3D printers and the uBITx go together

Doug K4DSP hesitates to say that that is µBITx is actually finished, as he keeps thinking of stuff to add to the hardware and firmware! But the cover is on and he’s making QSOs.

Previously Doug had only used his rig on CW, but he used a 3D printer to make a mic case and got it wired up.   His first SSB QSO was with S51DX.

Doug is pleased with how well the little radio “hears”.   While drafting his update for the BITX20 IOGroups list he was listening to G0EVY on 40M SSB who was booming in.

Doug has yet to install the AGC board so he finds the static crashes are “pretty harsh”.   He says it reminds him of his old Heath HW-16 in that regard.

The mic case  design was sourced from Thingiverse:

It uses the mic element and microswitch that were included in the uBITX kit. He printed it with black filament and then rubbed some white paint into the front to give it some “character”.

Doug printed the uBITX case from here:

He only used the front and rear panels.  He designed his own middle section to add mounting holes and a baffle for an internal speaker.   He used FreeCAD to do the design.

Doug calibrated the frequency against a 10 MHz GPSDO. Then, based on advice of others, he used a PC audio spectrum analyzer program (Spectrum Lab by DL4YHF) to adjust the BFO frequency. That worked a treat, and he’s really happy with the way the audio sounds now.

He concludes, “It’s just a very pleasing little radio”


An interesting µBITx

Daniel Conklin says “I guess I’ve had enough fun with this radio and now it’s time to move on.”

He is selling his UBITX v3 which is built into an Apache case.  It might inspire others to build their rigs into these clamshell like cases.

There is space for the mic and a battery pack to sit when the case is closed. The mic and PTT switch are mounted in an old BaoFeng mic housing and it works well.


Cheval Case with JackAl board installed

Rick KN4AIE installed his uBitx V3 in a Cheval case (see previous post) and later added the JackAl mod.

Everything fit nicely.  The case is all aluminium and easy to work with.  It also provides very good access with both top and bottom covers and front and back  panels removable.  The case is a little pricey, but very nicely constructed.

Rick ordered his case from an eBay seller.


Some interesting cases

Finding a case for your µBITx is easy … finding a good case is more tricky.  Many use one of the many µBITx cases sold by Sunil.  Others have their own favourites

Two new suggestions from Jack KZ5A are worthy of a second look.

The Cheval case illustrated below can be obtained in both steel and aluminium versions (we would strongly recommend the aluminium version).  This case will have to be imported from Thailand.  It is also available on eBay.  It is a very nice looking enclosure, reminiscent of Heathkit enclosures from the 1970s.

The Circuit Specialists aluminium instrument enclosure is a not quite as good looking enclosure, but at a very good price ($US21 excl shipping).

Mike ZL1AXG purchased several aluminium cases from aliexpress.com that are intended to house stereo amplifiers.  This particular model (Breeze 2207) is 228mm x 70mm x 215mm.  A good size for incorporating a few additional circuit boards alongside the µBITx main board. These cases are precision made and look really nice.  They can be acquired for around US$15 each (plus shipping – that will be more than the cost of the enclosure).  Mike has yet to transplant his µBITx into the new case.


Amateur Radio Kits case construction pics

Joe KD2NFC is building his new µBITx into one of  the cases from www.amateurradiokits.in.   In this case it is for use with the 5″ Nextion screen.

Joe says, “These cases are awesome and really add to the fun and creativity of building the uBitx. I am still waiting for the 5” LCD but here are some images of my progress.”


VU2POP cabinets – swap out bezel to upgrade from 1602 to Nextion display

Pop  VU2POP shared pictures of his homemade ubitx cabinets.  The design involves a common cabinet for both the standard manufacturer supplied 2 line  1602 LCD display as well as the 2.8″ TFT Nextion display.  Pop says “You need to change out the bezel.”   This is a really good idea.

