Building The QRP Labs QCX Mini CW Morse Code Radio.

[@JosephAnthonyJosefius]

I ordered this kit today for 20 meters. I wish I had seen this before I chose it.

[@QuiltersHandyman]

Enjoy your videos Gil.....I put off building the first QCX I bought because of the toroid windings. Finally jumped in and found out they weren't as bad as I thought. I agree with you that the way the manual explains how to wind the toroids...well didn't work well for me either. I ordered some different colored wire and wound the smaller number of turns each in different color and, for me I could keep track of the number of windings much easer. I also agree that. Hans puts out not only a top grade product but also provides one of the best manuals I have ever used. I am an old man and started my hamradio career in the early 1960s. the days of tubes....or valves as they were called some parts of the world I have put together a number of Heathkit projects that were accompanied by step by step assembly instructions plus many many drawings. Hans certainly rivals them. Thanks again and keep up to great videos.

[@RadioPrepper]

Much welcome George :-)

[@Steve-GM0HUU]

Good review Gil, thanks. I built a QCX-mini for 17m a while back. Thought it was a fantastic kit and a brilliant development of the original QCX. The QCX-mini is easier to build than the QCX as more of the components are SMD and already installed. The assembly design of the PCBs and case is genius. As with the QCX, the features and performance for the cost is amazing. I quite often use mine in the shack as well as for QRP/P just because they are so nice to use. Just carefully follow the very concise manual. What I did was print the manual so that I could tick off each step. It is also useful to keep for reference as it also has all the operating instructions.

[@mikemiles3068]

I am thanking about getting this little rig just for my emergency bag but I will get the pre-built as my kit day have ling past. Good video Gel❗️

[@acestudioscouk-Ace-G0ACE]

It's good to see videos where it doesn't go right first time. It reminds us that things can go wrong and comforts us mere mortals who always mess it up! LOL Thanks for an honest video.

[@Rolfunther]

Love your videos, Gil. They are a great addition to the community.

[@RadioPrepper]

Thanks!

[@2EOGIY]

14:00bargraph and a digit. The number shows value and the bargraph fraction part of value i.e. 6 and two bars is lower than 7 and 1 bar

[@RadioPrepper]

Yep I know.. It only changed three bars on the same number.

[@jertres2887]

@@RadioPrepper Ok, only changing three bars on the same number is not right. the original batch had some bad op amps, that variety of op amp had all different manufacture dates stamped on them making me think the board house got a good deal on a bag of seconds that mostly worked ok but had several duds in the bag. My recollection is that it produced similar symptoms at least some of the time. I think Hans switched board houses and now he tests every board before he ships it. So if it’s from the first batch that could be the problem. Replacing the bad op amp fixed it but you had to diagnose which one was bad or replace all the op amps of that variety. Rarely you get a surface mount part where the solder joint is marginal and might fail. So it might have gotten through hans’ test, failed later and probably still looks ok. Not it might not look ok, so microscopic like inspection of all the op amp pins might produce a suspect. That would be a long shot but might be cured by reheating the joint if you could figure out where the problem is. If you ask on the list, someone who had this problem will probably remember the details and be able to help you, if that’s what is going on. The op amp variety in question is a low power consumption one with very good performance but that performance is really critical only in one location and the rest can be replaced with a cheaper variety with little change in overall performance. From around January of 2021: “I'm happy to say that my 20m QCX-mini now has a receiver with balanced/ quadrature I&Q! It turned out to be IC7 and once I managed to replace it all was well. FWIW it turned out all I needed to do really was use my finger to fault find. Holding a small metal probe to the inputs of each op amp in the audio chain in turn, working back from IC9, I soon found that I didn't hear any hum from the input to IC7B.”

[@RadioPrepper]

Thank you for your time. It is the latest batch though...

[@bitutube]

Gil - Thanks for this video. Well done. If you are not already familiar with a circuit board holder such as the Panavise, such a tool makes soldering these small boards and components much easier as you can use both hands while the board is held steady. I’m about to start building Hans’ new QMX this week. Jim - N7RCS

[@RadioPrepper]

Right! I've been wanting to get one of those.. No idea why I've delayed..

