Scratch-built 40m 5W CW pocket transceiver

A homebrew 40m CW transceiver, built as tightly as I could manage with my current bespoke construction techniques. Does 100mW or 5W, inbuilt keyer, tunes 7010 to 7070kHz. Just the thing to have in your pocket for SOTA or a Park.

[@JT-py9lv]

You need to get a small business going and have DIY kits made up to sell. That is a gem !

[@Paul_VK3HN]

Thanks! Nice of you to say so. Kitting is a different game, it's a small business, and that takes considerable time and effort. There are many excellent QRP CW kits, the QRPLabs QCX is a much better receiver that this one, I recommend it!

[@byAlmad]

FANTASTIC !!! SMALL AND BETTER THAN A COMMERCIAL ONES !!! LOVED IT !!

[@Paul_VK3HN]

Thanks! Better than commercial ones, not so sure abiut that but good of you to say so!

[@peterarmitage5357]

Once again the project is fantastic, more pleasure building them and operating them, pocket sized very good.

[@Paul_VK3HN]

Thanks for commenting Peter!

[@andrewd4890]

Love it. Nice build. And some unique sound about the keying is not bad. Thanks for posting this, Paul.

[@Paul_VK3HN]

Thanks Andrew, the transmitted CW keying isn't perfect, some chirp in the higher power (5w) setting, but not too bad. Being an analogue VFO it drifts too! But all good fun. 73 Paul VK3HN

[@mohammadm5011]

Very good. Great activity, great, great

[@Paul_VK3HN]

Thank you 🤗

[@scottfoster5507]

Dude that is so awesome wish I was smart enough to make one .I keep watching and trying to learn I'm 49 so I still got plenty of time lol

[@Paul_VK3HN]

Plenty of time Scott.

[@frankartieta4887]

Exceptional 40 meter XCVR with a great filter All the bells and whistles A great enclosure And pocket size too I am quite jealous Best tu U

[@Paul_VK3HN]

Thanks for the nice comments Frank. It's a cute little analog rig and fun to use. All the best to you.

[@scottfoster5507]

I know very little bit I keep learning from channels like yours.thank you for your time and god bless brother

[@Paul_VK3HN]

I appreciate that! I hope you keep watching.

[@radioastronomy2001]

Very good video and fantastic design. I like the fact that you used MC3362 instead of transistors. Very elegant.

[@Paul_VK3HN]

Thanks Tom, it's a useful receiver on a chip, it is as good as any of the sa612 receivers.

[@nicktsakonas]

very nice! interesting idea for the enclosure! really small! well done!

[@Paul_VK3HN]

Tnx Nick, the offcuts corner at my local aluminum supplier has yielded a few odds and ends like this.

[@StephenCooteNZ]

A lovely bit of work and some nice morse. Thanks for sharing. Best wishes from Nelson in ZL.

[@Paul_VK3HN]

Thanks Stephen, hearing the contest DX CW stations was not planned that day, but the quiet location made them sound good in a simple receiver.

[@willian.direction6740]

Thanks Paul great radio well done. Wayne VK3WAM and I went to that restaurant for coffee after an activation on VHF. That was May 2012 when we did a mapping weekend for VK5 SOTA at his QTH. The sound of the RX and birds in the back ground is great we're pretty lucky hey. vk5cz..

[@Paul_VK3HN]

Hi Ian, you and Wayne are SOTA pioneers, thanks for your work in the early days. And congrats on MG in a region of Australia that doesn't give you a lot of help! Yes I love the birdsong in the background, we have an amazing outdoor environment here.

[@acestudioscouk-Ace-G0ACE]

Really well put together unit and nicely explained. Thanks.

[@Paul_VK3HN]

Thanks for watching and commenting.

[@nickwood4367]

Nice work. Well done!

[@Paul_VK3HN]

Thanks Nick.

[@ivanburyy6622]

Good idea, small radio with low noice. Hope, three crystal filter is enough to use /p. Nice video.

[@Paul_VK3HN]

It is just enough, you can hear the opposite sideband on a strong signal but only weakly. It's a pocket rig, a few compromises are necessary in the performance/size tradeoff.

[@CharlieMorrisZL2CTM]

Very nice Paul. I will have to try out that radio on a chip. A great way to make a nice small radio with discrete components. Charlie ZL2CTM

[@Paul_VK3HN]

Hi Charlie, yes the MM3362 is a bit hard to find but it is a superhet on a chip. You could add an IF gain stage if you liked, and an external digital VFO easily. 73 Paul VK3HN.