He supplies the complete cabinet, fixtures, microphone, microphone and PTT sockets,  associated PCBs, and the speaker, fuse holder, fuse, heat sink insulation kit, heat sink compound, tags, screws, usb cable panel mount, knobs, folding feet, glue,  and a USB to rear panel connector cable to fit on to Radiuno.

This is similar to his earlier cases, except this case will have common front panel bezels for 2.8 inch TFT & 2 line LCD.  Just change out the bezels!  Constructors can build the stock  µbitx to get going and then upgrade to a 2.8″ TFT display at a later date when they have the basic rig working perfectly.

At present these cases are only available for VU amateur operators.

Complete kit and kaboodle

DX shipments will be available at  www.radiokart.in from Feb 2019.


G4USI Go Box

Several constructors have put their µBITx in a Go Box for portable/emergency use, but this is one of the best looking results yet.

Daimon G4USI has used a 3D printer to produce a very professional looking front panel.

This is a re-mix of DU2RK’s uBitx Case, and the re-worked front panel of this case by AngelDMercedes.

Daimon wanted a different case, one he could build into an existing flight case to create a Go-Box for HF.   He remixed the ideas above to create a case which fitted his flight case perfectly, but with every control and function sitting on the top panel.

In the strictest sense this is not a full case. It is a top and two vented sides. There is not a bottom, front or back panel –  the flight case provides the structure.

On the top photo you can see a 12v 5a power supply and mic in the space to the left of the rig.  Daimon now has a home-brew EFHW multi-band antenna, SOTA Beams ATU and miscellaneous portable QRP operating items in the right hand compartment.   Everything, in fact, that he needs for portable QRP HF.


New build uBITx with Nextion screen

Jim Reagan W0CHL has made a compact build using a Nextion display.

He used a Context Engineering (Fry’s Electronics) case. It’s a tight fit and not for the beginner. I had to “mill out” (dremel) areas for the stand offs (they are nicely recessed on the front panel).   He also chopped off (with a bandsaw) off back 1 3/4″ of the case. It’s using the 3.2″ Nextion display and has a quiet  24 volt fan to keep the finals cool.  The final size of the case is just 3 x 6 x 6 1/2″.



VU3SUA case documentation

The µBITx case from Sunil Lakhani VU3SUA  is popular with constructors based on its value for money.  However, many find it difficult to find wiring guides for this case.    It is documented at various places by VU3SUA.  Sunil Sankaranarayanan VU2MTM has downloaded all of the photos and these are collected together.

[wpdm_category id=”vu3sua-case-construction-help”]

[wpdm_package category=’vu3sua-case-construction-help’]


Tips for building into VU3SUA enclosure

Dave, N8SBE completed a build of the µBITx last night in one of Sunil’s µBITx enclosures, and he has helpful observations for others using this case.

Front panel PCB

In spite of the pictures, the main board must fit OVER the front panel PCB, so that you can mount the LCD display up close to the front panel.

Dave put vertical male pins on the ends of the front panel PCB, which meant that there was insufficient clearance.   If you want to put male pins on the front panel PCB, you should use the right-angle ones (and then the mic connector will be a tight fit against the chassis mount four-pin mic connector, but I was able to just make it work).

He ordered a Dupont kit of male pins, female sockets and housings from Amazon and a suitable crimp tool:


The crimp tool works fine, but Dave spoiled a few female sockets before I got the hang of it.

If you are crimping female sockets on the ends of the original wires that come from the Relimate sockets on the µBITx (trim them to 8 inches first, then you can use the extra for other wiring, see below), then it seems the wire gauge is about 22 gauge, but the crimp die in the centre of the tool that is marked for 22 gauge is too large and won’t crimp the wire properly. He ended up using the crimp position for the smallest wire size, and it worked fine.

It is also important to insert the female socket in the tool first (Dave found that by clicking the tool 3 clicks it closed the jaws just enough to make it easy for me guide the socket into the tool), then push the female socket in far enough so that the box that encloses the male pin is completely outside the dies on the back side of the tool.