[@nathanw851]

I did the same with T1. Bought the 40m kit, attempted it twice, put the kit away for months, then dug it out and completed it last week for 20m, where there're less windings. I agree, the loops thing is confusing - I found doing each winding individually much easier. Overall, T1 was definitely the hardest part of the kit.

[@jertres2887]

Per Hans “One is 500-ohms (written "501" on the top of the component) and the other two are 50K (written "503")” And “If one or more of the trimmers is at the extreme end of its range then you can appear to get no minimums... If you want to reset the trimmer to the middle again: keep turning the screw clockwise and clockwise and clockwise, and listen carefully, you'll hear a very faint "click" once per revolution, when it is hitting the end. You can then turn it back 12 turns anti-clockwise and know you're in the middle. If you do this with all three pots, you'll know you are in good shape with all trimmers in the middle, and can try again. “ fwiw es good luck!

[@RadioPrepper]

Ok thanks. My hearing isn't that great anymore I fear..

[@ianwraith3251]

I was daft enough to buy one of the first batch of these which arrived last January. All went well until the calibration stage where the results just didn't make sense. Using an oscilloscope I determined that one of the pre-soldered on op-amp ICs was faulty which annoyed me. I suppose I could have tried de-soldering then replacing the op-amp but by this point I had enough of this kit so sold it to another amateur for spares. He later reported back to me that 3 of the op-amps were actually faulty ! Looking on Twitter at the time it seemed that quite a few of the first batch suffered from this problem and for later batches QRP Labs started testing the part built boards before sending them out to customers but that wasn't much help to me.

[@RadioPrepper]

Wow, good lesson about early adoption here..

[@HALEdigitalARTS]

I got the 40m, but I'm a wuss, I had it assembled. They were able to get well over 5w. I'm looking forward to testing it out soon.

[@passattdise]

You can adjust the frequency it transmits on by the adjustment of the IC chip ratio to the actual crystal frequency your crystal produces.... it's a mathematical equation adjustment. Keep in mind the crystal oscillation rate varies with the temperature of the crystal inside the kit. Read the instructions for how to do it.

[@MrScotchpie]

Hoping you are keeping well. Now its Spring better weather is just around the corner. Take care.

[@RadioPrepper]

All right thanks, I will be reposting soon :-)

[@PreparednessVeteran]

An excellent little package. Good skills.

[@adzbasslines268]

I found Elecraft has the best explained instruction manuals that I have ever read! 4SQRP kit manuals are also just as excellent!

[@RadioPrepper]

Also yes! I built two K1s and one K2 :-)

[@qrplife]

I was happy to pay Hans & Co. 50 bucks to build and align it for me :)

[@cwguy8960]

Gil, did you ever get your QCX Mini aligned properly? I have built 4 of these successfully, and the alignment all went by the book - you should see definite nulls as you adjust the sideband suppression. Also, for frequency, there is a way in the alignment menu to adjust the reference frequency and get that radio spot-on. As you noted, the build is not difficult, but one must be cautious and follow the detailed instructions for a successful built - the end result is well worth the attention to detail. It's a fantastic portable radio for SOTA - loaded with features, and very affordable for what you get. Looks like it's been a year since this video - I hope you got it working to your liking!

[@RadioPrepper]

Hi, my first two worked fine, I need to get back to it!

[@WilliamParmley]

Very helpful. I appreciate the discussion about why 40m is the optimal choice for you. I would tend go with 20m because of the size of the antenna, but 40m is probably the band most likely to be open somewhere 24 hours per day. I think you made a very good choice.

[@RadioPrepper]

Thanks. Portable, antenna size is usually not a problem..

[@4youian]

Another way of doing the IQ balance would be to set the potentiometers to a nominated resistance value before installing them so that at least they are already in the ballpark. :) 73, VK7IAN

[@carelmulder8035]

Just finished a 20m and 40m kit some days ago. I had to bend a metal lip of the display flat against the PCB because it was sitting against one of the blue potentiometers. So alignment of the two PCBs did not go well. That was the case with both kits. Also the nut + washer did not fit far enough on the BNC chassis part. The bayonet clamping of the cable part had too little space and did not fit on the chassis part. Mounted without the knurled ring. Both are great QRP rigs however. I'm very happy with it! Carel - PA0CMU

[@RadioPrepper]

Great. I did not have those problems but it was a tight fit..

