QCX in QRP Labs enclosure, by Greg W3NW
A lot of people have asked whether the QRP Labs enclosures can be used for the QCX. My answer has been, not easily - the problem is that the audio gain potentiometer in the QCX is slightly too large to fit in the available space to the left of the LCD module. Greg W2NW has shown how to resolve this problem, by using a smaller potentiometer. He also replaced the supplied rotary encoder with an optical rotary encoder type, which required no circuit or firmware modifications. I like the method of mounting the PCB in the top half of the enclosure, which keeps the LCD wires as short as possible. Greg writes:
"QRP Labs enclosure works very well for QCX even allowing enough space for an optic encoder.
PCB is mounted on the top shell of the enclosure.
Right and left internal PCB holding ridges on the bottom shell filed down slightly in the front to accommodate optic encoder and the volume pot as shown.
Mouser part numbers:
5K audio pot - 313-1200F-5K (supplied one is a bit big)
optic encoder - 62A01-01-050S
My QCX gives out 3 wts on 20 m, has great sensitivity, very low noise level and excellent unwanted side band suppression.
I changed audio filter for 480Hz as per directions on 4stateQRP web site with no issues."
QCX-40 by Ed WA4MZS
40m QCX enclosure by Ed WA4MZS
Ed says: "Wired the cabinet for either AC operation or for DC with an external battery, selectable by a switch on the rear panel."
Beautiful small QCX enclosure job by John PD7MAA
John fitted the QCX in this small aluminium extruded enclosure, with the help of some button and shaft extenders. See the full story on John's blog at http://pa-11019.blogspot.com.tr/2017/08/qrp-labs-qcx-5-watt-cw-trx-kit.html.
Interesting QCX enclosure by Nigel M0NDE
Nice compact enclosure by Vasil LZ1WF
Plastic enclosure, with 16V 2000mAh battery, and travel paddle.
Smart custom-made PCB enclosure by Ken WA4MNT
Ken provides detailed construction information in this document (CLICK).
FREE QCX case by Lou VK5EEE
"Finally hit on a FREE case that actually comes supplied with the QCX":
It has SEVERAL advantages:
- FREE (comes supplied with the kit)
- Can be easily painted, labelled
- Kept blank "as is" for spy radio set
- Can open lid for access to LCD
- Can cut display hole for LCD
- Can plug in external key if desired
- Can easily fit internal 9V PP3 battery
- Extremely light weight
- Fits into a large trouser or jacket pocket
- Otherwise can be concealed in underwear
- Easy to smuggle across borders
- Can be set up with probe as "test gear"
- Address can be removed for deniability
- Inside of lid can be used for "cheat sheet"
- No special tools required to "drill" holes
- Protects against flies, eyes, spies
- With umbrella protects against rain, snow
- With ear phones is completely incognito
- For traveling can be padded out with foam
- Perfect fit, no need to adjust dimensions
- Press lightly on lid to activate message 1
"I'm quite happy with it, and had been wondering about it for some time. Having now tried it, it is definitely a keeper. And all along we've been thinking the QCX comes without a case!"
QCX 30 in Hammond case by Robin HB9DEF
"I have recently completed my QCX for the 30m Band (Firmware: 1.00). I have mounted the PC board on a copper laminate board (see photo), which is placed inside a Hammond box. The LCD is mounted using plastic nuts and screws (M3) and rubber grommets as spacers. A discarded PC ribbon cable forms the connection to the LCD on the box side. The cable is routed underneath the copper board. All other connections to box sides are screened."
"The back of the Hammond box has on the LHS (as viewed in the photo) a DB9 PC male socket for the GPS antenna. I use a 5m DB9 shielded cable to a small plastic box housing the GPS board and antenna. Placing another DB9 socket on the GPS plastic box was a bit of a fiddle. Next to this socket is the power socket. On its right is a fuse holder. Then a stereo jack socket for the paddle key. This is followed by a binding post for earth connection. On the right is a BNC socket. The RX gain control is on the left of the front panel and the rotary encoder on the right of the LCD. The encoder is mounted on a piece of Vero board to hold the shielded cable end."