[@TheRubbersoul1991]

A beautiful little transceiver! Thanks Paul! 73, Phil VK8MC.

[@Paul_VK3HN]

Many thanks Phil!

[@MegaCadr]

Nice project!

[@Paul_VK3HN]

Tnx fer watching!

[@mladencukon9a3xz79]

Very nice Paul.

[@Paul_VK3HN]

Thankyou indeed, a comment from a dedicated radio constructor like you is appreciated!

[@rfdave3980]

HI Paul Very nice, I love it. KISS (Keep It Super Simple). Big fan of Charlie (ZL2CTM) and Now you. Excellent work.

[@Paul_VK3HN]

Many thanks Dave! Our channels are a bit different but we compliment each other in a way!

[@rfdave3980]

Hi Paul. On your blog you described the operation of the TDA7052 not able to connect a speaker because it a balanced output (BTL). You can connect a 3.5mm jack and have it connected to ground. All you need to do is put a electrolytic capacitor in series coming out of pin 5 and another coming off of pin 8. about 470uF should work positive connecting towards the output IC., then wire it to the stereo Jack then on to the internal speaker. If you want just a mono then only one Cap will do. This will take the DC component off the Headphones. Dave 73 VE3DFN

[@Paul_VK3HN]

OK I didn't know that Dave, I will try it, it would alleviate my main issue with the TDA7052.

[@genuine930]

So great! I want this one.

[@Paul_VK3HN]

Thanks, you should build your own version, even if it is simple to begin with, it's a heap of fun.

[@G4KDXlive]

A nice little rig. Congrats OM.

[@Paul_VK3HN]

Thanks 👍

[@JxH]

As a guess, I'd say that about 95% of the parks in North America would allow one to simply drive up to the appropriate spot, park up, set-up either at a picnic table or on your own fold-up furniture, all within a few meters from the vehicle. Extreme case: get out your 600-lb generator and 55-lb ICOM IC-7851, set-up the crank-up tower and antennas, fire up the BBQ, etc. "I'm at POTA K-1234, running a kilowatt and a 7-element beam at 50-feet." More seriously, I'd go HF portable with an FT-991A and a large 30A-hr LiFePO4 battery; it'll be within a few steps of my car. In the USA, same thing for many mountains (SOTA). Once upon a time at Lake Placid NY, my cousin told us that they'd climbed Whiteface mountain. We advised them that we'd also reached the top. "You climbed the mountain too?" No, we drove up, parked, and achieved the summit after a strenuous elevator ride to the top. There are a good selection of USA summits that have restaurants or doughnut shops at the top. Edit to add: Ah, so does yours. Cheers.

[@Paul_VK3HN]

Thanks for explaining that. In Australia drive-up SOTA summits are common enough but I haven't heard of a lot of operators setting up base stations. The extra effort and time doesn't make sense to me. As for restaurants on SOTA summits, they are rare down here.

[@user-uv4xe3cq2y]

Great job! Thanks for sharing.

[@Paul_VK3HN]

Thanks Ted. There's some fun to be had with a simple compact CW rig!

[@aurtisanminer2827]

It kind of resembles a yaesu 857 with that big knob. Lol. Pretty sweet unit!

[@Paul_VK3HN]

Yes an 857 in miniature. The knob is over-sized for the case but practical on a 50kHz VFO.

[@aurtisanminer2827]

Paul R. Taylor yea, I like the big VFO knobs.

[@bill-2018]

I'm impressed! That's very nice. The U channel is a good idea too. A great size if you only have a motorbike like myself and limited to what you can carry. I'll have to look up that MC3362. G4GHB.

[@Paul_VK3HN]

Thanks Bill, yes these compact rigs are perfect for bike, motorcycle, backpack. I have a more recent project, this one is 40 30 20 and 17m CW, 5W, using the same transmitter as in the QCX or the MTR rigs, but for,a twist, it is channelised. vk3hn.wordpress.com/2021/03/05/sp-x-a-pocket-rig-for-the-cw-activator-in-a-hurry/ 73 Bill.

[@user-ss6zt2mo1l]

Awesome little radio KB2QQM

[@Paul_VK3HN]

Thanks! It's not bad for such a simple design.

[@andrem.7042]

What a lovely rig and waht a brillant receiving quality! Very great! Do you have a List of the components and a building plan?

