you would try it and made a video about it.
Have you tried building anything like this? The Gnat 1: A One-Transistor CW Transceiver for HF Frequencies www.home.earthlink.net/~christrask/Gnat%2040.pdf Extra info on coils, here:- www.qrp.gr/ultimateqrp/index.htm
I built this QRP and I liked it, it's very good, I want to know if it's possible to transform this fixed oscillator into a VXO, it would be cool if I could change the frequency, I'm a radio amateur my call sign is PY5LG Brasil
Love these long distance, one transistor projects. I have one I’ve been working on, 28mhz, 250mw CW. I’ll have to send you a PM. 73s - k0mov - Saint Louis MO USA
Fun project ... and glad the KiwiSDR here came in useful. VK2AAK.
Thanks for your KIWISDR, I use it for similar testing and general listening. Paul VK3HN.
Ditto! Love ur SDR!!! Thanks for sharing!! VK2AOE
Thanks Peter for sharing this video with us. Kostas sv3ora is preparing a new video in reply to yours about how good this transmitter could actually sound. So wait for his video. Regards
Fantastic! I find these rigs so much more interesting and fun than a modern digital fully featured rig. Amateur radio is about having fun and learning, and toying with simple circuits like this and experimenting with different parts like crystals shown here gets me going. Thanks for another awesome video Peter!
I had not really thought about using web based SDRs before for experimenting, thanks for the idea.
Love the simplicity of this and may well have a go at building one. Thanks for your work in making these videos.
if you ever need a transmitter to quickly send a message this would be it, as long as you can send a message and get done what needs done it doesn't really matter much about the tone because its still transmitting code and that code is words
nice video mate
Once I made a “dub siren” analogue synth. The sine wave was constant but when I breathed warm air (like you want to warm your palms on a cold day) onto the circuit, it changed pitch! I searched and found that when the humid warm air hit one of the capacitors this changed the pitch! I wonder if it’s not the same source of instability in your circuit as well, try blowing warm air onto the capacitors to see! Cheers and thanks! PS I want to build your other circuit with the inductors 😀
I built this QRP and I liked it, it's very good, I want to know if it's possible to transform this fixed oscillator into a VXO, it would be cool if I could change the frequency, I'm a radio amateur my call sign is PY5LG Brasil
I love seeing variations of the Michigan Mighty Mite. They're so deceptively simple (iirc most version of the mighty mite use 2n2222 since it's plentiful and will work up to 40m).
This is NOT a variation of the Michigan Mighty Mite. The only common thing is that both are self-exited power oscillators. The Emergency Transmitter by sv3ora uses a capacitive divider in the feedback path and then the crystal is connected to it. That is totally different of the Michigan Mighty Mite, which by the way, can't provide 10W of output power like the EMTX does.
I built one of those on a toilet paper tube for code practice many moons ago, except used a variable capacitor instead of a crystal. Needless to say it wasn't all that frequency stable.
Of course! Without a crystal in the feedback path, what kind of stability would you expect about any power oscillator? Peter hasn't built it properly too, that is why chirp suffers. If you build it properly as described in the page qrp.gr/emtx and if you parallel more hc-49u crystals or use vintage ft-243 ones, you will barely notice any chirp even at 10W of output power that this transmitter is capable of! I've built that already and I know what I am telling you.
This is supercool.
Can it be modified to use as a music transmitter for the mediumwave band ?
I've done some low power AM videos. Eg th-cam.com/video/Wgj22ZU63KY/w-d-xo.html But for more range you should have at least 3 transistors in the RF section and properly modulate the power amplifier stage with a good audio amplifier.
Excellent Peter ... Dave, G4AKC
Make it a MOPA, one transistor as the a low current osc driving a BD139 would be cool too
Peter
Can you please do areal good indepth video of making and using a homebrew
“ Michigan Mighty Mite & Subsequent Mated Receiver “ ?
I’d LOVE to see that as I have had many thoughts on constructing one but are too scared !
All The Best From “ Bonnie Scotland “ U.K.
72’s 73’s
Andy
The City Of Stirling
Central
Scotland
Do you think this would be stable enough for a beacon?
No.
No.
I wonder of this could be converted into a transceiver by have the transistor double as a regenerative detector? Maybe controlling the base current for transmit as well as a regen control. Just a thought. Cheers, Ian
I have tried that but didn't succeed. I couldn't make the thing oscillate at low power, it always started from about 4W and upwards with the transistor used in the EMTX article.
Hi Peter, just wondering how you measured that the outgoing coil (2 turns in your version) has 50 ohm impedance? Have you used SWR meter to check with how many turns the PA is matched to the antenna? Or is it some other way/calculation you did? I did 2 transistor QRPp cw transmitter but don't know how to verify the output is 50 ohm. Also, would help here to use 78L12 to stability of this one-transistor transmitter? I didn't check what is max V this BD139 can handle, but I imagine with higher V e.g. 24V we can draw even more power?
You're over-thinking things. Just build it and use it. Make changes to optimise its output. If it blows up then you've done something wrong!
Where the power is low you really don't care much about SWR and matching although it will still improve performance. Seems to me that keying the emitter is going to introduce some dynamic impedance changes anyway.
Would you be interested making a video of making and testing this transmitter? sparkbangbuzz.com/easy-ten/easy-ten.htm It is supposted to have a range of about 15KM and it is very simple. If you want you can try different transistors and you can even try to add some amplifier stage to it, its a simple transmitter with no handwind coils. I would be really happy if you would try it and made a video about it.
Good project, 10 miles range is amazing
Hi Peter what kind of antenna did you have it connected to?
G5RV
Have you tried building anything like this? The Gnat 1: A One-Transistor CW
Transceiver for HF Frequencies
www.home.earthlink.net/~christrask/Gnat%2040.pdf
Extra info on coils, here:- www.qrp.gr/ultimateqrp/index.htm
Could the air core be subbed for a toroid?
Yes.
@@vk3ye would the ratios remain the same? I imagine I would have to re-figure the resonance for the big coil.
@@kq6up Yes. There'd be a fair bit of fiddling around.
can it be used as Fm transmitter with mods
No. Better to use a dedicated VHF circuit. Many bug circuits on the web eg on the Talking Electronics site.
@@vk3ye ok.thank you.love all your work with minimalistic designs
I built this QRP and I liked it, it's very good, I want to know if it's possible to transform this fixed oscillator into a VXO, it would be cool if I could change the frequency, I'm a radio amateur my call sign is PY5LG Brasil
Love these long distance, one transistor projects. I have one I’ve been working on, 28mhz, 250mw CW. I’ll have to send you a PM. 73s - k0mov - Saint Louis MO USA
2 menny parts kg6mn
To cagando e andando para este Gringo...
Very simple and very effective Peter.☺73..G7HFS/PA3IKH
I don't think I would like to put this one on the air
Build it properly as described in qrp.gr/emtx and then you might change your mind.