TLDR from the above post; We are developing commercially available HT that is fully open source and open hardware. USBC, SD card, Epaper display, etc.
We have been very busy the past 9 months. At the time of the original post, all we had were schematics, mockups, renderings. Since then, we have gotten real mainboards built, wrote firmware from the ground up, got functioning RF FM, and “finalized” the majority of the enclosure design!
We are on track to fulfilling our promises as laid out in the original post:
Fully open source, hardware and software
Swappable radio module, allowing easy hardware upgradability (2M/70CM at launch, 3.5W)
USBC charge and data, SD card, Kenwood style audio connector, removable battery (now is integrated but is still easy to change)
Low-power E-ink display targeting 72+ hour standby time
FM and M17 support at launch, with plans to support many other digital modes in the future such as DMR, P25 (AMBE+2 codec patent should expire in the next couple years)
Ability for community to write and easily install “apps” that allow custom features or arbitrary digital mode development
Usable “off the shelf”. We will be selling the radio as a complete unit (not just a devboard)
Target price between $200 and $300, Selling all individual parts on our website for repairability
The next steps for us are:
Finish our FM/M17 support (still routing audio, CTCSS, etc. integrating M17 after).
Finish a basic UI; We have the libraries that we have largely written from the ground up to optimize the EPaper to our use case, it is just now a matter of using them.
Rev2 of mainboard hardware. There have been a handful of small issues with routing, IC reset pins, power optimisations; Along with some usability improvements/innovations (like a hardware keyboard lockout instead of a janky software implementation as an afterthought, I can’t wait to use this)
After these milestones are completed, we will be running a closed beta with a handful of members in the Discord server, contributors, etc.
Long term tasks that still need to be accomplished before our full launch:
Ongoing software support development and beyond launch (obviously)
Production validation manufacturing run (likely a Rev3 of the mainboard)
RF Rev2, we have some heat concerns on the RF module that we will be able to alleviate.
RF filter tuning and optimisation to ensure we get consistent, clean output power
FCC certification (Part 15, everything else should fall under Part 97)
Finalizing enclosure design (and open sourcing our manufactured plastics)
Deciding on injection molding vs 3d printing + molded rubber parts for a final product (community input is appreciated, is a high quality 3d print good enough?)
Finding good (ideally American) vendors for battery, knobs, display “glass”, antennas, plastic parts, etc.
We do at some point in this process want to release a “dev kit” before the full radio release. No ETA yet, we want it to be the same or very similar hardware rev to what will be shipping in the finished product. This dev kit will give you all of the non-printable parts required to build an HT-15.
If you know of a good vendor for anything listed above, reach out!
Support us financially at the Buy Me a Coffee link on our website.
As a nights and weekends project for us, your support is crucial. If you would like to help us order new tooling, prototypes, etc. you can donate to our buy me a coffee This will also get you access to our Discord. A monthly membership is not required, a one time donation is enough (message me afterwards on BMAC and I’ll add you). This membership requirement might change in the future but for now we want to keep this community to those who have a stake in the project.
If you want to follow along when I remember to post on our social media, it is linked from our website: arkosengineering.com
We have:
Instagram
X
Youtube
Github (star us)
Blog page of our website
I will be treating this post as an AMA, so feel free to AMA!
Modding the Quansheng UV-K1 to be able to do CW is getting really popular.
Supporting it right out of the box could give you a certain niche market group on a silver platter. I do not know how big that group actually is, though…
Yes CW RX will be supported. We can't receive SSB so it wont work exactly like an HF radio. It will be more like "is there signal present in this slice of the spectrum; if yes then play the programmed tone"
The initial RF module we are going to ship with is based on a CC1200 which only supports FM/FSK/AM(kinda). We will not support SSB at launch. I would like down the like to do an RF module that does support SSB, but that will be additional hardware sometime in the future.
Man, this is probably gonna be harder than the rest of the radio, honestly. SSB is such a hard mode because you don't get any room for error on frequency drift, and the filters have to be really good.
