Ham Radio - Build your own QRPp CW transmitter
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- čas přidán 26. 03. 2017
- I build up a very low power crystal controlled CW transmitter and make a contact with it.
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W9TE (Node: 519521) - Věda a technologie
One of the ideas that went well at a local club that I suggested was called Desert Island Radio. Small groups were given a small pile of components and a few hand tools and the challenge was to build an 80metre transmitter. Some suggestions were put on a chalkboard, and the idea was the first team that could be heard on a receiver at the front of the hall. Included was a common QRP crystal. I think the record was somewhere between 10&15 minutes. A couple of times we ran this competition some even managed a transceiver.
Hey, that's a great activity! Brought up a memory of high school electronics class and a monthly similar competition the teacher gave us. Here's a pile of components, make a thing that does this.
Cool! Must have been fun
Blackboard, not chalkboard, we don't say penboard,we say whiteboard
Great video! I would like to suggest that mounting a plug for the crystal instead of the crystal itself to the board will allow you to change crystals and work different frequencies. That's how we did it back in the day. ;)
Would it be possible to install a tap and multiple crystals?
Another way is to use a trimmer in series with crystal to vary the frequency, say, up to 0.5 kHz the actual base value.
5 MHz????? You're suggesting a trimmer could push a 3.5MHz crystal up to and beyond the 40 meter band? Uh, nope.
A trimmer can bend the crystal frequency maybe a few hundred Hz.
@@loughkb O o! My apologies! I mis-typed it. You are correct! If it is 5 MHz, it can take it close to 5.0002 MHz which I believe is a fair range of variation, don't you think?
@@awaismushtaq5719 Yes, with a large enough trimmer you could push it that far. You start to lose stability the further you push it though. Caps vary with temperature and other factors.
Just a tech, but I understand 80 percent of this, have a great time studying and learning the rest. My wife watched a bit, thinks you're a NASA tech building something for a moon rocket. She still doesn't believe that some of us actually do work on and work satellites.
Linus:" I can build PC's"
This dude:" hold my altoids tin"
I love linus
What the :::::? So?
Heh! Good job, Kevin. Surprised to see a wooden key. I'm doing one of those myself for laughs. I'm in the middle of a 807 tube tx for 40 with a 6AG7 oscillator. No smoke yet, so wish me luck. Thanks for the vid. We need more stuff like this for kids and frustrated new hams....
From Detroit, I made a 600+ mile QSO on 40m, with 200mw output. I got a RST 339, but it was quite cool making a contact with two 2N3904s and about ten other components, including the filter. Anyone trying QRPp or QRPe should know that SWR and coax loss are major factors. I used good quality RG6 and a dipole tuned for the CW end of 40m. I made contacts to Connecticut and Wisconsin, too. The Kansas QSO was about 2 hrs after sunset and the other two were midday.
I enjoy your Videos how do I make this operate on 20 meters. I have many 20 meter xtals ... what would you change about the Torids?
Nice build video Kevin. I picked up more information about circuitry during explanation of the schematic. Certain people in a persons make an impression on one''s learning process. That circuit has been explained to me many times before and it didn't click in my brain why. Your explanation helped. Still learning at 70.
Yep back in the day we would saddle are dinosaurs and go foraging for vacuum tubes to build transmitters ; )
And when we said rockbound, we meant ROCK bound. (My elmers were Fred and Barney.)
Yeah....back in my day we would scratch the crystal with the cat's whisker and listen for the station signal.....the tuning coil was wound on a toilet roll tube.....too high tech to get a variable capacitor.
CD S omg I miss those days....
Ahhhhh, Hello Kevin, today I sit once again rewatching this awesome video. However, I must add,,,, I popped into the Living room and switched on the wide screen Tv and sent this video to our Apple TV box. Coffee stationed to my right and toast stationed to my left. This is my preferred method now to enjoy watching your videos. I really like the schematic here. Very clear, certainly large enough to see the components and well lit. Way to go on the teaching as well. 73's Kf2ms
You may have seen my video on the small HP computer I found in the trash up the street. A small device, intended to be used as a terminal 'client' computer for kiosks and such. I loaded linux on it and connected it to my TV with a wireless keyboard and mouse. Since it's a full desktop OS, I can watch all the videos, even those slated as not viewable on tv set top boxes. I don't know if you've run into that on youtube or not.
