UV-K5 is the most hackable handheld ham radio yet | Hacker News Reader

UV-K5 is the most hackable handheld ham radio yet

spectrum.ieee.org

330 pointsBrajeshwar184 comments

Really impressed with the custom firmware people are developing for this radio. The one I am on now is written by egzumer and even comes with a spectrum analyzer.

Unfortunately, the radio itself is about what you would expect from a $30 import. The frontend easily overloads, and the harmonics on transmit are way outside what the FCC permits. Still, as a gateway into ham radio, it is one hell of a value proposition.

> way outside what the FCC permits

Confirmed. And yet it has an FCC ID from early 2023...

https://fcc.report/FCC-ID/XBPUV-K5

The FCC doesn't test the transmitter. The device is only tested to comply with Part 15 unintentional radiation rules (just like any other consumer electronics device).

Have you been able to perform testing? I think the quality of these Chinese radios has actually improved quite a bit over the years, and the reports I see of testing UV-K5s shows them within FCC limits (well within for 2M, closer to the limit for 70cm). The situation is much worse if you transmit outside of those bands, but, well, that's not really what it's designed for anyway.

You have to be cautious with harmonics reports on these radios because a lot of people seem to try to evaluate them with an SDR... and they are pretty much guaranteed to overload the SDR's front end and cause all kinds of intermodulation that people mistake for emissions of the radio.

I wish ARRL still put more testing pieces in QST because it's hard to know what to make of the testing reports you see online. People end up finding all kinds of different results, and I'm sure there's variation between units, but it also seems like there's a big aspect of... random internet people unsurprisingly having inconsistent test setups.

> You have to be cautious with harmonics reports on these radios because a lot of people seem to try to evaluate them with an SDR... and they are pretty much guaranteed to overload the SDR's front end and cause all kinds of intermodulation that people mistake for emissions of the radio.

This is something more people should know. On the most popular USB SDRs even a local FM radio station will have the appearance of transmitting on harmonics, which I know for certain the serious hams would report within hours.

> ...which I know for certain the serious hams would report within hours.

In reality this is a myth. There are very few people who go to this length. And even the serious Hams will need some serious gear (e.g. KrakenSDR) to pinpoint quickly. Lots of Hams take themselves way too seriously. Folks like NotARubicon on YouTube do a good job of calling it like it is.

I’m not sure about where you are, but here the scene is littered with retired electrical engineers, former broadcast professionals, and military comms specialists with tens of thousands of dollars worth of high-end transceivers, vnas, and small antenna farms. And my point was that the guys with serious gear would quickly notice if a local fm country station was actually transmitting in the amateur bands like a cheap SDR might incorrectly show.

Feel free to send over any fines given out by the FCC within a thousand miles of where you are. There likely aren't any any in the last decade or ever, and this is all public record. Hams are great at scaremongering. They're friendly for the most part, but there are always "some people", especially on air.

You may be arguing a different point now? Whether or not fines have been handed out would not be a reliable indicator of whether "the serious hams would report [an issue with an FM radio station] within hours".

I would expect that issues with FM stations' broadcasts would be very rare, and generally not receive a fine even if it was technically a fine-able offense. This seems like a situation where a ham would call it into the FM station and maybe into the FCC, the station would fix it, the FCC would call the station and just confirm that the station fixed it.

Exactly what I was trying to get at, thanks!

Not arguing a different point. If the offense was such that it would be reported then it should be acted upon in some manner. The reality is that a lot of these spurious emissions are not of any significant reason to react which was my implication with the scaremongering reference. The reality is the FCC approves these cheap Chinese devices and even when they aren't "clean" they rarely impede. Yet what you're referring to is these folks, ultimately, chasing down things that really are not consequential to the airspace however it's an all-hams-on-deck scenario to track down said offenders.

Am I glad these folks are out there? For sure, but there's a fine line of being over the top that they often surpass for little reason.

The FCC doesnt do a lot of enforcement, but there is certainly more than zero. I see about a dozen enforcement actions this year here: https://www.fcc.gov/enforcement/orders?page=1

These are mostly violations for transmitting in the FM broadcast band (88-108MHz) without a license.

Just because there are not forfeiture orders does not mean the FCC field agents sit on their ass.

There are a number of technical violations across many licensed services that the FCC finds and organizes resolution. They don’t fine for honest mistakes and failures, only repeated willful violations. You have to be a real jerk to end up with a fine.

In a most boring sense, they are usually component failures or mistakes in maintenance or operation.

I have been involved in several notices from FCC field offices on technical issues in the first half of my working life, some of them pretty awful ideas and yet none of them resulted in fines when cleaned up in a reasonable amount of time.

Even when an errant AT&T microwave transmitter took out the lower half of the 3 GHz band in Detroit for three weeks, the FCC stepped in, confirmed the source, found who was responsible and the interference solved. No fines, no PR, just a days work.

I own a few UV-K5s and compared to superheterodyne the actual RF capabilities of the radio isn't all that great. I own a few Wouxon (higher end Chinese radio) and they aren't even remotely in the same league. I've tried a number of more quality antenna on the Quansheng and they do help. I've even had one where the RF was clearly broken out of the box, so your mileage will really vary on these.

All that being said, for the money and programability, they really are cool radios. Not legal on GMRS, but perform as expected in those bands with a better antenna. Airband on these things is pretty much next to useless though.

Hopefully other manufacturers will follow suit.

  > Airband on these things is pretty much next to useless though.

I am using this firmware: https://github.com/kamilsss655/uv-k5-firmware-custom and receiving my local air traffic very clear.

The original UV-5R had notorious spurious emissions. The slightly upgraded version GT-5R is a lot better about that. There was a test report (in QST iirc) that is linked from the GT-5R page on radioditty.com. I have been wondering whether the UV-K5 has the same improvements that the GT-5R has. If anyone cares, the fairly well regarded Yaesu FT-65R is a repackaged Baofeng with some analog tweaks. Connoisseurs tend to prefer the older FT-60, a heavier and clunkier radio that is still being sold.