3-D printed QCX enclosure by David EA7HYD
"Box made with a small self-built 3D printer. I am very happy with my QCX kit. In the tests of the first day, transmitting with a yagui of 3 elements, OM gave me a distance of 7,500 km (4,350 miles) I did not believe it !! I worked with 13 volts, which gave me a power of 3.6 watts. I hope to get the same results in the field with a wire antenna (HI HI)."
3-D printed QCX enclosure by Dave G8XUL
"My QCX in 3D printed case. The objective was to case the QCX with all controls mounted on the board and without shaft extensions. The box has room for a LIPO battery and has a connector for my GPS."
The design files are available on thingiverse: https://www.thingiverse.com/thing:2661221
3-D printed G8XUL case by Colin N5GG
This is Colin's print of Dave G8XUL's case design (see above).
QCX-40 #943 in the 4 State QRP group's Little Blue Box, by Jim W0EB
"Well, this enclosure for your QCX is doable, but definitely not for the faint of heart or for someone without at least a drill press (I have a small milling machine, even better) and a decent set of drill bits and files. Extreme care must be taken in making sure everything fits without interference."
"I ran into several cases where I had to rethink my original plan and remove something until I had another plug in place (power jack vs one of the ribbon cables for the display). Close, but it worked. The one thing you will have to do is mount the supplied volume control somewhere other than the front panel. I happened to have a miniature 5K volume control WITH on/off switch and a matching knob to fit the 1/8" diameter shaft. The push button switches are the microswitch type and just barely fit but they did work. I had to mount them a bit higher than I wanted to in order to clear the QCX PC board with the terminals on the switches. I also left the key and earphone jacks intact on the QCX board, drilling access holes in the two side panels to keep from having to run more wires over things on the board. The only place to install them otherwise would be on the back panel and that would put them close to the RF output. This way, I seem to have lucked out and now everything is shielded and I have a very clean sidetone during transmit and the RX audio is outstanding!"
"It was a three day project but it's done now and it works very well. One advantage of having it in an enclosure made of double sided PC board, once the lid is on, NO MORE RF OVERLOAD during transmit. Very clean receive audio, no clicks or pops even with the ribbon cable to the display running right over the top of everything as you can see in the pictures."
"I have ordered a 20 meter QCX and when I finally get it, I plan on putting it in the next size larger (Red) 4SQRP box (I do have one on hand) as that one will give plenty of room for everything and even space for a battery pack."
Beautiful QCX-40 acrylic enclosure by Shig JA1XRQ
20m QCX in eBay enclosure by Paul M0PNN
"Finished my 20m QCX apart from labelling the controls. First qso was with UR5LEH followed by IV3ZJJ all working fine as far as I can tell all fun apart from winding T1. I did think the audio was low until I heard a loud cw signal Wow that will teach me to have the volume up so far. The case I used is from ebay UK search for "ST643 5.8" DIY Metal Electronic Project Enclosure Box" though it does come from China. I had to fill the holes for the box feet because they were too close to the board holes. I drilled the holes for the board and used them for the plastic feet as well."
40m QCX in aluminium case, by Nick VK4PLN
"Here is the inside of the case, see the speaker and its amp board, borrowed 5v from the gps socket for it, It came from a Dell Optiplex. It is wired into the switched phone jack so turns off when headphone are plugged in. I did try running it without the amp but has to turn the gain ot so high that the amps started clipping...
I am very happy with the result. The LCD is a good 11mm higher off the main board, I used a set of Arduino Stackable header pins to extend the LCD pins, Lifted it the perfect hight. The LCD is mounted to the lid, 4mm hex nuts are "JB welded" (metal epoxy) to the cover, and lcd fastend to this...
Also using a switched pot for GAIN knob and power on/off..."
