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Comment by Syonyk | Hacker News Reader

This appears to be "video streaming" style transmitters, not an ADS-B out sort of location transmitter or anything.

And it seems that HobbyKing just... hoped nothing would happen.

> As spelled out in ARRL’s 2017 complaint, the ARRL Laboratory had documented that the operating frequencies of these drone TV transmitters near the 1.3 GHz amateur band were dip-switch selectable for frequencies internationally assigned for use by Aeronautical Navigation, GPS, GLONASS L1, ATC Mode “S,” as well as to both the interrogation and reply frequencies used for Air Traffic Control Air-Route Surveillance “transponder” radar systems. “Transmissions from these drone TV transmitters would have caused harmful interference to these essential Navigation and ATC Radar systems, presenting a real and dangerous threat to the safety of flight,” Carlson said.

That's impressively ballsy. I'm glad the FCC smacked them down pretty hard. It's not like global frequency allocations aren't well known.

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I suspect this bit didn't endear them to the FCC either:

HobbyKing had told the FCC that it had no notice of the Commission’s authorization requirements; that the Fifth Amendment relieved HobbyKing of its duty to respond; that the forfeiture amount was inappropriate because its parent company, Indubitably, Inc., lacked the ability to pay to the Forfeiture Order; and that the Commission was time-barred from taking action against ABC Fulfillment Services LLC because it was not part of HobbyKing’s business.

It's like I'm reading "Sovereign Citizen: Corporate Edition". Why did someone honestly think there was even the slightest chance of that response helping their situation? "We weren't importing, we were travelling!"

Ouch. Either they had a terrible lawyer or demanded the lawyer they did have make the impossible happen.

Linux allows individuals to override tx frequencies and power on many devices, but at least that’s done in software. I could understand if the dips were for setting bits on a frequency divider and could allow selecting any frequency, but having them directly correlate to reserved frequencies is beyond the pale.

>but having them directly correlate to reserved frequencies is beyond the pale.

The whole point of this cheapo hardware is that it can be used for whatever just by setting switches and therefore achieves massive economies of scale. They sell the same hardware to the drone makers and the radio makers and so on.

IIRC these switches were not user accessible. The manufacturer set them in the right position.

> IIRC these switches were not user accessible.

They were definitely user accessible in at least some of the products. Here are a couple of the devices named in the FCC complaint which obviously had exposed DIP switches:

https://hobbyking.com/en_us/aomway-700tvl-cmos-hd-camera-nts...

https://hobbyking.com/en_us/1-2ghz-mg-500mw-8ch-a-v-wireless...

https://hobbyking.com/en_us/x40-l-25mw-tx-cnc-alloy-cas.html

There were undoubtedly a number of others which could be switched between frequencies in other ways, like with a pushbutton.

I still don't feel great about this. It should be up to the end user to not break the law.

My initial thought was also that it sounded excessive, until I got to the parts about interfering with assorted Air Traffic Control frequencies, only 1 of the 7 possible selectable bands being legal for use, broadcasting (in reserved bands!) at higher power than allowed for the device type, selling 65 other noncompliant products, claiming that the constitution protected them from having to respond and refusing to agree to more than "We'll try not to do it again but no promises."

After that, throw the book at them. I'm amazed they didn't claim that the FCC had no jurisdiction because they only recognize county sheriffs as authorities.

After all, what could possibly go wrong with remote controlled flying transmitters that interfere with GPS AND ATC navigation systems?

> After all, what could possibly go wrong with remote controlled flying transmitters that interfere with GPS AND ATC navigation systems?

Do you think the people who operate or use these things are completely helpless and have no contingency plans?

The people in here saying the sky is falling are insane. People who operate disruptive devices are caught, and then educated and/or fined all the time.

Absolutely they have contingency plans and it's unlikely something with these would cause a jet crash, but in a scenario with instrument flight due to weather, taking out one of two additional positioning systems adds noticeable risk.

Low visibility. No GPS. Impaired ATC. How many additional separate systems have to be affected to be a real problem?

Looks like you're moving.

> until I got to the parts about interfering with assorted Air Traffic Control frequencies

I'm ok with this.

It is up to the end user to not break the law. But...

> In its earlier Forfeiture Order, the FCC said it had made clear that “[d]evices used in the Amateur Radio Service do not require authorization prior to being imported into the United States, but “if such equipment can operate in amateur and non-amateur frequencies, it must be certified prior to marketing and operation.” The FCC investigation found that 65 models of devices marketed by HobbyKing did not have the required FCC certification.