And... I just bought one. It's under the threshold for impulse buy to fuel the hobby. Hopefully it doesn't sit in the box for too long, I would love to hack away at it and see what else it can do.

I would love more manufacturers to open up the firmware on devices like these. Leave default safeguards in place from the factory, but allow tinkering.

Cheap, hackable stuff helps get new people interested in radio, especially if it can be managed using tools people might already be familiar with like WebSerial.

People stress about the safeguards too much. If you run around trying to jam gps, airband, or cellular you'll get your pp slapped pretty hard. If you go off and experiment with random other stuff without making too much noise, literally nobody cares.

yea, it's possible to loose perspective on how much people can just go out and do in life, and how after-the-fact most of the systems that prevent it are.

It seems like there is a predisposition to that perspective shift for people who spend all day working on little boxes that are the one area of society where relentless permissions and control are ruthlessly and untiringly micromanaged to high heaven. There's a lot of fatalism that after the fact remedies are impossible if something was done with a computer, even when the actions in question are performed by known parties that comply with legal bounds.

It's not just about getting caught. Many of us hams try to cause as little interference to others as a matter of honour and pride in our hobby.

I just ordered one too, just because of the hackability. (I will likely never transmit with it, since I already have a radio with a better radio.)

For you and anyone else, make sure you order a programming cable. The baofeng one works for the UV-K5. And when you go to use it, be aware that you’re going to have to press it into the radio far harder than you think. It will make a loud click the first time, and save you hours of troubleshooting!

Heh, good to know! I guess they're using ports that are just a bit too tight from the factory.

Bit of a shame it requires a proprietary programming cable via the audio ports. The UV-K5 already has a USB-C port for charging, would've been neat if they just added an internal USB-to-serial chip.

That same cable works for lots of different radios, so it's not too annoying. You can make one yourself: https://www.miklor.com/COM/UV_Technical.php#progcable

Could you share any ideas on what to do with this radio (receiving or transmitting) given its hackability?

It reminds me of having a RaspberryPi or a ESP32/Arduino with nothing to code for?

The manufacturer didn't open up the firmware for THIS radio either. They made the radio reflashable so that they could release new binary blobs as requirements changed. Then people reverse engineered the firmware that came with the radio, and began writing new stuff. It's more like Rockbox than an actual open radio.

See how high the sampling rate can go over USB.

These are listed $24 (Canadian) on aliexpress, with free shipping. How is that possible? I just can't get my head around how these can be so inexpensive. Wouldn't the materials cost more? Like really, can someone help explain the economics of how this works?

Electronics are actually really cheap.

There are basically two main chips in there, one handles most of the RF chain, the other drives the display and handles button pushes. Both likely cost under a dollar each at volume. The vast majority of the other components are tiny passives that cost less than a cent each and are just for filtering and impedance matching.

In terms of development costs, there is definitely skill in component selection and packaging, but generally speaking the main PCB could have been designed by a lot of EE grads.

If you spend some time looking at it, in terms of sophistication it's barely a couple steps above a happy meal toy, but since nobody wants to make quality flexible use radios, this is what everyone ends up buying to experiment with.

Is Chinese software required? It might be just a booster rocket for Chinese spyware.

According to the article, the radio can be reflashed using a browser, but if any suspicious software was needed for reflashing, it could anyway be run in a VM after setting the USB/serial port as pass through. To program frequencies and modes then one can use Chirp, which is Open source. https://chirpmyradio.com/projects/chirp/wiki/Home

You have been conditioned by US corporations. Apple consumer electronic prices, TI microcontroller prices, Qualcomm/TI radio chip prices, Intel FPGA prices etc.

don't know what you're getting downvoted it is true

In China, the retail price is 90 yuan, which is 12.5 dollars and 17.2 Canadian dollars according to current exchange rate. Sometimes people can get them cheaper.

Radio hardware is not that expensive actually. The tech behind it is very basic and has existed for more than a century now. Hells, you can build an AM radio with just a bunch of cable and an amplifier [1]. Of course, these new radios are a bit more complicated than that, but basic SoCs are also very inexpensive nowadays, and when you get to economies of scale, things get even cheaper. It was not a long time ago, low power radios were even children's toys

[1]: https://www.wikihow.com/Create-a-Simple-AM-Radio

Long before people were modding these I got one for $20 CAD from Aliexpress. The speaker only works intermittently, requiring me to push on the case to get it to work (I guess there's a weak solder joint or something). I contacted the seller and of course just got infinite runaround. Either way, "buyer beware", these things are insanely cheap for a reason. Basically a dollar-store HT. :P

Just buy it on Amazon for $10 more, and you're good to go.

All that adds is fast shipping because someone with an alphabet soup brand name upfronted a bit of money to get a container load of them shipped from China to an Amazon warehouse.

It adds no-hassle returns.

Uh, on Amazon Canada, the Quansheng UV-K5 is being sold for $125.99 heh

Order straight from Aliexpress. You can get one for around ~$30 CAD all in depending on the day. And believe it or not the shipping only takes a couple weeks.

That's exactly what I did! Thus my original post lol.. I was refuting the parent post's suggestion to "just buy it on Amazon" as if the Amazon return policy is worth paying $100 extra for a $20 radio haha

It depends on that random reseller's pricing, no? I got mine for $30.

What the community manages to do is amazing... but I still wonder why all these hackable devices use such low power chips.

So many things on the market are basically just computers with specialized IO, but most of the firmware and MCUs don't reach the full potential of the rest of the hardware.

A few extra dollars could add literally hundreds of features if they wanted.

The website and manual mention "10 groups of scrambled voice encryption". They don't specify what this is actually doing.

I've always wondered what it would take to make a really good encrypted coms system using one of these. However my understanding is that encrypted transmission on HAM is illegal.

Using encryption on ham bands is illegal yes. You can use it on commercial bands if you buy a license from the FCC and ISM (common 2.4ghz/5Ghz) is mostly fair game as well. The practical reality is people are probably getting away with abusing it because the FCC is not omniscient and has limited resources. For an individual to draw the ire of the FCC they need to make a nuisance of themselves. Occasionally you hear of people getting arrested for using illegal cell jammers and the like. I can't recall hearing of someone getting caught using encryption.