QCX-30 by G4GIR
"The enclosure is an RS Pt No 411-6632 TS1 sloping front panel, 58 mm rear height and 35 mm front height.
Have added facilities to select the test options from the front panel and fitted a 3A variable voltage regulator to adjust the power output.
Also fitted the VU2ESE AGC design in series with C21. The AGC is a very useful addition.
I have a small milling machine to machine the enclosure and the engraving was carried out courtesey of my brother (cost me a few beers).
It’s working very well with best QRB VK3AXF @ 16897km."
QCX-30 by Martin G0PJO
"The box is a Hammond 1590BB (119 x 94 x 34mm) that I bought here:
QCX in fleamarket case, by Earl 4Z4TJ
"I mounted the board in a case I picked up at a fleamarket and have been enjoying listening to the QCX this weekend. (some kind of Italian CW contest this weekend...) I am really impressed with the receiver performance. One issue I have noticed is that when a very strong station (i.e. S9+++) comes on frequency I have to tear the earphones off.:
QCX-40 by Georges F6DFZ
"I used a commercial low cost enclosure to house the QCX : https://www.gotronic.fr/art-boitier-beige-g738-6630.htm
The enclosure doesn't need any modification.
About the QCX, the 7805 regulator must be soldered 3 mm lower than the display.
The power supply terminal can be conserved, but you need to solder it with the connexions toward the display.
The gain and encoder axes were extended.
2 push buttons are added to control menus.
A DC socket, micro fuse and switch are added.
Finally a key from QRP Guys was fitted on the enclosure.
Serial number 881 in Heathkit-style case by Barry NF1O
"Thanks for a great Kit. I finished build yesterday and had first QSO wit K1DW this AM
Here are pics for builders page. I found the Heathkit looking chassis a few years ago and it finaly found a use."
40m QCX by Malcolm EI8FH
"While waiting for my 40m QCX transceiver I followed all the emails in this group and learned a great deal.
Got my QCX built and aligned without any problems ,thanks to the superb instruction manual.
I had some cheap rotary encoders in my junk box so I took one apart and removed the O ring to give
smooth VFO tuning as I do not like click step VFO tuning. Added a simple LM567 tone decoding circuit to help with zero beating the received signal .
Only problem I had was when I did not notice high SWR due to a bad antenna connection resulting in high SWR.
It was too late when I saw and got the smell of smoke from my QCX !!
I had to replace final transistors Q1,Q2,Q3, as well as Q4 and Q6, thankfully the QCX is now working 100%.
Have it in an aluminium box 120mm x95mm x57mm to match my SW-80 and external VFO for my HW-9.
Thank you to all who posted about their experiences with the QCX, it certainly helped me a lot."
40m QCX by Boris 9A2GA
QCX-20 in Eurocard case by Matthias DD7NT
"Finished my QCX #1002 today and made the first QSO with Peter DL6DSA. The only problem to fix was L5 (cut off during soldering?). Adjustement went fine. I used a standard EURO case 160 x 100mm. This allowed to add a second PCB with a stepup converter. Gives a stable voltage of 14,8V so I have a bit over 5W with input until 10,8V (PB accumulator for /P operation). Does not make any unwanted noise when screened. For the display and the processor I made 2 separate 5V supplies. There is also some place for further enhancements. Will add SWR measurement and display via the 3 LEDs at the front. An AGC would be also nice.
Many thanks to Hans for this wonderfull toy."
QCX-40 by Tony EI5EM
"40m QCX in case which I purchased from Farnell and engineered to fit."
QCX in special case by Michael DG8YP
QCX-40 by Mick M0GWD
"No issues at all with the build thanks to the excellent instructions - the QCX works fine with 4.5W Output at 13.8V and 3W at 12V.
I have not needed to carry out any modifications other than bend flat the LCD tab above L2.
- I built my QCX No. 693 into a Hammond 1590XX cast alloy enclosure - 145 x 121 x 39mm (5.5" x 4.5" x 1.5").