Then lightly pressing the handles to keep everything in place, insert the stripped wire into the back of the female socket, and crimp.

The wire should be stripped only about an 1/8″ of an inch, and the insulation should be inserted into the back of the female socket such that the bare wire bundle is crimped with the smaller crimps, and the insulation is held by the larger diameter crimp at the back end of the female socket.  If you strip off to much insulation, you will either fail to get the insulation into the back crimp, or you will force wire into the female socket area, and that will interfere with the male pin when it is inserted.  If you’ve done everything correctly, tugging on the wire shouldn’t make it come out, it will seat correctly on a male pin, and you should not have to resort to soldering anything.

Soldering crimp joints is a BAD idea, not only because the clearance in the female connector bodies is very close, but the solder that wicks into the wire bundle will stiffen the wires past the crimp, and create a stress point that will eventually break the wire if subjected to vibration and movement.

Dave ended up using Dupont housings/connectors on the Audio, Digital (both 8 pin), Mic (three pin), Volume (three pin), encoder (4 pin) and speaker connectors (2 pin). 

When you cut the ubitx supplied analog and digital wire bundles to the recommended 8 inches, you end up with enough left over that you can make all the other front panel connections with using the left over wire.  You can even select the appropriate colours, as documented in the wiring instructions on the HFSignals website.

Small PCB for Encoder

Dave completely missed that there was a small PCB board included for the encoder switch.  He ended up tack-soldering the ends of the four-wire bundle coming from the front panel PCB to the actual switch pins.  It works fine.

Wiring the volume control

Dave somehow got the wiring backward on the volume control (hi end vs. low end), and was “surprised” by a VERY loud noise when he first powered it up.  If you mount the control with the soldering tabs on top so you are viewing them directly when looking down at the rig with the top off, then the correct colours from left-to-right (with the front panel closest to you) are yellow, orange, green (given the wiring colors shown in the wiring section on the HFSignals website).

Power supply wiring

The power supply wiring was an issue, due to the power on/off push-push switch.

It is NOT meant for soldering, as the tabs are practically impossible to solder to (don’t know the material, but it does NOT accept solder), and the body melts in an instant. The tabs are meant to be used with push-on tab crimp connectors (You can find suitable ones at the local auto store in the electrical section).

Dave still wanted to use the PCB board, so he ended up inserting the power switch tabs through the board, pushing the auto tab crimp connectors on, and then tack-soldering the crimp connectors to the board.Ugly, but effective.
Before Dave figured that out, though, he had partially melted and loosened one of the power switch tabs.   
The rest of the power PCB board wiring went OK.  Dave put a three pin header and connector on the end of the board going to the ubitx supply wiring.  Originally he used a right angle male header, but discovered that this interfered with the mounting bracket (and likely the board when installed) for the digital interface PCB.  The solution was to bend up the pins from the board at a 45 degree angle.  Ugly, but effective.
Check the actual wiring of the DC power plug.  The diagram supplied with the enclosure kit shows using a pin for ground that was found to have a no-connect.  The other unused pin turned out to be ground (the sleeve on the DC plug). 
Double-check your wiring in this area with a multimeter to ensure that 1) You have continuity where you expect it from power supply to the µbitx board, and 2) You haven’t inadvertently reversed anything or shorted anything out. 
Don’t forget the chassis ground to the solder tab that comes with the SO-239 socket.

Wiring up the Antenna connector

Dave used the supplied antenna 2 pin connector and wiring that was supplied with the ubitx, but it was not possible to keep it only 2 inches long in this enclosure.  It’s more like 4+ inches. You could use a short piece of RG-174, instead, to lessen any possible pickup of birdies.

Digital interfaces on rear panel

Dave hasn’t used the digital interface for the back panel or the front panel RX/TX LED.