For something like this to really get a crackdown you would need a watershed event like RC aircraft had with cheap drones. The point where very capable hardware became extremely cheap and accessible to people who know nothing about the hobby. The RC aircraft community effectively self policed for decades because the bar for entry was high enough that anyone getting involved had to engage with the community. Drones changed that. And the FAA had to step in and regulate. I think we are getting close with cheap Chinese radios. But even Baofengs still require programming and educating yourself. Devices like the flipper zero are far more damaging. Even though they are limited in their capabilities, they make it trivial for the user to make a nuisance of themselves in ways that are hard to ignore. Its probably a matter of time until a cheap radio hits Amazon that does everything for you and permits non hobbyists to ruin everything. Imagine something as capable as a HackRF but as easy to use as an iPhone. Then we have problems.

Assuming there was aggressive enforcement against it, could someone “get away” with encrypted transmission sent in low-power alongside high-power unencrypted transmissions?

Like would a well-encrypted stream look indistinguishable to a bit of noise from a low-quality transceiver?

That depends entirely on what they are listening with. One sub set of ham radio is called fox hunting which is a gameified form of radio direction finding. Some guys are really good at it. If you annoy one of them and they are persistent they can potentially track you down. The Feds of course have very sophisticated tools far and above what's available to you but if you've drawn that kind of attention you are already in deep trouble and looking at jail time. Powerful software defined radios like the RTL-SDR are inexpensive and with a PC can be used to scan broad swathes of spectrum and even decode and store transmissions. People can setup their own DIY listening posts this way. For someone with the right setup and looking at the right time they would notice you are using an encrypted transmission. To figure out where you are would involve repeated detections from multiple points. An adjacent topic is pirate radio stations. The Youtube channel Ringway Manchester has a series of videos about historical UK pirate stations and their stories. You might find it interesting.

I think you maybe answered a different question than what I intended to ask. I meant to ask - if I only transmit encrypted communications while I’m legitimately transmitting legal content … how would anyone differentiate illegal high-entropy encryption from legal high-entropy noise?

Obviously anyone can track my transmissions with “fox-hunting”. But my transmissions would superficially be valid and legal. How would they notice the well-encrypted communications which theoretically should look like random noise?

To put this in different words, you're basically asking about steganography applied to a radio transmission. I think the answer is: unlikely to be noticed unless you were receiving particular attention for some reason. Though your noise might inadvertently violate bandwidth constraints.

If you search for radio steganography or acoustic steganography you'll find a bunch of papers on the topic.

If it is above the S/N ratio, it won’t look like noise. If it is below, it’s hard to make useful.

Ah, so if you are using encryption on a digital mode like DMR or P25 for example, they have very distinct sound and appearance over the air. Its pretty unmistakable as common digital modes can be identified by ear by experienced Hams. So if I am listening on my SDR and pickup a digital transmission on a ham band I can try to identify and decode it. If I am confident I've correctly identified the mode being used and I can't decode it then its probably encrypted. Some modes like DMR even carry some information unencrypted when the transmission is. So its still possible for someone without the key to correctly identify the transmission even if they can't hear what's been said.

Trying to hide a transmission as background noise would be very difficult. I wouldn't say impossible but it wouldn't be easy. The modern technique is low probability of intercept, LPI. Which uses a combination of techniques including very rapid and complex frequency hopping as well as well as beam forming and making the transmission as efficient as possible to limit the required power. The lower power, and more more directional your transmission, the less likely someone unwanted will be able to pick it up unless they are between you and the intended recipient.

I think there's one more intrinsic safeguard for these radios vs. drones.

Handheld radios are mostly not useful in an urban setting (compared with a cell phone), and only other radio users can even be bothered by them.

Unlike "drone spotted in posh neighborhood looking into windows" as a headline, "Baofeng user briefly interferes with garage door opener" just doesn't have any edge.

That's a fair point but I've seen for a few years now Baofeng Ham radios resold as walkie talkies for recreational use. Often advertised as for powersports like ATVs and boating. This is completely illegal but these resellers have been doing it for awhile now without any consequences. Still, the real world impact is limited and mostly contained to annoying Hams. And its a meme in the community that the FCC doesn't care about Hams.

I think the flipper zero/hack rf side of things is the bigger problem. Its very useful to whitehats but they also lower the bar for a lot of disruptive attacks. Get a flipper zero and war drive any neighborhood built in the 80's and its prime hunting ground for forcing garage doors. I'm surprised we haven't heard more of that actually.

> I'm surprised we haven't heard more of that actually.

It’s a bit of an information hazard. E.g. what if someone made sewer pumps run backwards. Meanwhile the level of exploit capabilities is on the level of Spectre. There is such a wide gulf between what is and what should be that we can’t properly discuss it.

Question from a non-ham: how does the fcc define encryption?

Is it ok to speak in code, like a numbers station?

What about speaking in Navajo, like the Americans did in ww2?

What if it was a made-up tonal language with lots of clicks that sounded similar to a modem transmitting a bitstream?

"messages encoded for the purpose of obscuring their meaning"

https://www.ecfr.gov/current/title-47/part-97#p-97.113(a)(4)

It's intentionally broad, and gives exceptions for controlling satellites as the only real exception.

People try to fight that publishing encryption keys would mean that you are within the intent of the law, I struggled decades ago trying to create a digital voice mode while every OM told me I was trying to encrypt things. sigh.

Awesome, thanks

What threeio said is right. Technically, encoding data digitally isn't encryption and is fine, and there are digital modes used by Hams. But if you were to come up with your own scheme I could see some sweaty old timers try to accuse you of encryption just because their $3k Yaesu can't decode it. There's a good reason why a lot of recent innovation in the hacker and maker spaces has been in unlicensed bands. The rules for the Ham bands were written decades ago when just trying to talk to people around the world was considered experimental. Now its trivial to do that with HF with the right equipment and a bit of reading. The FCC tends to neglect the ham space which is both a good and bad thing. Lack of attention means people are probably getting away with doing a lot of harmless things they technically shouldn't be. But it also means we are stuck with rules from the 1930's.