- I used the plain alloy version - not coloured (therefore no coating to chip or scratch).
- The enclosure alloy material is really nice to file, drill and tap - recommended.
- The PCB complete with display and all controls and sockets are mounted in the box part of the enclosure.
- The display remains as-is plugged into the PCB.
- All wiring is therefore in the box with no flying leads.
- Aesthetically it looks nice because the sides slope inwards towards the front panel.
- A slide Off / On switch is installed on the left-hand side.
- I fitted larger matching knobs - Gain is 22.9mm Type A02 and Tune / Step is 27mm Type A03.
- The Voltage Regulator was carefully bent over in line with the PCB and attached with a small bracket to the enclosure.
- The decal is just a mono laser print, created with a DTP program - I used Serif PagePlus.
- This is protected with a 2mm thick clear acrylic sheet, fixed with M3 countersunk stainless screws fitted into tapped holes.
- This leaves the box lid free to become the rear panel.
- An old TS-120 bail, bought years ago via ebay, is modified and attached to the rear panel.
- The bail was cut in half, a section removed, and a small piece of fibreglass tent pole used to complete the job.
- The bail also makes a useful carrying handle. The two rubber feet prevent the QCX from sliding about."
QCX-20 by Fabrizio IZ0HCC
"I changed the flat pin connector with more longer."
QCX-40 by Leo PA1LDB
QCX-40 by KE0GYC
"I've finally got my QCX up and running 100% after replacing a few components I broke in assembly. Thanks to Hans for such an awesome little kit to learn CW on! I've got it in a little Hammond box, and I've wired up a MicroUSB connector to the 4 GPS pins - I've got the QLG-1 in a separate enclosure wired up to a regular USB connector so I can use a common scroungeable USB phone charging cable to connect the two, and I've got Anderson Powerpoles for the power connector. All together, I'm pretty pleased with how compact it is! If I could do it over, I would get a slightly larger box though. It was really cramped getting all the connectors in, and I actually had to trim the corners of the board in a few places to get it to fit around the posts the screws mount into. Attached is a picture of the completed setup (Yes, the battery is overkill and larger than the radio itself, but it was a 6Ah battery for $35 on Amazon, so I couldn't resist. Construction is definitely a little rough with undue reliance on hot glue to hold connectors in place, but that's par for the course with me - I am slowly improving though, and my next kit should be a 30M QCX in a bit larger box and (hopefully) better build quality!"
"The Hammond case was the 1591GSBK on Amazon. It was a bit too short to comfortably mount the controls off-board, and as I mentioned, the pillars for the screws impinged on the corners of the PCB, but after some trimming I made it work."
QCX-40 by Rick JI1HSV
"I did heat sink the PA FETs. I used a small square heatsink that is usually used on a cpu chip and fastened it to the bottom of the case with an L bracket and then made a 'shroud' out of 0.2mm copper sheet to hold the transistors in place. The 5V regulator is heat sinked also.
"The front panel was done like the rig I'm building laminated photo paper and punched for the holes.
"You will also notice an extra button on the front. The perf board can be seen on the side of the case in the photos and the attached schematic show my pulse 'extender' / double pulse circuits. I think the double pulse length is a bit long but I didn't know what your sampling rate was. You may also notice I had to use relays as I hadn't seen that you had a 10K resistor to ground!"
QCX-20 by Antiono EA4LE/KC2HAX
I am happy to report on another QCX (#2332) up and running, mine is for the 20 m band and hence didn’t have the chance to test it on the air yet as by the time I arrive home in the evening during weekdays the band is already “closed”. The only exception being the folks in the digi modes around 14.076 MHz, thanks to them I know the receiver is working well :)
I really enjoyed the construction and the smart foolproof alignment procedure. Thanks again Hans!
I measured the output power with my scope and a 50 Ohm load. Using a 13.8 V power supply the output amplitude is 45 Vp-p, so 5 W as per the specs :) I also tested it with a freshly charged lead-acid battery (12.7 V) and at this voltage level power output is 40.6 Vp-p, about 4 W.