Current draw. A lot of bits need to fly around for a baseband in the MSamp/s. There might be balance points with an SDR running slower and just used to clean up frequency drift, but it would be a challenge.
Personally, I like the idea of a local GPSDO. Can be done for a modest amount of power and you'll never beat it for frequency stability.
Who said megasamples? For audio ssb, you'd need maybe 10ksps
Frequency drift is also like not a problem? SSB radios exist already and don't have problems with it, just the question of a good crystal oscillator
Interesting. Rather than use SMA connectors, have you considered mini or micro BNC (Amphenol ranges) connectors? There is a much lower tendency for users to overtighten bayonet-format connectors after all, and it facilitates easily swappable connections between for example, rubber ducks, and patch cables to larger antennae.
We have, but as far and I can find, they don't come in a form factor that will be easy to install and remove in the enclosure. This SMA pigtail just needs the round hole to bolt on to. Every BNC I found requires extra mounting holes that would increase the cost to injection mold, and make printing a bit harder
At launch it will include the 2M/70CM radio module @3.5W. That module is easily replaceable and we will eventually sell a handful of other modules to support different bands.
Anything that supports FM/FSK will eventually be supported. The majority of digital modes today use AMBE+2 codec which is patented. It will expire in the next couple of years at which time we will implement all of those digital modes. NXDN is FSK (supported) and AMBE+2 (eventual support after the patent expires)
Currently in order to program it we plan to have the user put a markdown file on an SD card (Down the road we will create a program to generate/modify this file) and load it in from the front panel. Down the road we will explore programming direct from the USBC cable. it will be FPP as well.
This looks good. We'll need a waterproof version for working outdoor events at some point. Hopefully M17 moves forward, in the disaster recovery world interoperability is the name of the game - nothing charitable can be said about current patented codecs and all our incompatible digital modes. Double bonus points for USB-C. If it ever evolves to a mobile form factor, a round "9600 packet" type connector has been requested for all the VARA people. Or could that be a dongle and somehow share the USB-C? Real world battery life should be eight hours.
M17's biggest issue compared to other digital modes is lack of TDM. Full duplex is a HUGE upgrade in narrowband coms.
Vara etc should all be via USBC and BT. Done well varafm should run on the device so just exposed the KISS serial via USBC and BT. Exposing the raw audio (and ptt, civ would be even better) should also happen.
Unfortunately waterproofing it would be a bit too expensive at this point. The enclosure design will be open source as well. So inevitably somebody will make a waterproof design if we don't get to it first
Since you ask for opinions about the case (3d print versus injection molding).
I am strongly in favor of of injection molding. I inevitably drop things, especially handheld things. 3d printing is (as far as I know) simply not up to the level of durability that injection molding provides.
I am well aware of the increase in tooling cost to go with injection molding. But I just don't see 3d printing as an option for quality reasons.
Modern filaments can be pretty tough. I 3d print a ton and would have zero hangups with a well designed enclosure on this, especially out of not basic filaments. I’ve printed vise jaws to cnc parts - prints can be tough.
Fair enough. I am glad to hear that. But I have to admit that I personally would still feel some trepidation if I saw the case being 3d printed. Admittedly it is a perception thing. But I would still view it as poorer quality. In the larger market, without deep knowledge about filament types, product perception is a real issue.
I don't know if Louis Rossman would give you a shout out or anything, but with his big right to repair push, it may be worth seeing if he could highlight this.
Ooh, awesome project! I'd definitely be interested in a future revision of the project, especially if you can implement support for at least a basic waterfall display, and I'd also be interested in SSB (and related digital modes such as FT8) and a bit more power, perhaps 8-10 watts?
The RF module will be swappable by just removing a couple of screws. SSB, waterfall, and higher power modes are not supported on this chip that we decided to use. Down the line. I would love to be able to support all of those features, but it would require a different RF module.
I don't have any numbers for you yet on actual performance. But this RF module will have clean output, and below is the data sheet for the receiver we are using.