Define ‘trivial’.

It is not trivial to set up an HF antenna that can send a signal (halfway) around the world and be used to hear a response, and it is often not repeatable without the right sun / weather conditions. It is the nature of HF, which hasn’t changed since the 1930s (and will not).

Radios have become arguably cheaper, but electrons vibrating at 3-30MHz have not changed their behavior much.

Its trivial in that anyone with minimal reading online and inexpensive equipment can do it. There's also no new science or industry development coming from doing it. HAM analog HF is mature and established.

>which hasn’t changed since the 1930s (and will not).

And that's the crux of my point. It got about as good as it was going to get nearly 100 years ago. I have a ham training/reference book from the 30's. And long range HF was a much more impressive feat back then. But if you go to youtube today basically every Ham channel has at least one video on how to do it "cheap and easy" now. One of the stated purposes for Ham from the FCC's pov was to foster innovation and development of radio technology. If that's true then it needs to evolve with the times because that is a moving target.

> Is it ok to speak in code, like a numbers station?

Good question. Probably yes but don't pin me on it.

> What about speaking in Navajo, like the Americans did in ww2?

Definitely 100% ok as long as you transmit your callsign in NATO english or send it in morse code. A language is not encryption. The ham community is super international. It's not a US English only thing.

It might cause some grumbling in your local area but it's not illegal. Especially now that repeaters are often connected to the whole world.

> Imagine something as capable as a HackRF but as easy to use as an iPhone.

This is literally just a UX overhaul away for the HackRF Portapak system. As-is the UX is slightly too awkward for the casual user, but these things trend towards becoming more user friendly over time.

Honestly a Portapak with Bluetooth module and a phone app to control it would be pretty fucking cool, now that I think about it.

https://github.com/htotoo/ESP32-Portapack

Looks like this may be in the works!

You mean like the portapack, which is based on a HackRF and allows transmission on a broad range of frequencies.. https://github.com/portapack-mayhem/mayhem-firmware

At least the normal layperson would need to understand RF to cause any damage.

This project's trying to add 53-bit *scrambling* with an ESP32. Maybe not technically encryption, but the lines are blurry https://github.com/kamilsss655/ESPRI?tab=readme-ov-file

I had to look around to find a datasheet[1] for the BK4819 which is the heart of this rig, but it appears that there are I/Q outputs on receive, and possibly I/Q inputs on transmit internally, so it's an SDR, and not limited to FM only. The low output power will likely restrict it to line of site, but it's an interesting substrate on which to work.

[1] https://touchardinforeseau.servehttp.com/f4kmn/f4kmn/FRANCAI...

Isn't UHF/VHF (edit: pretty much) always line-of-sight?

Edit: Can the downvotes please explain where I'm wrong? It's a genuine question!

Tropospheric ducting is a thing... [1]

[1] https://en.wikipedia.org/wiki/Tropospheric_propagation

Sure, but is that a thing you'd be able to (and want to) do using a small handheld radio?

It's not like HF where ionospheric reflections are pretty much the biggest appeal of the band.

Plenty of use-cases, unsure what you're arguing against.

https://www.youtube.com/watch?v=PmNo1TX1E3Q

https://www.youtube.com/watch?v=Hn7_CZurV7Y

https://www.reddit.com/r/amateurradio/comments/jcvv5g/did_so...

Who's arguing?

I was under the impression UHF/VHF is mostly used for line-of-sight communications, unlike HF, and NLOS usually needs much stronger transmitters than would be practicable in a handheld radio.

Curious to learn about other applications.

> […] and NLOS usually needs much stronger transmitters than would be practicable in a handheld radio.

While not typically thought of as a "handheld radio", Elecraft's KX-line are pretty compact and portable:

* https://elecraft.com/collections/kx-line/products/kx2-ssb-cw...

* https://elecraft.com/collections/kx-line/products/kx3-all-mo...

The KX3 can run on eight AA batteries.

There are people who use SSB on VHF to talk over long distances. There is always some bending and they can get weak signal. On rare times, troposphere ducting means they can reach hundreds of miles.

This wouldn't be useful for that since, like most handhelds, it doesn't have SSB, just FM.

Radio line of sight also includes repeaters on a mountain 100mi away (radio line of sight is somewhat further than optical) and satellites 250 miles above.

Tropo does occasionally get intentionally used by HT users though most weak signal operation is on SSB (and not on HT's, which don't do SSB for frequency stability reasons that no longer apply and amplifier linearity issues that only somewhat apply).

That I was aware of, and I'm not saying that LOS can't achieve impressive things. Quite the contrary, I think it's amazing that it's possible to sometimes reach the ISS with a small and affordable Baofeng handheld!

I just wasn't aware which applications could benefit from a (much) larger transmission power in a handheld UHF/VHF radio.

It's only I/Q on the receive side. The TX side is FM only.

I really wish someone would use one of these chips to make computer-controlled SDR radio. Basically, USB-C port on one side and antenna connector on the other.

There are lots of interesting things that could do on VHF/UHF bands with computer radio. Good example is APRS repeater. Or packet data. Receive can be done with SDR but transmit requires a radio that use audio that is flaky. I would love full I/Q but FM data would be fine.

Yeah, maybe couple of USB-C ports, one for control another for power, would make sense for using a smartphone as the controller.

This is my holy grail. All band all mode would be ideal. The Xiegu X6100 is a pretty decent close strike, and the Q900 looks solid as well, but I know I'm paying for more than just the components I would want which is a clean amp and tuner+maybe an antenna matcher in a box, just like you said, USB-C + power + transceiver + antenna out. Would be a game changer for POTA/SOTA as well as just sitting on the desk, even something small like 5 or 10 watts. I use a (tr)uSDX for my POTA/SOTA stuff on CW and SSB, and it's dinky but it definitely gets the job done -- surely something more PC-reliant wouldn't be too hard.

Looks like someone is working on this for the UV-K5: https://github.com/nicsure/QuanshengDock

There is some work involved but looks pretty fun.