[@fireflaze]

Did you do the calibration per the manual? That is where side band suppression is accomplished. Added: I see that you mention it. If you didn't iterate over all three blue potentiometers oh, probably at least three times or until no more changes then it may not be good enough yet.

[@RadioPrepper]

There is no stop on the pots, so hard to say..

[@jertres2887]

@Radio Prepper you have to go back and forth tweeking each one in turn going around again and again until you cannot get them all any better.

[@jertres2887]

@Radio Prepper if you get really lost, power down and use an ohmeter to set each pot at the middle of its range and start over. Also as you get near one end of the indicator, the range or scale for that indicator changes, up or down depending on which way you are heading, and this can confuse you if you are too focused on just the bars and don’t notice.

[@RadioPrepper]

Thanks guys, I will try again.

[@fireflaze]

@@RadioPrepper No physical stops, but those pots are approximatly 25 turns end to end. At the ends, in a quiet room, you can hear clicks as you turn. If I get confused as to where I am I just turn till I hear the clicks and then turn back 12 turns. That's close enough to the middle to start over.

[@kamilsp7]

Great kit to build. I have only one complain on my 30m version: I hear audio clicks when turning vfo dial. There are 2 clicks per each dial step. It's a little bit annoying when tuning across band.

[@RadioPrepper]

Weird. My 30m did not do that..

[@wino4340]

There's a KZbin video out there where the guy had the problem with audio clicks...he showed the fix for it, but I'm sorry I just can't remember the KZbinrs name/channel. But the fix is out there .

[@ralphwilmot6351]

Hi Gil. QRPLABS latest kit the QDX for Digital FT8 FT4 WSPR is a similar kit to the QCX which covers all of 20 30 40 80M which I have found to perform very well. My first QSO on FT8 was with a VE station on 2w. The receiver reception is as good as my IC3700. I have matched this with a Raspberry pi 4B 2Mb to make an almost portable setup. Especially ideal for WSPR use on my 80M EFHW aerial covering 20 40 80 matched for low power consumption without using my main rig. I do like your video content. Tnx 73 G4PEY

[@RadioPrepper]

I have a video on it ;-)

[@vincei4252]

Happy New Year! Hope all is well! I have one of these and looking forward to building it too!

[@RadioPrepper]

Happy New Year!

[@James-hb8qu]

"Brandon moment" LOL. That's worth a subscribe right there.

[@cliffbatson]

No. Keep politics out of the hobby, please.

[@qrptedmac]

I just received my 20 and 40m QCX mini’s. I did have to email Hans at qrp labs because I couldn’t get the bnc male connector on the coax to lock onto the bnc female connector. Hans suggested removing the washer under the nut on the transceiver and it then locked down.

[@RadioPrepper]

Interesting, I had no issue..

[@qrptedmac]

@@RadioPrepper Yes Hans said that was the first he had ever heard of that. I sent him a pic of my Kx2 with it connected to and the QCX with the connection halfway from lock. He suggested removing the washer from behind the nut. That did it but I couldn’t figure out why mine was a problem. And that’s on both the 20 and 40m transceivers.

[@fireflaze]

I see this with the more recent kits. The last four I've built I had to leave the lock washer out. I think the supplied nut is thicker. Don't know for sure because all my previous mini's are sold. Build/sell, repeat. :)

[@qrptedmac]

@@fireflaze Oh. Well good that makes me feel better. I thought it was the BNC connectors I was using. I kinda thought that it had to be either the nut or washer was thicker but Hans said that he hadn’t heard of any problems like that before. But you’re proof that something must have changed. Thanks for the info.