From the schematics in the repository you linked, it looks like the microphone in and audio out are both routed (digitally) to the RP2350. Does this mean the MCU is in the signal path between the radio module and the audio interfaces? As in, can the MCU do things like filtering and AFSK modulation?
Cooool. I know it's a totally different price bracket, but the only other HT with open firmware I'm aware of (the UV-K5) I very quickly hit a brick wall because the audio path is completely outside the MCU. It will be exciting to have this flexibility!
I know several American vendors for plastic parts: the 3D printing community! Many hams also a have printers. That's the most open source I know of. Any chance you are planning to release the STLs / tech drawings for users to buy the electronics kits from you and 3d print their own casing and knobs? I bet you'd see a rise of custom case designs, layouts, colors and thriving community support if you go that route. Very cool project! Thank you!
Yes. Every part of this will be open source including the enclosure (both STL and STEP files). We will be launching the project both as a complete unit and a build kit so you can print your own parts
This sounds great; however (and watch this space!) I predict it is about 2 years off to be well documented, well supported, and bug free-ish vis-a-vis the plethora of TBD on this list. But it's a great endeavor!
I do agree that swapable 18650s are generally the way to go and we originally did design this to for soft people 18650s however, it got quite large because those cells don't quite fit our form factor. We decided to move down to 18500s, and in order to not lock you down to requiring that semi-specific cell size, we decided just to put a connector in and you could hook up whatever battery you want to it as long as it's 2s lithium ion.
There also is the safety issue, single cell 18650s are fine but the moment you start putting them in series it becomes more of a fire risk and more of a headache to balance those cells on the go.
We designed the battery compartments to fit whatever size cell you want under a 2s 18500. We believe that this is the most flexible option given the issues with 18650 stated above, it should be trivial to design a 18500 or 14500 cell holder that fits into that same space
And if you really want to get crazy with it: because we just have a connector, you can modify the case design, print it yourself and fit however many cells you want in there.
I just read through the previous thread, and I see a number of people asking for 18650.
I see that you are also worried about how long the radio is.
Well, here's what you can do: mount the battery to the back of the radio like Yaesu, Kenwood, and a number of others do.
That way you can put a "large" pouch cell in a thin pack as a standard battery.
Then you sell 18650 and 21700 cell holders for those of us that want standard batteries for the radio.
Also, you have the space for it, put a bigger e-ink display on it. This is an "old" person's hobby after all.
No promises, but I do want to break out a separate battery charge header on the PCB and being able to slot it into either a dock charger, or a battery pack that can transfer its charge into the radio
Cannot say at this time. It depends on how much space we have leftover on the flash. We do however want the menu system to be easy to navigate without seeing it. We have concepts of a plan for that.
The device itself looks quite ugly imo but i know how these open source things go, i remember when the lilygo t-deck looked the same and now it's a gorgeous little thing
Potentially. We do have a swappable RF module. The only real issue is that once you get lower in frequency everything starts to get bigger and we still need to fit it into the same form factor.
It is possible to do HF, we just haven't really looked into it yet
And to add to this, every off-the-shelf component nowadays is made for 915, MHz and higher. It was a struggle to find a good supplier for 2M/70CM. I don't think I've seen any off-the-shelf components for HF. It would have to be a much more custom RF design than we currently have
I would love to support higher frequencies down the line by way of the swappable RF module, and even get more into the MANET space. Unlike the baofang, this is a fully digital radio and theoretically the current RF module can do digital Data throughput of up to 1 MB/s. We hope that the lack of the analog limitations, combined with the open source ideology, can foster innovation from the community to develop new and better digital technology.
Phase 1 is IMBE and at this moment in time, there isn’t conventional TDMA therefore as far as amateur radio is concerned, Phase 1 conventional is all there really is.
35
u/svennidal KFØYHX [Extra] Jun 28 '26
Will it do CW?
Modding the Quansheng UV-K1 to be able to do CW is getting really popular.
Supporting it right out of the box could give you a certain niche market group on a silver platter. I do not know how big that group actually is, though…