20m Band / 100mW QRPp CW Transmitter With One Tranzistor

[@multilecful]

Top tip from an old pro. Use a pcb mounted fuse holder soldered to a copper pcb scrap for clipping onto a TO92 metal transistor.

[@dxexplorer]

Ohhhhh I must put one more beer for you on the list 😁. That is a great idea indeed... and I have lots of those recovered from old boards. Thanks Nigel 😁. Bed time here... I am dead tired. 73

[@bill-2018]

@@dxexplorer I bent a small piece of aluminium with an extension piece and heat sink compound to fit round the P.A. transistors in my Pye Bantam. G4GHB.

[@i24714s]

In order to reduce the current through the quartz, I put a 5 kOhm resistor in series. It works great at 27 MHz. The generator works with a working quartz, but if there are problems with the quartz, the generator does not start. The Kolpits circuit is unstable, I used a quartz multivibrator, this is the best option, it works up to 100 MHz. The output signal is very similar to a sine wave, but the shape of the signal depends on the choke, optimally 75 μH.

[@dxexplorer]

Thanks so much. This I never tried. Time for some more experiments I guess 😅😅. 73, YO6DXE

[@olivierconet7995]

Very clever way of testing. It's tempting to add a second transistor as power stage, to let the Xtal oscillator at a quiet stable level 😁 (I know, this won't be a 1 transistor TX anymore) 73 de F1SOC

[@dxexplorer]

Hehe... yes you are right. I want to build one with two transistors as you described, or more as there is no limitations... but also making it with a VXO instead of a fixed frequency. I will try to cover the entire CW portion of the band 😁. Christmas time plans 😅. 73, YO6DXE

[@bill-2018]

Very good, I like simple stuff. I did something like this last month for the G QRP Club 50th Anniversary. It might appear in SPRAT. They wanted some project with 50 in it so I used a single BFY50 transistor. It's chirpy on 28.060 MHz and 24.906 MHz but calms down on 18.086 MHz and 14.060 MHz. It pulls the frequency off at 10.116. It doesn't work below that. A different r.f. choke needed. I built one many years ago for 1.910 MHz. Got 26 miles on it. G4GHB.

[@dxexplorer]

I also like these simple projects. I think this is why I always loved and always will love CW... because of the simplicity of the equipment needed. A handful of parts and you are on air in no time. And with the right conditions even with low power you can reach really far... even with no giant Yagi antenna 😁. I know in 160m, 80m, 40m and now 20m it will work fine with little adjustments needed for each particular band... but if I get crystals for the 10m band, I would love to test one of those versions as well. 73, YO6DXE

[@bill-2018]

@@dxexplorer As you say a handful of parts and you have a tx. I have a 61BT valve out of a non-working oscilloscope I was given and put it on 5.262 MHz, about 2 Watts. I like 60m and put a Pixie on 5.262 MHz as well, furthest QSO at 180 miles with a SWL report for that QSO from Utrecht at 220 miles. 350 mW out into a low inverted vee. 73, G4GHB

[@dxexplorer]

@bill-2018 I was just talking yesterday with one of my mates about building a tube transmitter. He sent me a schematic with a penthode that I should try as a first. I need to get my hands on some transformer first. I love tubes, but I never built anything with them. Pixies are fun too. Sadly here in Romania we can't use the 60m band 😔. 73, YO6DXE

[@graemezimmer604]

Another trick with dual crystals is that they will tune much further in frequency (via C2). You should also try a series LC network (instead of C2), you'll find that will also tune much further.

[@dxexplorer]

Ohhh yes indeed... a VXO would not be bad at all. I didn't do that just because I wanted to stick as close as possible to the original schematic I found, but I am preparing something in that matter too ( maybe around Christmas ) 😁. 73, YO6DXE.

[@davidportch8837]

Thanks for another interesting video Ciprian. I was just wondering... Is there any reason (other than cost) for not just simply using two crystals in parallel to get the 700 milliwatts?

[@dxexplorer]

I made the board with the idea in mind that I will always use the bigger crystals since I know that the smaller ones have this issue. Is just that my buddy Vlad sent me the little ones to build some stuff for him... so I used what I had 😁.

[@ScratchyCode]

14:32 Schumacher 😂

[@dxexplorer]

😅😅😅😅😅

[@jasonmilldrum]

Nice experiments! In my experience, it's not worth it to push a single stage to do so much. Adding a second stage to the transmitter would only take a few more components, would be much more stable, and give you the chance to develop even more RF power than the original circuit.