It's also up to the equipment manufacturer or importer to make sure the equipment they sell in the United States is certified by the FCC.

Just to add more context to this - it's easy to create a radio device that outputs RF on frequencies outside the intended range. This is one of the main reasons we have the certification requirements to begin with. It would be bad enough to do it by mistake, but these things do it by design.

GPS signals from the satellites are extremely weak, and actually are below the noise floor. GPS uses processing gain tricks in order to see the signals at all. This means that a terrestrial based transmitter doesn't have to put out a ton of power to break GPS in a large area. Like, many square miles. It makes sense to me to outlaw the sale of RF electronics that are made to transmit on that frequency.

Usually I would agree with you, but it's sort of like selling a laser pointer with a user-accessible switch that would make it a powerful directed energy weapon.

I went to a GnuRadio conference a few years ago where a lot of presentations were on directional tracking of signals. One huge issue is that truckers are using GPS jammers that plug into the cigarette lighter socket to block the truck tracking systems from knowing that they are driving outside of their legal time limits. One trucker has left his jammer plugged in for a day or two. The nearby port was entirely shutdown until authorities found the jammer because the massive ships couldn't navigate the tight quarters of the port without GPS. One project was using cameras along with multiple antennas to attempt to track who was driving past a particular overpass with a jammer turned on. A cigarette lighter socket has the potential to put out tens of watts out RF power which can almost certainly jam anyone that can't use the military anti-jam GPS channels.

>but it's sort of like selling a laser pointer with a user-accessible switch that would make it a powerful directed energy weapon.

...I see no problem with this. In fact, I'll take 5.

You're proving his point?

People will buy this with the intent of misusing it, therefore the government should stop people selling it.

Sure. Can you afford to pay damages after you inadvertently blind yourself, and everyone else in a hundred meter radius around you, with diffuse reflections off whatever you point the laser at?

That's a selfish framing, though for that poster it's probably a good choice. However the thing that they really should worry about is harming others in the first place. If I was blinded by them, money would be great to get but no amount is going to make up for the fact that I'm blind.

I'm aware. Have you not seen the occasional news articles where someone with a cell/GPS jammer gets caught and fined for it? Last one I remember was a trucker jamming his company's GPS to prevent speed tracking.

It's reasonable to expect the end user to not break the law because enforcement is possible. Even if enforcement was impossible, prior restraint of natural rights to just do stuff should not be on the table. Should we ban CNCs because you can use CNCs to build things that kill people?

I think the obvious difference is design intent.

It's just not realistic to enforce at scale.

As an example of this, look at the explosion of cheap handheld radios that can operate across all different parts of the spectrum flooding in from China, enforcement has been... more or less non-existent except in the most egregious of cases. Generally the range on these things is only a few miles, and trying to pinpoint a single intermittent transmission even if it's static within that few miles can be _extremely_ time consuming.

And we're talking about a very limited shared resource that we rely on for many aspects of day-to-day life.

Where it _is_ possible to enforce at scale is at importation/sale.

Yes, any random yahoo can get the parts to put together an illegal transmitter. But the scale of that problem is a hell of a lot different than a product being mass marketed online for $50 with no indication that it's illegal to operate.

The simple fact is if the market gets flooded with cheap devices that don't follow the spectrum allocations, large swathes of the spectrum will very quickly become useless. It's pretty a straightforward example of the tragedy of the commons.

EM spectrum is something sovereign states take Very Seriously, and if that requires hardware makers to lock their hardware in to approved frequencies so be it (from a state perspective).

If it were a product for licensed radio operators, sure it’s up to the user. But for the general public, it’s really not appropriate for them to be able to flip a switch that breaks international law, and have an elite Dutch police team haul them off for trial in The Hague. Even if that does sound awesome.

I’m not going to trust aircraft safety to one jackass who might not care about the law — or might not even be aware of the consequences of what they are messing with.

This goes beyond just breaking the law. This endangers others' lives.

I agree. Is SDR gonna be made illegal? Same idea.

I believe most of the SDR community is about receiving, which is by and large, legal.

The bits I've seen involving SDR transmission has been very clear that it's only to be done if you're a licensed operator.

Technically, you’re not allowed to “operate” on bands you’re not licensed for, including rx, but enforcement is difficult, of course.

Edit: If your device has any transmit ability, it falls under above. If your device ONLY has rx capability, it does not. Many of the USB SDR dongles DO have the capability to tx, albeit at only ~0.5 watts. This is generally not advertised in the device, but their chip does technically hav an amplifier capable of sending out signals, though usually you would also need an antenna with a shunt. I'm quite certain on this.