So, I guess you enjoy "armchair copy" then. :-)
Kevin, really nice and educational video. It revisits the idea of how we used to make xmtrs and rcvrs many years ago. Thanks for reminding us it still possible to do cheaply and effectively even in days of smd electronics.
Re drilling thin metal, use a step drill .Works a treat. Excellent video.
Nice job. Thanks for making the video and I especially like that you actually made a contact with it. Keep up the good work, and CU ON CW!
Very nice. Loved watching this. Thanks for the detailed explanation too.
Great video Kevin, it makes me want to brush up on my CW and give it a try, (again!).
What an outstanding video! Very nicely done, I really enjoyed this. I'm a noob to circuitry so it was still a little quick for me at my level, but still very very good. Thank you.
Yes Colpitts oscillator....I always remember because it starts with a C! For tapped capacitor.
Hey Kevin.. This was just recommended for me to watch on YT home page! They've not forgotten you!
And that's an old video too. I hope to be better and back to doing videos in a month or two, we'll see. Long covid sucks
I have an original Rockmite to finish, just need to install the “upgraded final” and mount it in a pin Altoids tin that has been earmarked for this since 2003 (or maybe 2005). Great project, great video, thanks for posting. 73s N1XF
at one minute you said plethora the same way I do. ple Thor ah. also the transmitter looks amazingly like a pixie two. great job in making the enclosure and all that other stuff. it's the last steps that make it into a complete project. great job!
Pinatas???
Nice job on the mini 2 stage transmitter. Nice timely QSO. Can't beat that. And, apparently only one Altoids tin to complete the job !! Now you just need a crystal socket on the board and you are set. You could even use it, if you had a frequency counter, to check crystals for operation and frequency (at least crystals in the 40 meter band). lol 5 *
Wow! Great video, lots of dedicated work, very interesting and informative. You da Ham man!!
Wow ! Very interesting project. I would love to know more about it !!!!!
to me THIS is ham radio. diy minimalistic rig , then see how far it goes and how to optimize or add to it. thanks for the demo! 73!
perfect starter project. Thanks! Earned another sub :)
Very clean CW, sir.
Thanks. When learning, I spent a lot of time working on the spacing. I want to speak clearly ;-)
And speak clearly you do. Did you use the Farnsworth Method while learning?
Thanks very much for showing how you use the breadboard to put together this circuit. I have numerous altoid projects and enjoy my pixie. N9egt
To: KB9RLW / Kevin Loughin, You can know that one of the rarest bits of information about Ham Radio that I One of the things I struggled to find, is just something simple and basic for a beginner and Technician. That is for someone to tell me a good band and frequency to use for transmitting and receiving with slow CW. Well, you just gave it to me. Although people working to teach others are helpful in their own way, sometimes they offer more than a few general suggestions all at once, rather than just TELLING the new ham something specific. Usually, when beginners ask, they get all kinds of evasive answers or odd answers, or just too many answers all at once, as a kind of rhetorical response. As a beginner, all I really wanted was for someone to suggest to me, a project, or a frequency / band to operate on as a primary focus to initiate my learning. Here is what I just got from you.
CRYSTALS for the CW bands on 40 meters... good for SLOW CW are
crystals in the 7.05 to 7.055 range or 7.1 to 7.122 Mhz...etc.
You one smart fella. Whether intentional or not, you seem to adopt the KISS PRINCIPLE into your messages.
(You know....Keep It Simple Stupid....)
Bless your little pea-pickin' heart. I really like what you do! KNFNNT
Thanks Bruce, I'm glad you found it helpful. That's my goal, just get the needed info out there in a clear way. I spent years working help-desk in I.T. So I learned how to break things down to make them understandable.