I used the 17m capacitor values in the LPF in case I want to try it in the 17m band. With this filter second-harmonic attenuation for 14MHz is 35dB. As max power is 5W (see below) this makes the rig compliant with regulators requirements (30dB attenuation up to 5W output power)
QCX-40 by Kim DS1NSG
40m QCX in Maplin instrument case, by Richard G0ILN
"What a fantastic little radio the 40m QCX is. Mine went together without a hitch. I did find that the main Transformer T1 coil kept springing open whilst trying to place the wires through the holes in the PCB , in the end I resorted to smothering the coil in super glue. That fixed it! Thank goodness I did not have to modify the number of turns or I would have been in trouble. Running from my PSU I am getting about five watts output. I have mounted the LCD module upright using 90 degree header pins it worked out fine except the screen is upside down! So the PCB is mounted on the roof of the Maplin ( Code KC61R) instrument box."
"I fitted binding posts to the board for all the ancillary wiring. The drawing of the transformer T1 winding was a god send to me as the wordy explanation just confused me. Thank you Hans, your QCX is a game changer… Whats next?"
Now, for something completely different: QCX by Al WD4AHB
"Now, for something completely different....QCX in a 1992 Crayola crayons tin! I'd had this tin for years and recently used it as an enclosure for a U3S kit while awaiting a 'official' QRP Labs case. I decided to see how the QCX would fit in it. I like the idea of having a little room for it to breathe and possibly add some heat sinks to the PA's for WSPR duty. It sort of has an Atwater-Kent feel to it."
LEGO QCX, by Anthony (UK)
"I extended the buttons by purchasing 19mm 6*6mm push buttons so you can push them from the side for access, they have lego colour codes to match.
The Technics was used for air cooling.
I changed the power system to receive banana power plug inputs.
I used a 3 metre whip and threw some magnetic wire over my house and tied it to the end of the whip, signals received on 20 m!
I bought shaft extenders for the gain knob and rotary encoder and hacksawed 2 6mm diameter aluminium shafts for the two extensions."
QCX-20 by Rick VE7TK
I built my 20 metre QCX rig in late December. Construction and calibration went smoothly using the excellent manual.
To test the rig I called CQ and had QSOs with New Mexico (2,099 km), Finland (6,866 km) and Ogasawara (8,139 km). Not too shabby for 3 watts! (The antenna is a 3-el SteppIR at 15 metres above ground.)
Next I had to figure out how to house the rig. After reviewing the many possibilities in the Builders' Gallery, I finally decided to use the box described by John (PD7MAA). I found the appropriate box at Banggood.com (Part #1211844). It took about a month to get here BUT it is, in my opinion, a perfect case for the QCX.
I've put together a small write-up with some photos. It's on my website.
QCX-80 by Peter HB9BAZ
Now i have finished building my QCX-80m transceiver.
All setup and testing was successful first time!
At last, I have built it into a Alu-case, (30x100x160mm) and the box looks very nice!
Thanks again for this nice kit, next I will do some tests on air, and at least I will use it in the Swiss national mountain day contest!
QCX-20 by Loyal W4LAS
"I used the case first suggested by John, PD7MAA. A connector was added for the GPS module and since I didn't want to lose the straight key I added a small hinge pin in a press-fit bushing to operate the microswitch. I extended the two control shafts by putting straws on them and filling with epoxy. The two button shafts are a couple of connectors left over from assembling an IKEA table. I used the BNC connector that came with the kit because I found putting the right size washer between it and the case solved any mechanical stress problem. Having an Elecraft KXPD2 paddle for my KX2 transceiver, I made provisions to be able to attach it to the QCX also. I added two transistor switch circuits to put the full rail voltage across the paddle contacts because they weren't being reliably picked up by the microprocessor.