[@julianopificius6910]

@@fireflaze Hi Mike :-)

[@QRPCW]

Un juguete QRP 😍, maravilloso trabajo de montaje 👏🏻💪 73/72

[@quantumradio]

Good video Gil. I've been looking at the QCX mini transceiver; however, my first objective is to become proficient in CW at the 10 - 15 WPM range. I requested membership to the Long Island CW Club yesterday. Maybe in a few months I'll be looking at this kit. 73!

[@kn6eze]

If you don't have a CW rig already, I recommend getting a QCX, paddle, straight key, and a resonant antenna WHILE you're learning CW. Getting on the air is IMHO the best way to learn CW. Ten to fifteen WPM is a great goal, but you don't have to be at that proficiency level to get on the air. By getting on the air sooner, you'll benefit by: a) being able to decode real CW code which is sometimes far from the perfect code sent by training programs, b) learn how to operate your radio for when you are ready to get on the air, and c) begin making QSO's as soon as possible, d) using the decoder in the QCX in practice mode to help see if the code you're sending is legible. SKCC is a great "slow code" group to get started with, and three exchanges are very simple and forgiving. Anyways, good luck in your CW adventure!

[@RadioPrepper]

I would highly suggest not learning below 15wpm no matter how hard it is.

[@wino4340]

LICW great club.

[@quantumradio]

@@kn6eze Thank you for the tips. All make sense. I've done 2 CW QSOs so far in the spirit of learning by doing. 73!

[@quantumradio]

@@RadioPrepper OK. Thx for the advice.

[@fredjensen1683]

Great info....but Where do you get a power suppy or rechargable battery for this? Also what is the simplist antenna you can use for greatest distance?

[@RadioPrepper]

You can use three 18650 cells in serie. Use a half-wave end-fed antenna...

[@jesusreverte2971]

Great vid, Gil. This radio really encourages me to learn CW. I've never passed from 10-11 letters/signs. Best of luck fixing the band suppresion issue. Unfortunately I can't help on that. 73, EA3HVG PD: I have doubts on the band. You recommend the 40m, but I wonder, would't be interesting an upper band just for having shorten and more practical antennas? I wouldnt mind using warc bands. I think I'd never have enough level for contesting.

[@RadioPrepper]

Depends if you operate portable or not... In the field antenna length is no problem.. That said I am a big fan of 30m :-) Upper bands are not opened as often. 30m has no contests too :-)

[@eddy2561]

I wish Hans offered T1 prewound for a few extra bucks, Elecraft did so with their K2 kit which I built in 1999, although I did wind all toriods myself back then. Hams around the globe are aging and this was a difficult kit for me due to old eyesight and shaking hands....just my 2cents. I also found aligning of the sideband suppression pots to be non responsive. So, not my cup of tea I gave the QCX mini away Belle vidéo Gil 73/K6SDW

[@RadioPrepper]

It's really easy once you understand how the wires go..

[@julianopificius6910]

There are a few of us will build these kits for you for some nominal price - sometimes less that QRP-Labs' factory assemble adder. I do it for subscribers to the groups.io forum. It would be no trouble to do a partial build: wind, install and continuity-check the inductors, then send it back to the owner to complete the rest, if they so chose.

[@davidelley8979]

My old electronic teacher used to get so mad cutting components legs after soldering.

[@52Warlock]

Why? Did the teacher want you to precut the leads? Curious.. thanks.

[@kamilsp7]

@@52Warlock This is rather about putting tension into solder joints when you cut leads after soldering. There is theory that such stressed joints would be more prone for further degradation ie oxidation, cracks, etc. Heard this many times.

[@davidelley8979]

@@52Warlock yes precut the leads, as not to stress the solder which could lead to issues in the future...

[@davidelley8979]

@@kamilsp7 spot on that was what was drummed into us, especially with regards to mil spec applications.

[@RadioPrepper]

I never did that but I guess for some sensitive applications it makes sense.

[@ericmartin372]

Super video, j'ai aussi un qcx-mini, sur 20m. Tu as 2 modifs a faire, rajouter un fil pour la mesure de la tension (ta batterie est vide sur l'ecran). Et un condo aux bornes du jack 3.5 du speaker, pour eviter les retour hp dans l'ampli bf.