Try SKCC (Straight Key Century Club) and/or FISTS. Great places for beginners in CW. An Elmer pointed me that way and, so far, so good. He also mentioned that the "50s" of bands are usually typically you can find beginners. .050 of a band.
Did anyone else have a little nerdgasm when the contact was made? This vid was so much fun - tnx :)
Nice job ........... great explanations ....... love those radio hams ............
Thank you. Very good presentation.
Good to watch this, I learned a lot.
Awesome!!! Definitely inspiring me to build one.
Fascinating and informative. Thank you.
Love this video thank you for sharing the knowledge
Hi it is great to see hams doing design & construction projects. It seems like there only cb rs are the only ones joining the ranks any more, those that have no electronics knowledge nor do they want any. Again, great video!
Nice rig, gud DX OM 73 de KT1R (still loads of snow up here in Maine, ugh!) (as of March 27)
“T-hotally spaced out Doode!” 👍👍
There is a few things I noted.
The output amplifier is very heavily coupled to the oscillator. I would reduce its value to 220pf and see if the output changes much. If it doesn't, then its better as you have reduced loading on the oscillator. Also the output PA circuit would be better matched to the output LPF by using a coupling transformer. A small 4:1 transformer wound on your toroid would improve things. The collector of that PA would have a very high impedance compared to the 50 ohm load.
In fact if your PA was only producing 500mW (and it's not) you'd be looking at a collector impedance of around 140 ohms impedance if your power supply is 12V.
At 200mW it would be 360 ohms.
If you were getting 350mW, it would be 200 ohms and a 4:1 balun would give you the best power transfer.
The input impedance for first transistor is too low and crystal is definitely being loaded to cause probable frequency shift. He ought to have used voltage divider bias. That way he could increase the input impedance to at least 500 k-ohm. Besides base bias isn't a very stable and promising biasing method. He could have used 1 k-ohm in collector of first transistor and could have connected 100 k-ohm in parallel to collector resistor for improved performance and reduced crystal loading. Another way might have been to put crystal in parallel to at least 100 k-ohm resistor and throw oscillation at the base for due gain. Anyway, his transmitter, his design!
He could have added a variable capacitor of 100 to 120 pF in series with crystal for better feedback control. Mr. Dazzwidd is right in his analysis. Also, adjusting Colpitts tank capacitors to 220 pF could have been much better. It's true that design needs improvement. Moreover, 2N2222 is a bad choice for oscillator and for overall RF design. The 2N4265 would have worked loads better as its transition frequency is 300 MHz which is way higher than 7.023 MHz used here.
If you know better why are they watching this video ? Experts.!
Nice to see you don’t have to send Morse at a million letters a second.i could actually work out the words !
Great video Kevin! For those unable to send in morse code, wondering what would be needed to connect this up to a Raspberry Pi and run morse code software
You don't need Pi, you can do it with Arduino as well!
Excellent video. Subbed.
Great video. Sorry it too me so long to find it. Blessings.
Mr Kevin sir, it's a good practice to use two reverse and forward connected diode pair to avoid transistor saturation and over voltage burning in case extra voltage dropped in.
Thank you for this video.
I think its a very worthty explanation video. I examples how in history radio's were build.
For my lectures as a teacher in physiisI do have a few questions:
1) does the frequenty of the crystal set the transmissionfrequenty?
2) if I would replace the amplifing transistor with a transistor with a highr power, would the power of this transmitter be bigger?
3) In the stores I can bey electral components like resistors, condensators and Inductors; are those premade Inductors also usable, or do I have to make the inductors myself?
Again, thank you for making this video.
I built this. It does well for one watt from 2 transistors. N9egt
cool getting contacts with it👍😎🇬🇧
very impressive, OM.... tnx for the demo.... ur gud fist...... 73s..... from Bill, KE1LC
Kevin
I find that hot gluing an old gift card fits just right in the bottom of the tin.
For the holes I use a 1/8th drill bit then a reamer.
Great channel, I always watch your videos.
73
wd4dda
Good ideas.