[@Paul_VK3HN]

Thanks! Details including the schematic here ...vk3hn.wordpress.com/2020/03/29/pocket-sized-homebrew-40m-cw-qrpp-qrp-transceiver/

[@kj-cn1dh]

Great design. There is a similar use of an FM chip by JF1RNR, one example is called the ZERO 6, a 6m CW rig that uses a TA7368 receiver on a chip.I would post a link to the block diagram / schematic but it was on a yahoo japan and no longer seems to be there and I couldn't find on wayback machine. I've got screenshots though so will see if I can find a way to upload them somewhere. There is a youtube video of the Zero 6. I presume because the MC3362 chip is designed for the FM broadcast band that it too could be used at 6m and maybe up to 2m.

[@Paul_VK3HN]

Hi and thanks for your considered comments. I did look around for other 'receivers on a chip' and there were one or two, but using unobtanium ICs. I grabbed a few MC3362s when they came up at a local disposals outlet. having a few meant the project could proceed. The Rx board was really an experiment. Altho it is not a great 40m receiver, it worked well enough to package it up into a little CW monobander. The full project writeup is here: vk3hn.wordpress.com/2020/03/29/pocket-sized-homebrew-40m-cw-qrpp-qrp-transceiver/ The data sheet shows up to 200MHz RF input so it would definitely work as an FM rx at 6 and 2m, probably quite well. For 6 or 2m SSB, maybe. It's a really neat IC, from 1996, aimed at the cordless fone, walkie talkie and small FM receiver applications. I note it refers you to a more recent replacement the MC13135, also from 1996, its datasheet shows 144 and 50MHz NBFM receivers with a stupidly low parts count! Those were the days.

[@vreism]

Good project.Maybe u put the cables front Side to back side it will ve nice

[@Paul_VK3HN]

Good point. It's a squash in that case! It's all a trade off. It makes you realise that designing a really good transceiver product is not that easy !

[@dxexplorer]

I've never built a proper transceiver so far... besides the Pixie, or the 49'er... or the Pititico. But they count more as "toys" )). I had a thing for this one that you built that I really like and I think I will make it my project to finish for summer. I really like the way you made it.. so small and compact. I really must build it as well )). Thank you again for the inspiration. Maybe by the time I finish it.. I may also know the code as well haha. 73 Paul.

[@Paul_VK3HN]

Hello Ciprian, thanks for your nice comments. We do share a love of small, compact and simple QRP rigs. This video gets a lot of views compared with my other construction videos, so I think most hams also like unique QRP projects, which is interesting in this era of high end SDRs. Your radios are very well built and you have a photographer 's eye, your videos and thumb nails have a professional look. I see you have been living on your yacht, that's amazing! Do you operate your QRP radios Maritime Mobile? I'd like to see some videos on your boat operating. 73 and keep making your fine QRP videos. Paul VK3HN.

[@dxexplorer]

@@Paul_VK3HN thank you for making the videos so I can watch them hehe. I don't know why it has more views... I watched them all. This one was good inspiration... and the other one about designing the layout and the PCB boards. About the yacht... I used to... for four years. Sadly I had to leave and come back home in Romania to help the family a little. I will go back in an year or two. Last time I had no equipment aboard besides a Baofeng programed on the marine VHF frequencies as the antenna to the one aboard was broken... so the Baofeng was my only radio )). I did not had a license back then so all I did was to listen to repeaters when I was in Miami. But when I will go back.. I plan on staying away from "modern technology" and use the radios as my only communication device aboard )). I can't wait for that as it will be interesting. Until then... I learn and enjoy the hobby on land like everyone else haha. The good part is that I have two years to learn and build as much as I can. I will send you an email a little later both about the hobby and the yacht life. I am just re-posting the videos I used to have about that on KZbin. I'm at the point when things got interesting so the new episodes will be fun )). We talk soon... 73 DE YO6DXE... greetings from Transylvania.

[@Paul_VK3HN]

@@dxexplorer Thanks for your comments. Homebrew QRP radio, and also QRP portable operating, including Parks and SOTA, are popular on KZbin. Building QRP radios is popular content as I mentioned, perhaps because the radios are simple and understandable. People like seeing hand made work, if they can see how it was made, and see the results. Your boating life sounds exciting and something that makes this period of your life special. We are not always free to pursue our dreams, no matter how challenging. Keep building and sharing your fine hand made radio projects, it is an honest and fulfilling pastime. 73 again, Paul VK3HN.