The product page linked at the top of the article boasts about voice encryption as a feature, but that's still very much illegal on ham radio bands in the US, right? Or is it just referring to CTCSS/DCS?

They do mean scrambling, and yes that's illegal on ham bands. CTCSS/DCS isn't encryption/scrambing, just in band signalling. You can listen to CTCSS/DCS with any radio even if they don't support it.

Looking forward that someone will port FT8 to this devices. At the moment you need a phone or a PC to tx/rx in FT8.

this is what im looking forward to, too. ive even started making some hardware around digital modes so this might make a cheaper frontend + filter investment lol

Does it have the hardware? Per the article the CPU and available flash memory are super limited.

FT8 would be pointless. FT8 uses SSB which this can't do. Doing FT8 on FM is a waste of bandwidth and low-signal. FT8 is usually done on HF since that has long-distance propagation and it is important to pick out tiny signals. People do FT8 on VHF but they use radios with SSB.

The radio probably doesn't have the processing power for FT8. A Raspberry Pi 3 was struggling for me. Also, a big part of FT8 is choosing what to send and who to respond to, need a good display for that.

It seems that there is a firmware doing SSB (I don't understand if it's real SSB or something emulated). Anyway, the radio chip of UV-K5 is able to manage distinct I-Q signal, so it just a matter of implementing SSB via software.

SSB requires more sophisticated frontend than FM because the channel is smaller and reuqires less noise. There are HF radios that use a simple signal generator, but then need a complicated frontend to be able to received anything. The cheap SDR HF radios are $500 when SDR VHF handhelds are cheap like this one.

One thing that I picked up on the spec sheet there which you shouldn't really have in a ham radio is a scrambler. I don't know if they really mean something like DTS/CTCSS which isn't actually encryption, but the word encryption shows up in the user manual, though this might just be a troubled translation.

I'm curious if anyone who has one of these has any further clarity on what exactly that feature is.

It's "voice inversion" [1] which conceptually is just flipping the baseband signal's spectrum around a mutually-agreed upon frequency, which serves as the key. The resulting audio is difficult to understand. The UV-K5 is only capable of selecting a single key frequency; more clever schemes will have some sort of rolling code/hopping.

This is separate from CTCSS/DCS which this radio also supports, and is not a method for obscuring meaning.

You are correct that it is illegal to use on ham frequencies (which can't obscure meaning), but I wanna say it's legal to use on FRS. Of course, this radio is not type-certified for FRS, so technically that would also be illegal (although many people don't care so much about type-certification for FRS). You are correct, it has no completely legal use on this particular radio.

[1]: https://en.wikipedia.org/wiki/Voice_inversion

It could be a mistranslation and just refer to DTS/CTCSS. The cpu isn't powerful enough to implement real AES encryption and the datasheet doesn't mention a hardware crypto module. It could be an inversion scrambler, that's not difficult to implement in software and even if it doesn't have that stock someone could implement it. But scramblers have limited utility now. They are really only useful to annoy others, they are trivial to defeat. Undocumented encryption capabilities are also not unheard of with Chinese made ham radios either. Seems the FCC really only cares when people make a menace of themselves and draw their attention.

People should be able to have encryption if they want it. The rules are absolutely unenforceable either way and there isn't actually any drawback. I'm a ham but most hams like to freak out about it because they think it'll cause companies to suddenly start using ham bands with impunity. The reality is, we need to enforce the existing rules about IDing in the clear periodically and then send whatever you want after that. You already can't decode most of the common digital modes without significant effort because they rely on proprietary vocoders so it's not like encryption would change anything.

Cue hams being angry:

To be fair there are a large number of people that think the AMBE vocoders should be removed from the ham bands too. Personally I don't think they run afoul of the rules since the intent is not to obscure meaning.

I think encryption is a terrible idea for amateur radio not because of companies doing things (they have ample land mobile allocations), but because it would be filled with cryptoshit scams in no time at all. I know of at least one RF-based cryptocurrency already. I'd also be worried about high speed traders on the HF bands since they're already trying to get licenses in the shortwave broadcast bands as it is. Not to mention I've yet to hear of a legit use case for encryption in the amateur bands that isn't served just as well by other licensed (and licensed-by-rule) services.

My belief is that the core purpose of ham radio is experimentation, so playing with modern protocols, modulation schemes and techniques is really important for it to remain relevant in the future. It can't forever exist as an HF/VHF AM/FM service forever. The future is AES/RSA, DSSS/CSS, internet access, and mobile mesh systems.

All that said, if we went to allowing it with a cleartext ID, how do you think the crypto scams would defeat that in a scalable way?

People can use encryption all they want. They just have to do it in some part of the spectrum that wasn't explicitly set aside for more "open" kinds of communication. Use the ISM bands, or get a license for commercial spectrum. It's really not a big restriction.

https://youtu.be/1dt6ykstvOo?si=itGvWonj4MPQaSrq&t=384

Mentions that it's a basic scrambler. I doubt a $30 radio has a chip powerful enough for real-time (proper) encryption.

Too bad this is not a DMR radio.

Some other custom firmwares have been made for other radios, like the GD77: https://www.opengd77.com/ and the MD380 and similar: https://md380.org/

But as far as I know they are still just mods on the original firmware. And DMR is kinda a must-have now for hams. Analog activity is negligible now on the VHF/UHF bands, at least where I am.

The "best" Chinese DMR radio seems to be the D878UVII but it's extremely expensive ($200 or more).

By the way the Retevis RA79 seems to be the same radio. It's cheaper here on Amazon so I think I'll try that. Also, "Retevis" means "Ass fish" in my language so that's definitely a plus for me!

This looks interesting. A common complaint about the Baofengs is that they transmit significant unwanted harmonics outside the intended frequency. Do these radios have this issue as well?

I'm very excited about the prospect of more radios that can be easily programmed with mainstream languages such as Python / Rust / C++. Hopefully this becomes a stronger trend going forward.

I was about to buy one of these (of course), when I noticed that the K6 exists. Which one is the best one to buy to hack around with?