That was cool! Thank You 😊
My local bargain shop sells biscuits in nice tins for $5. Biscuits a bonus, tins great for these projects Thanks for presenting, 73's, Barry, VK2FP/AG7VC🙂
A QRP tx is so easy to make and they work. And with a simple rx, wire aerial and tuner you have a complete portable QRP station and the battery will last a long time.
G4GHB
that's wonderful! :D well done!
Good vidéo Tx QRP 72's Fab F5RLW
Altoids tin for a pixie tranciver, Altoids tin for Antenna. Altoids tin for fire starter, Altoids for beef jerky/peppermint. one more for instant tea/ coffee, and log book. It makes for a swell week end. tks for show and tell 73 de kv4li
Great video.
Very nice! I just cloned your circuit and it is very slick... tks! 73 de K7ZB K Those are T50-2 toroid cores...
excelent job ..!
You can use a 555 timer IC with different capacitor ranges instead of a crystal as well but great job!
Yes, and gain a pseudo VFO. But you would also have to add additional filtering to smooth the 555's square wave into a sine and eliminate all the harmonics. Plus there may be a stability issue or even chirp if the 555 doesn't start right on frequency. I suspect it would take a few ms to stabilize.
@@loughkb yes very true BTW love your contact with ke0og subbed to u buddy and 73! Also enjoy your videos!!!!
I have watched this one video several times, and this afternoon I came home from the Electronics store with a bag full of goodies to make the transmitter. Total cost $40. Basically I am breadboarding and using my audio generator & O-scope to check out circuits that I make. Simpler the better and you can't get any more basic than what you have shown here. I did buy some extra parts and some 10 Mhz crystals for the 30 meter band. As i bread board the circuit I will change the crystal to see if it will work on 30 meters as well as 40. I may add a band switch into the circuit... 73's de kd5smf
The oscillator may run at 10Mhz, but you'll probably have to play around with the filter circuit to raise it's threshold up to frequency.
I bought a couple of varible inductors that I can tune the circuit with at L1 & L2 (a t-8324 & d29002202) where one is wound at 10 turns and the other at 14 turns. Not sure how those will work but thats why we breadboard circuits...
+Mark let me know how it goes. Send me a pic or two of the final build, I like to post those on the Facebook page for others to enjoy.
This was great! Have you ever built or have a video about a transmitter that utilized tubes? In very interested in building my own classic transmitter.
There's lots of tube based designs out there. A quick google search for simple tube transmitter ham radio should turn up several.
I won't be doing any though. Big transformers and such take up space and I'm living in an RV that's already full of stuff. :-) Oh, and rarely plugged in to AC power. ha.
When Kevin showed the harmonic reduction due to the LPF, did I miss the value of the load resistor terminating the filter output? This value can make a BIG difference to filter performance, and therefore the harmonic level too! Also, if it's R ohm it's easy use a scope to calculate the RF power out from (Vrms^2)/R.
I would have been using my MFJ dry dummy load. It's 52.9 ohms through most of the HF spectrum.
Nice, when I get around to putting my Pixie together It might just work ;)
Mine works no problem
it's a class A amp, so efficiency will be less than 30 percent, but bc it's two stages, it will be even less like or less 0.01, so 10mW at max
I wonder if this wouldn’t work with the inductor coils just wound around a stamp of McDonald’s plastic straw and paraffined, no ferrite? Thanks for nice vid!
I just built a QRP Pixie. Wondering how much wire to coil around a broomstick for a decent antenna.
This is very informative thanks a bunch. If I wanted to make one for 10 meter band, apart from the crystal, do the values of capacitors in the first stage oscillator change and if so would it be to resonate at around 28MHZ?
Everything changes, including the low pass filter. There's several web sites for calculating those.
What is the core types and the actual uH value of the toroids please? Nice build!
Very cool.
Nice scope/analyser. Which one is it - I'm in the market for one...!
I'm having a heck of a time even with RBN "hearing me at 8/10th of a watt through a compromise antenna
I enjoyed this video. I would like to build this for 20 meters cw. What would your recommendations be concerning the torid band pass filters? What other recomendations would you have ?