So here's the sad story. When I first connected the GPS module I really didn't understand the admonition not to connect it if you're not in Beacon mode. I was in CW mode and the QCX started going nuts and unfortunately at the time I had the supply at 15 volts. Within a few seconds it was drawing two amps and there was smoke emanating from the case. I found that one of the BS170's was cooked and the Q6 MPS2907 was also shorted. I ended up replacing all of the BS170's for good measure and replaced the 2907 with an MPS 751. The nice thing about the aluminum case is it is such a tight fit, I was able to arrange for the flats of the output transistors to press against the side of the case with heat sink compound applied."
QCX-20 by Thomas OE7ANT
QCX-40 by John WI6P
"I recently completed my QCX 40 project and after torching Q6 and Q2 by plugging in my GPS when in CW mode and with no antenna attached (a common occurrence it seems), I have it working beautifully. I decided to use a regular U2S case with VFO/Sig Gen front and rear panels for the housing, and you can see the results in the photos attached. For the front panel (see photo 1) I mounted the R pushbutton in the upper left existing hole, and the L pushbutton in the lower left ("Select") position. The encoder is mounted in the lower right hole, and I mounted a small 5K log taper pot with power switch (Digi-Key PN CT2215-ND) in the upper right. The LCD display mounts normally, and I used two 6" long six-wire female/female breadboard jumper wire assemblies to connect the LCD to the QCX. For the rear panel, in addition to the existing antenna, power, and GPS/Prog connectors, I added two 1.8" stereo phone jacks, one for the keyer and one for audio. These are located adjacent to the GPS/Prog DB-9 connector, and must be carefully located so that they will clear the sides of the lower and upper case halves. I mounted the QCX board to the rear end panel using only the BNC connector (although I did put the four standoffs in the board to provide support, they are not fastend to the lower case half.). It is located such that the board fits perfectly in the case, however, this means that the rear end panel is installed "upside down" compared to the front panel. There is sufficient clearance to mount the power connector and to use the GPS connector (see photo 2). I use 6" or 8" male/female breadboard jumpers to connect all the remoted switches, encoder and pot. I snip these in half and use the connectors for easy installation and/or removal of components if necessary. You can see this clearly at the lower left of the last photo...look for the red, orange and brown wires connecting to the volume control pot. Also, to fit the upper case half over the volume control/power switch, it was necessary to file down the extrusions on the inside at the front of the right half of the upper case. There may be smaller diameter controls available that would avoid the need for this surgery (none of which is visible from the outside), but this works fine too. Oh, and one final comment: my L5 also broke and I didn't have a replacement available. I took a 1/4W 1M resistor and some left-over toroid wire and wrapped 15 or twenty turns or so around the body of the resistor and soldered it to the leads...it works just fine (you can just see it if you zoom in on the last photo)."
QCX-20 by Steven G4EDG
"I replaced the 12mm spacers under the board with 6mm ones, and increased the height of the LCD by adding 6mm spacers to the existing 12mm ones. I also needed to replace the short 0.1inch connector to the LCD with longer ones.
Thus the total height is still 38mm, ideal for fitting in the box used by PD7MAA....I used the extra space above the PCB to accommodate the encoder and AF gain control in a more pleasing position...the three buttons are left and right as per the standard QCX, the centre one is wired in parallel with the encoder push button...a lot easier to operate.
I changed the blue LCD for a green one, not because I didnt like the blue one, but because the green is a negative type (or is it a positive?) This works really well in bright sunlight when the LCD backlight is switched off, this saves 20mA from a total receive current of 100mA...great for portable work.
All the connectors were salvaged from a scrap PC.
The slide switch next to the BNC socket switches in an 18pf cap across the main winding of T1, changing its resonant frequency from 18 to 14MHz"
Rotary encoder dimensions
Someone was asking about rotary encoder dimensions, to help with designing an enclosure for their QCX. The image below is a dimensional drawing of the rotary encoder supplied in the QRP Labs kit. CLICK for larger version.