First Look at the HF Signals zBitx QRP Transceiver

When life gives you lemons, you make lemonade!

by Vince (VE6LK)

Dear readers, it’s been a hot minute since I’ve had time to activate POTA and write about it, and today I tried to activate a park, but a combination of equipment issues and nobody responding to my calls ended my activation. Anyways … when life gives you lemons you make lemonade, and accordingly the activation article is now a radio review article instead!

That radio is the HF Signals zBitx. An SDR radio, it was spoken about at 2024 Four Days In May and it opened up for orders on December 25 2024 – a Christmas present, if you will. Thomas and I both jumped on the ordering queue (two numbers apart, no less) as well as 248 others around the world. I thought to myself “an all-mode 80-10m QRP radio with a waterfall and weighing under 1 pound for under $200USD shipped? SIGN ME UP!” and pressed the order button. Honestly I thought about it for less than 45 seconds once I read the specs. I also thought to myself that it was an “experimenter’s radio” and not a fully finished product, meaning you can tweak it if you wish to dig into the bowels of the code on the built-in Raspberry Pi.

The 250 original orders were snapped up in two days and then the purchase button was turned off on the website. There were some shipping delays from the original date, as HF Signals discovered the Chinese New Year holiday of 3 weeks where, it seems, everything is shut down. I also discovered this with the Morse Tutor Kits my buddy and I sell, and we couldn’t ship product for a month as we could not get parts.

Showing the on-screen keyboard. It also shows the fit and finish of the shipped product. Photo credit: HF Signals

The radio arrived on March 31, about 4 weeks beyond the original estimate, and I was excited to open it up. I mean, who doesn’t like new radio day after all? I was so excited that I did an unboxing and first look video on YouTube and showed off a few quick things about the radio. TOP SECRET – it took me 5 takes to shoot, so it wasn’t quite a first look!

The radio promises much and delivers a lot. It transmits on 80 through 10 meters at around 5 watts driven by a pair of 18650 cells, or your 6 to 9V four amp power supply. It has two microprocessors, one is a Raspberry Pi Zero W and one is a Pi Pico to drive the display. It has integrated AM, SSB, CW, FT8, touch screen, built-in electret mic, built in CW keyer and keyboard, and weighing just 460g / 1 pound including the batteries. This radio seriously has lots to offer especially at the price point.

The author’s radio with a customized faceplate and VFO knob. The triangular slice in the waterfall display is a photographic artifact.

The source code, schematics and 3D print files are all available on a Github, and indeed I customized the front panel and replaced the knob with one that has a dimple on it, if only to spin the VFO more easily.

You must be made aware that I was really excited to get this radio. It has a history of many other Bitx radios before it. But I’m also aware that there’s the old axiom about “too good to be true” so I tempered my expectations. You must also be made aware that I really want this radio to work as its small form factor, low cost and integrated waterfall make it exciting an exciting prospect in my limited fleet of QRP rigs. And, for the record, I have nowhere near the QRP rig count that our gracious host has, nor are they individually named.

Besides all of that, it is the only HF radio I plan to pack for Hamvention 2025 so it’s gotta be right for that trip.

However, the zBitx may be best described as an early release and/or a work in progress.

To mitigate this “in process” part, I’ve been following several times a day and looking for news of firmware updates. I’ve applied two software patches and one firmware patch which have taken me very little time to do. I’m happy to report that each one improves the overall product.

At this time I’ve had the radio running in various test configurations for about 10 hours both in my shack and in the field. It’s not enough [for me] to say it’s been thoroughly tested, but enough to get a really good feel for it. For the record, I did complete one CW QSO but not without much difficulty with keying (see below).

At home it’s connected to my W3EDP EFRW via my LDG AT-200Pro II, and the one field test I gave it was with my 40-30-20m trapped EFHW. A fair amount of my bench and field testing included a dummy load and turning the Drive [power] control to zero to eliminate RF ingress as the source of any issues. I’ve also tried an external keyer with the radio set to straight key mode. I’ve checked into HF nets with it, and listened on nearby SDR receivers to hear what it sounds like over the air.

I’ll describe it here as the Pros,**the Quirks and the Cons.

Things I still have to try include the aforementioned Drok Buck Converter, adding some 0.1uF capacitors to the CW lines, and a 100pF on the microphone.

Things I’ve added/changed on the radio include a face plate swap with my callsign engraved on it, the VFO shaft was shortened by 5mm (side cutters and Dremel tool to smooth it out) which allowed a dimpled VFO knob to be placed on the radio, and I added some 3M adhesive-backed polyurethane feet so that it won’t slide about on my desk. The original 3D Printing STL files are available on the Github so you can modify your own as I did, or you can look at the one created by Toshi JA3IRK of PockeTech. Sidebar: you can see all of the fabulous products Toshi sells on his website, but you may need Google Translate to assist. I have several of his products and they are top-notch.

I’m going to channel my best efforts from The Candy Store(tm) where I help customers to spend their money wisely. First off, I’m going to be that guy and remind you to RTFM or Read The Freakin’ Manual. The excellent user manual can be found on HF Signals website and it’s only 25 pages long so it’s not going to take you all that long to review it, and it will give you a great idea of what the radio is capable of doing. With that preamble out of the way, here’s my thoughts.

If you want a fully working out-of-the-box radio and don’t operate CW, and you recognize that this is a low-cost radio that isn’t perfect, then break out your credit card and get in line and enjoy it for what it can do which is, frankly, a lot.

However if you are someone who wants a polished product, or primarily a CW operator, I suggest you wait until the bugs are worked out unless you have a good sense of humour and/or experimentation built into your DNA.

I’m happy with my purchase, but had I known I’d likely have waited. Then again, it gives me something to write and/or YouTube about so that’s not a bad thing in my world.

I like this radio, a lot. I also like experimenting with things and am unafraid to get under the hood to see what makes it tick. I have some filter capacitors to add and report back. And I have to decide for myself if I’m likely to reverse the polarity on it and want to circuit hack to add a fuse, or just forego that. I also want to try the USB-C PD 9V power cable with my Charmast USB-C PD battery pack as a power source. Oh, and I really want to get a POTA activation in the log with this radio.

As I have more to try, you will no doubt hear from me again about this very versatile radio. Meanwhile watch the progress on HF Signals’ Groups.IO page.

72 and dit dit,
…Vince

First introduced to the magic of radio by a family member in 1969, Vince has been active in the hobby since 2002. He is an Accredited examiner in Canada and the USA, operates on almost all of the modes, and is continually working on making his CW proficiency suck less. He participates in public service events around Western Canada and is active on the air while glamping, mobile, at home or doing a POTA activation. You can hear him on the Ham Radio Workbench podcast, follow him on Twitter @VE6LK, check out his YouTube channel, and view the projects and articles on his website.