Ron K5QJP
i am new to electronics and ham radio but which component would you use to change the bandwidth of a receiver? i thought i would ask you because you seem to know what you are doing
Excellent!
I would love for the FCC to bring back CW novice without voice with 3 to 4 license tiers. Yes, a kind of key club for keyers. Today's hams are only 11 meter refuges.
Hi Kevin, new subscriber here. I binged-watched all of your videos this weekend, thanks for making them! Your discussion on toroids reminded me of a question I have. I'm assembling a BITX40 transceiver and while overall build quality of the board is great, most of the toroids are wibbly-wobbly and I'm afraid the leads will break eventually. Since you've worked on lots of old radios and probably have a good idea of what works and what doesn't, what do you recommend to immobilize the toroids for the long term? Hot glue? Silicone? Something else? Thanks!
Yeah, I think either hot glue or silicon would work. I'd lean towards hot glue, and just a dab where the torroid meets the PCB.
Thanks for watching!
Any chance this design can be upgraded to include a VXO? Can you swap in a VXO for the xtal without having to swap out any other parts?
Gonna do this Manhattan style
You lost me at 0:00:01.
I was lured by the Altoids Tin. Now my brain hurts lol
Excellent
Hi Kevin -
Great video. I'm ordering parts to build the QRP TX. I enjoy your loop antenna videos too. In my HOA situation, I may need to build some.
Are both toroids 17mm? I found some on Amazon that are that size. Does the mix matter or at these frequencies, is virtually any common mix likely to be OK?
Looking forward to building this rig.
73,
John, KJ7RDV
17 mm he said for both with AWG 18 wire. Usually 17 mm is thickness of the toroid. I wonder which dimension did he mean by it
Muito bom. Parabéns. ..
Nice video. Nice transmitter, and of course, it works. Trying to figure some stuff out to operate where my employer is housing me. Something like that might just do the job. Tnx for posting. 73, KK7XE
Could you explain how you hooked up your receiver to the transmitter? Very interested in that
I have a double pole double throw switch in it. One side switches the antenna between the RX out connector and the transmitter. The other side of it switches power to the transmitter. When in RX mode, bumping the key won't transmit and hurt the receiver.
I wonder if this could be used for QRPp in the phone section of the bands. Making a low power TX radio for next to nothing on one part of the band with a variable VFO over a few Khz. With something that size it would be good for backpackers and SOTA.
I think I've seen a few ssb projects out there. It's a bit more complicated, you'll need a balanced modulator, mic amp, audio section..
It might be a good idea to do something like this. A how to build a SSB transceiver. Even if it is QRP/p at 1W or less it could be something to give new radio users a look into theory and construction. But leave out technical so they have to go and ask other Elders where they are going with it so they can learn not only from you but also their club collective mind. Instead of cheap radios for VHF they learn how to build, solder and ask for advice. Different modules on different parts, connect together and see if it all works.
SOTA people would like to say on HF activation that they are running QRP/p and see how far they go. Could be something in the modular way to set up, TX and take down. Maybe a bare bones Yaesu 817. 1 band TX things like that. Kanga products were thinking of it some years ago but never got round to self build SSB phone QRP/p radios. So it is a niche build for phone especially one to make it work and use without it being a receiver.
William, you might consider a DSB transceiver like this one for your first try. home.alphalink.com.au/~parkerp/projects/projmicro40.htm
The first one of these I built, I made contact with the Qween Mary in LA harbor from S. Oregon with only 300mw. Since then I have built many variations with great results. Joel N6ALT
Tapped vaps, volpits. Tspped coil, Hartlry. Nice vid. 73 WA2KBX
Ooops! WA2KBZ
Can you build a tiny receiver to go with it? I know small ham receivers are a little bit fiddley but could you do it?
Sure. RX is a bit more complex though.
Do you have a video where you show how to make the frequency adjustable?
You can put a small trimmer cap in line with the crystal. It should give you a little adjustment.
Hello Kevin, What is actually generating the TONE? Is the tone being generated from the circuit? Is that what the first 2n2222a doing then generating it to RF on FEQuency via the second 2n2222a and crystal? Thanks a bunch in advance. I know Kevin has a lot of videos so if anyone else can answer this for me that would be GREAT!