[@dxexplorer]

@@Paul_VK3HN Thank you so much Paul. For everything.. and indeed it seem that people like this. And I'm happy. Maybe this way we will have more getting into the hobby. Or who know ? Those that were not much into going up a mountain will start doing that )). Is good for health at the end... and you get nice views and adventures on radio waves as a bonus )). 73 Paul. I sent you an email as well. Have an amazing rest of the week. Today I rewatched some of your older videos from when I first discovered your channel. Always fun to watch and learn.

[@Paul_VK3HN]

@@dxexplorer Will continue discussion in email. Tnx es 73.

[@MirlitronOne]

Nice design, build and accompanying video! Kudos. M1GWZ

[@Paul_VK3HN]

Thank you very much!

[@Mynameistux]

I'm impressed VK5FAAD

[@Paul_VK3HN]

Thanks Harry.

[@vk2ihl]

Work of art, Paul! Have you tried hot air on suspected components to identify culpability for VFO drifting? If VFO coil, then get Murata N750 trim pot from Jaycar, RV 5720 and epoxied coil turns to core. DE VK2IHL 73

[@Paul_VK3HN]

Hi, no I haven't experimented with passive L or C options for VFOs. I just tried regular ceramic 1205 caps and a toroid. Much work could be done. I'd rather just redesign it around a compact si5351 and Nano or Pro Mini. I'll do that next time. Using an analogue VFO is fun, for a change, for novelty, but I wouldn't want to do it permanently!

[@davidepiombo5867]

Very good work, very nice! Congratulations!! 73 de IK1ZUV

[@Paul_VK3HN]

Thanks Davide. It was a fun little rig project and not too complex. .

[@pinvvv2398]

Great!

[@Paul_VK3HN]

Tnx!

[@grantmcduling9760]

I am impressed Paul. Well done. Grant VK4JAZ

[@Paul_VK3HN]

Thanks Grant, appreciate that coming from you 😉

[@darckan86]

WOW!

[@Paul_VK3HN]

Yeah!

[@va3ngc]

Lovely little rig. Do you have the schematics and build info posted on a website somewhere? Never heard of the Commonwealth contest before, and I live in Canada. I like the idea of having something for us Commonwealth countries.

[@Paul_VK3HN]

Yes, I'd not heard,about it either. I'm not a contester so I don't know how popular it is here. See wp.me/p628gp-29H for the blog post with schematic. Lots of other QRP and homebrew content on the blog. 73!

[@TheArtofEngineering]

Dear Paul….. The cobbling together of Frankenstein rigs is a learning experience! I am building the Alva (Swedish Pixie)…. With a VXO using Ceramic resonator C/O Alan Yates. Heard a VK3 CW (I’m VK2 land) but volume is VERY low. With the VXO disconnected the audio “hiss” is ok and LM386 sounds clean but when the VXO is coupled signals are their but rig is VERY low on audio (almost subliminal). … any thoughts?? Ps thanks 🙏 for these vids!

[@homebrewguykc1atw268]

Great video, I love QRP, and have several MC3362. Will make this. Thanks for sharing circuit. Subscribed

[@Paul_VK3HN]

Thanks for the sub! The 3362 receiver was a success. It had enough gain. This rig worked well, particularly the transmitter. However if I made one again, I would do the physical design around the free-running VFO. This should be in a fully enclosed compartment. The varactor tuning outside, of course. The rest of the stages can be laid out how you like. BTW the receiver design I used was copied from an 80m VK3 Fox Hunting Receiver, a standard monoband superhet with attention paid to RF and IF attenuation. 73 Paul VK3HN.

[@homebrewguykc1atw268]

@@Paul_VK3HN 3362 gives me a nostalgia, I will try with it, Thanks for your info

[@Paul_VK3HN]

@@homebrewguykc1atw268 Good luck.

[@Lanco.valdivia]

Good 👍👍👍

[@Paul_VK3HN]

Thanks!

[@scharkalvin]

Until now I'd not heard of the MC3362. Too bad the part is mostly only available today from dealers in China. Many of them are infamous for selling counterfeit or rebranded parts. You did a fine job in shoehorning that rig into such a small box. Good work on the circuit boards, I assume you designed them with Kicad. DId you have them made up or did you etch them yourself? I'm working on a design for a small QRP transceiver (actually two of them). The smaller one will be in a 6"x6"x2.5" box (surplus chassis from a former employer). I'm using an Si5351 as the VFO/BFO since I doubt I could make a more stable vfo. Controller will be an atmega328 (I have a ton of them).

[@Paul_VK3HN]

Hi @scharkalvin Thanks for the comments. The PCBs are hand drawn with a fine pen and etched in FeCl3. I got my MC3362 from a surplus source, so this is not really a reproducible design. This was the first analog VFO I've attempted in a while and it drifts, just barely acceptable. A better enclosure would help but in a serious CW rig I would choose a si5351 for sure. Good luck with your project!