[@RadioPrepper]

Merci! Je voulais faire là mod du voltmètre mais n'était pas certain des contacts à souder. J'aimerais une photo du dessous du circuit imprimé avec la mod..

[@madcarew5168]

Did you fit the 25mhz txco frequency stabiliser? 73

[@RadioPrepper]

No.

[@jdotson41041]

Gil did you ever field test or make contacts with this radio?

[@RadioPrepper]

Not yes, I need to get back to it!

[@azertydu80g.r.p.s]

Col de Vence . Trés bon endroit pour faire du DX 👍👍

[@DAVIDGREGORYKERR]

Don't you think that other bands should be supported like 432Mhz or for that matter 1296 or 2304Mhz which just needs stripline inductors which makes for a much smaller board.

[@RadioPrepper]

I talked to Hans about that, as I'd love a 2m ssb radio. Apparently the matter isn't trivial and he doesn't have the time. Hopefully someone will make one...

[@wernermitterbauer428]

Hello Gil :) Could you do another video about your military radios? This is a very interesting topic

[@RadioPrepper]

You are not the only one asking, so yes!

[@wernermitterbauer428]

@@RadioPrepper Thank You Gil :)

[@Obeeewaan]

I am building the same kit on 20m and have similar difficulty with 3 pots .. I have a scope so my troubleshooting is bound to take longer.. while I re-learn how to use it.. hah..

[@RadioPrepper]

Keep me posted..

[@JustMe-dv5ix]

Hello Gil, this is Ken N7KO, It has been a while since you built this kit, but I have a question, Did you place a jumper from 12v to DVM in order to get Battery indicator to work? If so what did you have to do to get to that area to soldier in the jumper?

[@RadioPrepper]

Hi, I think I did, but honestly I don't remember..

[@JustMe-dv5ix]

@@RadioPrepper OK Gil TU and may God bless you.

[@JustMe-dv5ix]

@@RadioPrepper Hello Gil, it is me again Ken N7KO. Just to give you an update on my question about placing a jumper to activate battery level. I ended up just removing two screws on each end panel that holds the back, Then as you know the back lifts off. This will expose enough pcb to pashion a jumper and carefully placing it in the two holes 12v+ and DVM then solder in place, tight spot but worked. Here is a short video of working on the 40 meter QCX. When I removed the back I noticed the pcb board had a bow in it, and up on inspection I noticed the bolt holding the transistors down was to long, so I ended up removing four screws and removed the board then ground off about 3/32 of the bolt. The othe two radios were fine so all I had to do was to remove the back and solder in a jumper. kzbin.info/www/bejne/Z4LRg6d5jq5mjc0 Oh the 40 meter was assembled at the factory.

[@bob-N4REE]

Did you ever solve the extra sideband problem? BTW, I'm subscribing just to hear more from Brandon.

[@RadioPrepper]

I haven't gotten back to it yet, but I need to.. Suspicion is on T1..

[@rodneylamay5926]

hi gil love ur you tube channel .do you like the qcx mini over the sw3b cw tranceiver i can only perchase 1 .. thanks 73s . rod ki6pxv

[@RadioPrepper]

I have not tried the sw3b, but it does seem interesting with three bands.. There is also the uSDX..

[@passattdise]

"Maybe I had a Brandon moment"

[@RadioPrepper]

Oops, did I say that? Nah ;-)

[@nvrumi]

Made me laugh too...🤣

[@John_Smith__]

Yup, that also made me laugh a lot 😀

[@2j4ez]

shaving brush on top of your mic doesnt work you still have a beard. the screen looked like it was missing some segments or was was that the way it was positioned in the sun light?

[@RadioPrepper]

Probably the light..

[@billryland6199]

I built an original QCX for 40 meters. I have been waiting for the QSX to be available but Hans has abandoned the 90% of hams who want an SSB transceiver. He is putting his priorities and development time on multiple versions of the same rig instead of the QSX that can do everything. I bought a Yeasu FT-891 instead. It can do everything with more power.

[@RadioPrepper]

But more current.. I am waiting for the QSX too..