I believe carrier wave transmission is just an on/off modulation, and the tone is generated by the receiver just as an indicator?
That was cool
Hi Kevin, I understand how the circuit functions as a transmitter, but the one thing i dont get is how you hooked it up for recieving. From what i can tell, the switch just swaps the antenna between the transmitter being on it and the reciever hooked to the rca jack?
Yes, and it also grounds the receiver jack when you switch to transmit to protect your receiver from excessive RF.
Dug through your channel but couldn't find any videos on building a similar QRP CW receiver. Any tips or resources you can direct me to for that? What kind of antenna are you using. New to this but very interested in low power CW communication on simple homebrew equipment. This is a great transmitter though; exactly what I'm looking for!
There are a lot of simple receiver designs out there. They tend to be more complex than a transmitter, and a little bit more involved to build. Direct conversion and regen receivers perform fairly well but tend to be quite wide and harder to use for CW, but doable. Superheterodyne receivers will have much better selectivity but are far more complex to build. Do a search on simple receiver and you should find plenty of projects to look at.
Tnx best 73s to u
Please do more videos best regards
thank you
I need circuit diagram for transmitter video signal for 1 KM .
BEST REGARDS
Would it work for CB if i changed the crystal and the low pass filter? (ofcourse with modulation)
That would be a different transmitter all together.
Awesome
Excellent job Kevin. I have a question or two. How did you insulate the underside of the circuit board from the Altoids tin? Also, it looks like the filter inductor was a T-50-3 type of toroid. What type of toroid was used for the RF choke L-1?I love making small circuits and stuffing them in Altoid tins. Thank you for making this very interesting video.73 de K7RMJ Frank
I used the same cores for both the choke and the bandpass. Under the PCB is some velcro tape which is both insulating from the bottom of the tin and keeping it from moving around.
I borrowed the low pass filter from this project.
www.delboyonline.co.uk/m0dad/construcion/tobacco_tin_transmitter.htm
L2 looks red to me, making it T 50 2. 14 turns will give 1uH, about right for 7MHz. Try stretching or compressing the turns, it may make for a better match into 50 Ohms. L1 is not critical being a choke, but should be well above a resonant value. >22uH will do, so ideally on an FT50 or similar core. For these sort of power values, a cheap axial choke is perfect. : ) 10 turns on a T 50 2 would only give 0.5uH, virtually a short circuit at HF : (
If you need to ask such a stupid question don’t think you will be able to make a transmitter ! Stick to watching football etc
@@loughkb the URL is broken sir!
@@lennyh500 I agree with you sir using a pre-built inductor is far better than winding a toroid or linear coil.
Question/Challenge: Can You Combine All Of The Other Elements Of The Radio Setup Into The Altoids Tin? Not The Telegraph Key, But Everything Else. Bonus Points If You Can Make It Portable!
Look up the Mighty Mite. It would easily fit in the tin.
Would it be possible to use multiple crystals attached to a multi position switch to achieve multiple channels.
Yes. You could also put a small variable cap in series with the crystal to get a very small tuning range.
you must know / tell which toroid you used!
otherwise it is no use, we can't do anything with it.
Was it not a T50-2?
friendly greetings from The Netherlands!
Rob.
Sorry, yes, it is a T50-2.
Great video. I need to find a kit or parts and built my first tranceiver.
What model scope are you using in the video? Russ - AD0QH.
It's just a cheap Hantek 5072p.
Russ, a good starter would be qrp-arci dot org/links stroke qrp dash kits dash bits dash and dash supplies. Many links for kits and parts. Terry - KB8AMZ
@@MoTown44240 //// qrp-arci dot org/links stroke qrp dash kits dash bits dash and dash supplies. //// Huh ???
@@SkyWire88 The URL has changed 2 years ago, just after posting. You could have Googled "qrp arci links" and found this. Easier to question though I guess. Try this new URL, "www.qrparci.org/links/qrp-kits-bits-and-supplies" without the quotes..