[@dxexplorer]

I agree with you. Well... I like the sime design using just one tranzistor I won't lie. Is fun to play around with it and you have some satisfaction when doing a QSO. But when it comes to stability and performance... I think I will put this simle design on steroids... around Christmas time if I have the free time 😁. 73, YO6DXE

[@alanuk8677]

Nice little project! 73 M0KOE

[@dxexplorer]

Thanks so much. I really love this little TX. So simple and easy to build. And I learn a lot too on the way. 73, YO6DXE

[@alanuk8677]

@@dxexplorer Trying to order some PCB'S now. Thanks!

[@dxexplorer]

@alanuk8677 Always a pleasure. Glad I uploaded the corrected version last night before posting the video. The transistors had the pins the wrong way. Not sure who made the footprint but I know to double check now when importing something into the library 😁. 73, YO6DXE

[@alanuk8677]

@@dxexplorer ah right. PCBway says my order is under review so not sure what's going on there.

[@dxexplorer]

@alanuk8677 Is because I updated the file and they didn't had the time to check the GERBER yet. It should be fine by tomorrow.

[@jcbacol]

👍👍👍

[@dxexplorer]

🙏🙏🙏

[@LouiseBrooksBob]

Would it be possible to swap out components and make a 10 metre version? Or any HF band?

[@dxexplorer]

If it works on 40 and 20 I am sure it could work for other bands too yes. I will play with the 80m version these days, and I don't have a crystal for the 10m band but if I find one... I will make some tests and put all the info in the blog article. 73, YO6DXE

[@LouiseBrooksBob]

@dxexplorer thanks, I was thinking this kind of circuit seems perfect for a low cost beacon. I would like to make one for 10 metres.

[@dxexplorer]

@LouiseBrooksBob I think you can just recalculate the LPF for the 10m band, then replace the crystal and test it as it is... and eventually adjust the value of C3 if it doesn't oscillate. I will try to find a crystal for the 10m band as well, this way I can make lots of versions of it haha.

[@LouiseBrooksBob]

@@dxexplorer thanks! That's really helpful.

[@bill-2018]

I did one using a BFY50 but it's chirpy on 10m and 17m. Okay below those frequencies. G4GHB.

[@ABHIJITHMOHANAN1997]

❤❤

[@dxexplorer]

Thank you so much for watching. 73, YO6DXE.

[@ABHIJITHMOHANAN1997]

@dxexplorer you are welcome

[@eppe8755]

Can I convert this to 1Mhz?

[@dxexplorer]

I haven't tried that low yet, but I do want to try a 160m version ( 1.8MHz ) and if that works then I am sure 1MHz would work as well. I built a Pititico transceiver for 160m band and it worked so I don't see why this wouldn't work.

[@bill-2018]

Years ago I built one with one BFY50 with something like 30/40 turns on an Aladdin coil former with slug and maybe 30 SWG in the collector with 1,000 pF across it and a 1.910 MHz xtal and took the output off the collector. One 22 KΩ resistor to the base. Colpitts with 220 pF and 265 pF. Dead simple. G4GHB.

[@dxexplorer]

@bill-2018 That is homebrew style all the way. I keep having in mind to build one using really old recovered components ( that are still decent good ) and make some vintage style transmitter 100% homebrew. I don't know if its just me, but I have a diferent kind of satisfaction when using those.

[@bill-2018]

@@dxexplorer Good luck with your project. I love building stuff, h/b ssb/cw QRP tcvr, dipoles, inverted vee, 4 el collinear, digital freq. meter years ago from a kit, Wheatstone Bridge type SWR meter. Repairing cheap tatty gear, TW TopBander £5, five Pye Bantams £6, tatty Wireless 19 Set £105 but I wanted QRP and xtal on tx using the EF50 valve and new rx input circuit and h/b inverter inside. That needed a lot of work, re-winding two coils and other things. Racal RA17L needs attention. 73, G4GHB.

[@dxexplorer]

@bill-2018 I also love building stuff related to the radio hobby. I don't know why I am so attracted to this since I was a kid. But as they say... boys and their toys I guess 😁. Love every little bit of this. Good luck with your projects as well. I think this winter I will reserve time to make enclosures for all the finished ones and this way all the projects will be completed. Meanwhile I also have some antennas work to do as well. After I moved in this new location I simply "improvized" antennas really quick to do the job... but I need a better setup in this matter. 73, YO6DXE

[@F4LPM]

Amazing my friend. 73 F4LPM

[@dxexplorer]

Thank you hehe. I am building one for me as well now 😁. 73, YO6DXE and have a wonderful Sunday.

[@F4LPM]

@dxexplorer Nice!

[@The_electronics_nerd]

Hi dx explorer

[@dxexplorer]

Hi and I hope you had a great weekend. Almost over now 😁

[@victimovtalent6036]

0.0001kw transmitter

[@dxexplorer]

😅😅😅😅😅