The K6 has a USB-C port for charging. Of course, they bungled it and it doesn't have the CC resistors to trigger PD chargers, so you need an A-to-C cable, or some soldering skillz. Other than that, they are reported to be identical hardware.

My K5 also has a usb-c port for charging. AFAIK they are identical except for slightly different housing.

Are you sure about that?

I just ordered the UV-K5 from Amazon sold by Quansheng and it is labeled as having USB C charging.

There's also a third party seller with an item description of "UV-K6 UV-K5(8)". That listing seems fishy.

I don't see a "UV-K6" listed on the Quansheng web site [1].

EDIT: After more research it looks like the UV-K5(8) is also known as the UV-K6 [2]. I'm curious which model I receive.

[1]: http://en.qsfj.com/products/?series=3

[2]: https://hagensieker.com/2024/03/12/quansheng-uv-k6-radio-rev...

UV-K5(8) is legit: http://en.qsfj.com/products/3268

Yes it has a usb-c port on it which you can charge with a type-a to type-c cable.

The problem is that it violates the spec by omitting the resistor and you can't charge it with a c to c cable. That's where the frustration comes from.

Soldering skillz are always nice to have but the amount of Chinese 'USB C' gear that skimp on the 5.1K resistors is truly enormous, and adding them gets old really fast. Some designers even combine cc1 and cc2 to save 0.01¢ on the second resistor, with predictable results..

They probably don't know they need them. A lot of stuff is just copy-pasted from old reference designs that used micro usb and then they slapped a USB-C connector on for marketing purposes.

If you've been an electronics engineer long enough to be able to design this radio, you almost certainly know the resistors are needed, or can discover it with a single Google search ("PCB design micro USB to C upgrade").

A more likely story is cost savings. It's cheaper not to support it, from an assembly and testing point of view.

A review from Amazon on UV-K5: "Warning though, the USB-C port feature is misleading in some way: you can't get it charged with whatever USB-C cable you have, it needs to be a USB-C power-only cable with USB on the other end (like the one provided). If you try USB-C to USB-C from your Mac it won't work. Also, USB-C direct charging can only charge it to max 80%. Other than that, this is quite a nice radio well built."

Sigh, won't buy any electronics that can't just charge USB-C without bs..

https://www.amazon.com/QUANSHENG-UV-K5-Rechargeable-Emergenc...

"won't buy any electronics that can't just charge USB-C without bs.."

I don't think that leaves too any ham radio to buy then?

Is there a legit way to use these without a Ham license? I sometimes ski in areas with bad cell service and it would be neat to have an alternative. I've seen portable CB radios but they're on the pricier side

You can always listen. It's transmitting that requires a license. Possibly also the modding as well.

It's probably pretty easy for anyone here to get Technician, and probably General. I'd expect a large number could get Extra, and probably in one sitting.

So you're right, you could use ham radio, but it does require a license, but it's probably not hard to get.

Also, if you've an emergency, technically whatever you need to do to get help is fine. But it had better be a life and death emergency. Especially if you end up taking over the radio to a government agency, e.g. FAA or DoD.

> It's probably pretty easy for anyone here to get Technician, and probably General.

Yep. If you're reading this, you probably have the technical background to pass the Technician exam pretty easily.

A big chunk of the exam is stuff you learned in the physics class you probably had to take along the way. The rest is largely about specific regulations, like the power limit at this frequency is X, and don't build a tower more than Y tall within Z of airport.

If you can remember "frequency * wavelength = speed of light" and "watts = volts * amps", you could probably get a passing score on the technical part of it without studying in advance.

Most of the rest of the Technician exam is what is the absolute minimum you need to know about Part 97 to avoid disrupting your neighbors' radio reception and/or keep the FCC from knocking on your door.

Exactly. They're the training wheels: if you never do these things, you'll be fine. (And if you do the right things and your neighbor still gets annoyed, we won't get mad at you.)

General and Extra are more like "OK, here's how you can get as close as possible to those things we told you not do to without getting in trouble."

Short answer: no Nuanced short answer: operate on frs channels or buy a gmrs license and operate on those bands. This is still illegal because your equipment isn't allowed to operate on these bands but not heavily enforced. Use at your own risk.

IIRC, the transmit power of all versions of the UV-5R are too high for FRS.

Besides being noncompliant in ways that people are more likely to consider harmless technicalities, such as the antenna being removable.

There are 5W and even 50W GMRS bands. You would need a license in that case, but it's not expensive. The handheld would be non-compliant, but that wouldn't be detectable on-air unless the deviation or power is outside spec for that frequency.

https://en.wikipedia.org/wiki/General_Mobile_Radio_Service#F...

I wonder if this could be programmed to operate on CB bands only? If it could, would that be legal to use on the air?

I don’t think it would. IIRC, CB radios are type-certified, which means that the transmitter itself is licensed, rather than the operator (similar to FRS).

That said, these days the FCC gives absolutely zero shits about what happens on 11m, so I wouldn’t expect any knocks at the door if you modify a non-CB radio for use on CB channels.

In addition to it being technically illegal, you probably can't transmit well on CB without an external antenna and amplifier.

Wrong frequency range - these handhelds are designed for 2m and 70cm, and CB is 11m. You'd have to do a lot of tricky hardware modification first, and then hook it up to a rather large antenna for a handheld.

You can, but the problem is that the radio chip is not designed for the 27Mhz, then you will generate an huge amount of spurious that will pollute other bands and wasting lot of power. I advise don't do that, just to avoid to interfere with some critical services.

The better question might be: What is your imagined use case for this radio? A VHF/UHF handheld is more or less limited to LOS transmission, so you would either need to be within reliable range of a repeater or another person with an HT tuned to that frequency. If you’re looking for something you can use in a backcountry emergency, you’d frankly be better off just plunking down the money for a satphone, which is going to be much more reliable. An HT radio is unlikely to be of much use in that scenario, unless you know there’s a repeater nearby that is regularly used and that you can hit from your location. OTOH, if you’re looking for a new hobby and a gadget to play around with, get a license, pick up an UV-K5, and have fun!