[@johndeluca230]

Nice rig and great video, Paul. Congratulations! I have always had a question... when operating without frequency display, how do you know what frequency you are on for log information? Always wondered that, and perhaps you can Elmer me for a moment. 73 de John N1DEL

[@Paul_VK3HN]

Hi John, in this VFO controlled rig I included a crystal oscillator as a spot marker. The spot marker is powered momentarily on by pressing a small pushbutton. I then tune across and zser beat to the marker. You can hear me doing this in the video just before I call CQ. I'm netting my VFO to the known crystal oscillator which from memory is 7030. Apart from that I have no idea where I am on the band. The joys of simple homebrew! 72 de VK3HN K.

[@johndeluca230]

@@Paul_VK3HN Thank you so much for your kind reply!

[@trig6712]

WOW Excellent 73 GM4NNC

[@Paul_VK3HN]

Thanks!

[@Zeus-ub2zp]

Please Mr Paul, someday can you show us how you make the chassis with the holes (what equipments). Also, please what books do you recommend/have. Thank you. 73

[@Paul_VK3HN]

All my metalwork is done by hand, with hack saw, drill and files. To cut a round hole I drill adjacent holes around the inside diameter, push out the resulting internal piece then file till the edge is smooth. The best book to really understand radios like this is Experimental Methods in RF Design.

[@Zeus-ub2zp]

Paul R. Taylor Thanks :)

[@donalfinn4205]

Very well done?👍☘️

[@Paul_VK3HN]

Thank you! Cheers!

[@RadioMalopolska]

Look at Polish project "Kacper 2" QRP TRX we have 2 band and 3 band version .. Homebrew TRX .. Handmade better than FT 817 ... 1A 12v ... 10W QRP .. SSB . Cheap and very usefull in mountain expedition. 73 !!

[@Paul_VK3HN]

Hi and thanks for the tip to check oit Kacper 2, it appears to also use,MC3362 but it dies two bands, and SSB I think. Very interesting. I could not find a schematic, could you post a link?

[@RadioMalopolska]

@@Paul_VK3HN Kacper2 trx qrp its youngest brother od" Bartek TRX" from 80's homebrew sp5aht costruction A.J. from Poland

[@RadioMalopolska]

@@Paul_VK3HN here is link to my friend Mateusz SQ9PXB he conctructed a DDS with scanning .. some people have miniversion of Kacper .. Kacper mini . My version have 20sexond beacon to cq cq call ... with voice memory .You must find about MCxxxx ic ...73 ! kzbin.info/www/bejne/mn6TqGyBiLZneNU synteza is dds word in polish Good luck !!

[@RadioMalopolska]

@@Paul_VK3HN you must search word schemat trx Kacper in image web browser. Link is blocked in y..t..

[@RadioMalopolska]

@@Paul_VK3HN main ic is TBA120S . And DDS ... synteza .. must search.

[@user-ss6zt2mo1l]

When can I make one 😊

[@Paul_VK3HN]

Have you started yet ? 8^)

[@user-ss6zt2mo1l]

@@Paul_VK3HN not yet but im building the QRP Labs Mini kit for 40. It’s been a while since I built my NorCal Sierra back in 1995 😉.

[@edbeckerich3737]

Wow, I learned to hate IRF510s, Im going to have to try again. I could only get 30% efficiency, 1.2A on transmit. Horrible.

[@Paul_VK3HN]

They should do a lot better than that. Performance depends on the bias and supply voltage. If you can run them up to 18 to 24v they fly!

[@josephhager1933]

Make me one

[@Paul_VK3HN]

No, you have to make it yourself! Good luck, 73, Paul VK3HN.

[@michelemazzilli8260]

E possibile lo schema completo grazie complimenti 73de I0WV

[@Paul_VK3HN]

vk3hn.wordpress.com/2020/03/29/pocket-sized-homebrew-40m-cw-qrpp-qrp-transceiver/

[@michelemazzilli8260]

@@Paul_VK3HN grazie tante Taylor 73 88 from Mike ti Roma Italy

[@michelemazzilli8260]

Grazie Taylor per lo schema. Es ok molto facile 73 88 Mike Roma Italy

[@jamilsouzagodoisouzagodoy1099]

Porque não traduzem essa merda??!😒😒😒😒😒🇧🇷

[@Paul_VK3HN]

It's not merda