If you want to get a license just to play on the radio, it is super easy. A Technician license will allow you legally to use any VHF/UHF radio with full access to those bands (plus all of 6m and some access to other HF bands).

It’s extremely simple to get licensed. Put the HamStudy app on your phone, run through the question pool/practice exams until the info is in your memory, and then sign up for a remote exam on HamStudy.org. I studied for my Technician license for like a day and a half and aced the Tech exam. I aced my General and Extra exams within a week using the same method. I have no background in tech or EE. So, yeah, it’s easy.

I agree in general, that if someone has a short amount of time, a small amount of money, and any kind of ability to memorize some rules, then getting a Tech license is a breeze! And if you're actually enjoying it, getting a General is not difficult, either.

In my humble opinion, the rules on antenna and transmit power for FRS are annoying - garbage range and prone to interference. I wouldn't want to risk pissing off the FCC or a ham with too much time on their hands by running hot on FRS constantly...

But for occasional backwoods travel with friends or to use in an emergency without clogging up ham frequencies, it's totally possible to reprogram certain Baofengs and these radios to transmit on FRS frequencies with low wattage. In fact, I think FRS was modified to allow higher power now, so the low-end of these radios fits. It's just the antenna reg that they break now.

Yeah, definitely agree 100%. It’s not a popular ham opinion, but the general follow-up to “Is this illegal?” should be “Will anyone care?” Lots of practices in the radio world are, strictly speaking, illegal, but no one cares. See all the guys running multiple kW amps on CB, which is limited (laughably) to 4W AM and 12W PEP on SSB.

If you modify a bunch of Fengs to run on FRS/GMRS freqs to talk up and down the mountain out in the middle of nowhere, sure, it’s illegal, but if no one hears your transmissions other that the people on the mountain, it’s not an issue unless you take the FCC regs as moral edicts. But if you’re looking for a way to get a signal out in an emergency, a satphone is still going to be your best bet.

Less for emergency use (in a life or death situation I'm less worried about upsetting the FCC), more for "hey dude, wanna meet up for lunch" or "FYI I'm heading back to the car".

Ideally something that doesn't require everyone to have a license (eg I can just hand a friend a without advance prep) but with a couple miles of range without LOS (maybe I'm underestimating the Toys R Us walkie talkies but I'm assuming they don't reach that far).

I've also seen LoRa based solutions like Meshtastic but not sure how practical it is

Yeah in that case, you’d probably be better off just picking up some decent GMRS handhelds. Spend a little more on some antenna upgrades, and you should have no issues. If you really want to stay on the right side of the law, you can have everyone in your group (who isn’t related to you) throw $35 at the FCC for some GMRS licenses. But, depending on terrain, you should be able to stay in reasonable contact with everyone with 5W if you’re within a mile or two.

I'm pretty sure you can find the same radio hardware platform but FCC certified for GMRS (or so the label says anyway). Maybe they added filtering to get it to pass? That means a $35 GMRS radio with USB-C charging, swappable antennas, and higher transmit power.

He's already seen Meshtastic, which is something I definitely want to play with for his exact use-case: coordinating with friends while skiing.

The BC Link is a commonly used GMRS radio for backcountry enthusiasts.

https://backcountryaccess.com/en-us/c/bc-link-radios/

Any decently made GMRS radio should be fine for coordinating around the ski resort. I've had mixed results with FRS as the range is quite poor. This is amplified by the fact that the other party could be on a different face of the mountain as well as covered by trees. It's also convenient that many GMRS and FRS frequencies overlap, so if someone in your party only has an FRS radio or doesn't have a license, they can still communicate with GMRS users, assuming they're within range.

As another commenter pointed out a satellite communicator would be preferable in an emergency situation, as FRS/GMRS cannot be relied on to request emergency or rescue services. I keep a Garmin inReach Mini for this purpose.

https://www.garmin.com/en-US/p/765374

> legit

If you have an emergency you can initiate emergency traffic.

Bought an UV-R5 years ago during a short prepping spree as backup if the mobile net is compromised. Took off the antenna and transmitted less than a second to see if an RTL-SDR would pick up the carrier wave. Then it went into storage and I top up the battery once per year.

Running a transmitter without an antenna is a great way to ruin it.

I thought of that but if it can’t handle that for a second then I can’t rely on it for prepping purposes.

But to clarify, for the purposes of amateur radio, "emergency traffic" is defined as:

> essential communication needs in connection with the immediate safety of human life and immediate protection of property when normal communication systems are not available

(47 CFR § 97.403)

That is, just because your communications are related to an ongoing emergency doesn't automatically give you the right to transmit without a license.

You can use any means necessary if life or property are in imminent danger and only if you're already licensed. The section of Part 97 everyone quotes applies to amateur stations only (like the rest of Part 97).

So unless there's another part of the FCC rules that allows this I'm unaware of, even emergency communications made by unlicensed users are illegal.

If life is on the line, worrying about the FCC is pretty low on the priority list.

In my country if I had the means to avoid an emergency but did not utilize it I can be held liable.

What's the reasoning for not getting the license? It's super straightforward, the test questions are about some RF basics and the regulations you'd have to comply with anyway, and it's super cheap and lasts a lifetime.

IOW, I think you're solving the wrong problem.

> lasts a lifetime

You need to renew the license every 10 years, but as long as you renew you don't need to take a test (which is maybe what you mean by "lasts a lifetime").

Yeah depends on the country/jurisdiction - in Canada, an amateur radio certification is valid for life, and doesn't require any sort of re-testing or paid renewal or anything. Pretty nice. One of the few times the government has really done something right, IMO :)

In the US, it lasts a lifetime but you have to tell them you're still alive every ten years. This is free, but if you don't file the form, your license is no longer valid.

In a lot of places your name/address is publicly linked to your callsign when you have a HAM licence, in databases anyone can search.

Which is absolute shit.

If you're in the US, you can use any address you can receive mail at (work, a PO box, mail forwarding service, etc). I used a cheap mail forwarding service (it actually doesn't charge a monthly fee, just shipping and I never get mail there anyway). The important thing is to get this setup before you even get your FRN because the change history of your license is also public, so once your address is there, it's viewable forever.

You can snag one and listen, just can't transmit. Otherwise, no, no way to legally use it without obtaining an amateur radio certification/license.

Getting radios for skiing as a family and group has been a game changer. Rocky Talkies are very accessible.

You got your kids to pass a ham license test? Kudos.

Rocky Talkies are FRS.

They have a GMRS version now too.

For that, I'd just get FRS (US) or PMR446 (EU) radios (or your local equivalent). No license needed and very cheaply available but still interoperable across manufacturers.

I could be wrong, but I believe that anyone, even without a license, can use them to listen to ham bands at anytime. You can not use them to transmit, unless there is some sort of emergency.

I believe both the FCC and ISED have exceptions for unlicensed individuals to use any amateur frequency in the event of a genuine emergency. For the price it could be worthwhile to program one of these with local comms frequencies. As long as you don't transmit outside of an emergency it's perfectly legal to both have and listen with. Plus it has a flashlight!

> Like Baofeng’s 5R, Quansheng’s K5 as a radio transceiver is fine.

In other words, its output is so dirty the FCC would ban it if they were paying attention?

"for over a decade, Baofeng has been the name in Chinese handhelds."

well, its certainly A name...as an amateur extra and a VEC, i tried...i really tried to love these radios.

- my first baofeng couldnt hit the repeater across the street from me.

- my second baofeng arrived with a flashlight i couldnt turn off, and died an hour later.

- my final baofeng (a gift) died during a contest and couldnt even hit a reference repeater. thankfully i was only really using it for a flashlight in a camping tent.

...but i cant. these things are hot garbage for preppers and gun nuts.

ive an bf-f8hp that outperforms kenwood ht everytime i compare, with stock antenna and all. shrug

Apparently the newer ones are significantly improved. https://forums.radioreference.com/threads/baofeng-spectral-p...

FWIW the Baofeng radio I tested, a BF-F8HP circa 2017, was (barely) compliant with Part 97 spurious emission requirements.

Your assertions are applicable to early UV-5R models. However, some have demonstrated that more modern iterations have made substantial improvements.

https://forums.radioreference.com/threads/baofeng-spectral-p...

That is good news.

This may not fit here but I’m going to ask if anyone knows; has anyone been using starlink phased array antenna s for point to point microwave communication? What would be fruitful search words for google to find out more? Thanks!

I don't have any personal knowledge, but you might want to ask Oleg Kutkov - he has been reverse-engineering and repairing Starlink antennas for some time.

https://olegkutkov.me/ https://twitter.com/olegkutkov

Not answering your question directly, but curious why you want to take on the significant endeavour to hack up something like this, when you can just buy e.g. a pair of Ubiquiti airFiber 5 and get 1 Gbps with >100km range?

It's not terribly useful yet but I like where we're headed. Needs a beefier CPU and more memory. I'm going to buy a few more to help signal to manufacturers that this is the right direction.

> Needs a beefier CPU and more memory

The MCU is $0.21 at quantity on Alibaba. Make it a whole $0.50 and they'd really have something. Kind of a shame.

I was surprised to see that it only costs around $14 in China, so I instantly ordered one. It would nicely fill the gap in VHF bands that are not supported by my Tecsun PL-365.

Just checking: using a modded handset on ham frequencies with a ham license would still be perfectly legal, as long as you still abide by power/no-encoding rules right?

Provided you are broadcasting within bands you have license for, under the power limits for that band/license, and it's not encrypted... yea, you're good.

Historically the FCC hasn't care about modding radios, until people start doing illegal shit with them... like broadcasting FM on AM Airband freq's

My understanding is that the purpose of amateur licensing is to facilitate and encourage experimentation and learning, up to and including people building their own hardware; that's why the rules are about how your machine affects the world.

That's exactly right. I'm licensed by the FCC to build my own radio from a bucket of spare parts if I want to, and I can do whatever I want with it as long as I stay inside their rules. The RF I generate is what I'm responsible for. How I get there is up to me.

Someone told me once that Beofang uses the open source DSD (digital speech decoder) package in their scanners/radios. Can anyone confirm this?

How do they make it work on frequencies beyond its range? The diagram puts its range below the aviation band.

I wonder if DMR, D-Star, or Fusion can get added to this

Almost certainly not. The usual challenges here are:

1. The codec is computationally expensive (at least by embedded-device standards). Often this is handled by a dedicated ASIC.

2. The waveform needed for DMR (TDMA 4-FSK) or D-STAR (narrowband GMSK) isn't something this radio's hardware is built to generate.

The RF chip in the UV-K5 is a BK4819, which does have some limited F2D+F1W FSK data capability. Anecdotally it sounds like it's limited to 2-FSK though. You might be able to get APRS text messaging / AX.25 packet radio working.

I'm still waiting for somebody to build a truly hackable SDR-based HT that can be programmed with custom waveforms.

APRS is doable with custom firmware.

I use this custom version of the egzumer firmware https://github.com/kamilsss655/uv-k5-firmware-custom but I don't believe it makes any changes to APRS functionality compared to the repo it's forked from. I believe I also came across a repo with a dedicated APRS firmware being worked on but can't find it at this time.

Sounds excellent! I suppose I'll buy one.

For USD28? Oh yeah. :)

Pretty cool but is the TX / LPF still shitty? The cheaper radios usually are a real miss on this front.

It's kinda sad that the state of art moved to China, Bao what? Give me a Kenwood or something

Have you seen the price of the new kenwood th-75?

I just sold my th-d74 to a chap in Moldova of all places and that was a really fun handy for all the extra toys on it but I will NOT be getting the 75!

~$750 for anyone else who was wondering.

Is it hackable?

I don’t think so.

By default the feature set is pretty comprehensive though: RX coverage from 100khz through 512mhz with native ssb, cw filter, am and of course nfm & wfm. GPS plus various features on top of that like track logging. Dstar. A packet TNC built in. It exposed IF over usb for use with an SDR. I used it for satellite work a lot of the time (since tx was limited to vhf & uhf), it didn’t have full duplex like the 2 generations prior kenwood which I forget the model number of.

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