Again, in real life, it does not matter.

This is incorrect at least in the US. You are allowed to receive practically everything. There's only really a carve out for analog cellphone frequencies, but that's about it.

You just jogged a weird memory out of my head. In the early days of the internet there were sites that had pirate audio streams from analog cell phones. It was pretty sporadic but a very interesting sort of slice of life thing.

I used to watch analog TV streams that were being reroadcast on the ShoutCast network years and years ago.

It's a strange thing to see white-snow-static redigitized and then drop bit-rates.

> It's a strange thing to see white-snow-static redigitized and then drop bit-rates.

Old-school white snow static is theoretically the most uncompressable thing, right? So some poor encoder is being told to "send this at 384kb!" and it just throws its little robot hands up and says, "fine, here's your super blocky bullshit. I'm going on break..."

Or something like that?

Modern codecs detect noise, filter it out and add back artifical noise at the decoder (especially audio codecs can do this with all kinds of noise). I think back in the day, video compression would likely not have an issue as noise is high frequency and if you're compressing images, that's the first thing to go, you'd just get a blurrier image.

That’s under federal law. A few states add some restrictions. 5 of them disallow listening to police frequencies on portable radios without a license (but a ham license is acceptable). Florida and New York are the biggest states with this restriction.

My understanding is that operating on a frequency requires that you be transmitting on it, not whether the device is capable of transmitting on it.

For instance, you can own one of those cheap handheld Baofeng radios that is capable of transmitting on all sorts of frequencies, so long as you never transmit (and you don't listen to any forbidden frequencies)

Happy to be corrected, but all the resources I've dug up say that it doesn't matter whether the device is capable of transmitting or not.

In the us you're allowed to receive everything but the cellular phone spectrum without a license. You or the device needs to be licensed to transmit, however.

Note that this isn't the case everywhere. I believe in the uk it's illegal to listen to air traffic, but I would need to look up the specifics to give anymore detail.

Receiving of certain bands is prohibited, from memory the ones used on cordless phones and something else. All devices sold, say frequency analyzers, have to have a bandgap for them to pass FCC validation. It is common to remove these bandgaps and ignore the law because everyone seems to accept they are really dumb and they wreck the sensitivity of the instrument.

The bandstop filter requirement is mostly a stopgap measure from an analog era when cell phones were basically trunked FM radio systems. That limitation serves no purpose nowadays.

It's not cells or even maily cells, it's a weird cutout for in home wireless phones and some related tech.

None of the cheap USB SDR dongles have transmit ability.

The reason being that they are based on a cheap Receive Only chip set.

Those that do have TX are much more complex and expensive.

BTW, you've pretty much discredited your own post by talking about a "antenna with a shunt". Whatever you think that is.

Certainly untrue in the United States, though there are some bands that are prohibited to listen to — the old 800 MHz analog cell phone bands. And you won’t get 500mw transmit out of usb SDR dongles.

> I’m quite certain of this.

Hmmmmm

> shunt

LOL

TX SDR is already illegal, unless you have the appropriate license. If you don't stop the sale of cheap illegal transmission devices, there will be millions of instance of illegal transmission, most unintentional, which would make enforcement impossible and ruin the spectrum.

Even if you're a hardcore libertarian, you have to be somewhat pragmatic here. The freedom to do whatever the fuck you want is nice, but being able to board a flight without fearing that it could be endangered by any random fuckwit who doesn't know what they're doing is a bit nicer. While it's not that hard to cobble together some electronics that would have the same effect, this is about limiting it happening because some idiots flipped the wrong switch, or making it just hard enough to stop most evildoers who would do it on purpose from actually doing it.

With generic equipment like an SDR which requires one to specifically do many things to break the law.

However having a piece of unlicensed radio equipment for use with unlicensed operators which has essentially a “flip this switch to break the law” the situation is quite different.

Then people would buy phone jammers if they could easily be sold

Kits are already easy to buy. People don't bother buying the kits because if you use the jammer generally you are found. Occasionally pops up in the news.

" if you use the jammer generally you are found. Occasionally pops up in the news." - only people who are found pop up in the news. Your logic looks faulty.

The thing with phone jammers is that they actively flag "I am here" and are easy to locate.

Because phone jammers cause serious problems to the phone companies, they have teams in the field actively tracking them down. And the phone base stations run software which automatically flag that they are present and log the co-ordinates.

The FCC doesn't even need to get involved.

Easily like preassembled on amazon prime and many more would try it

No, dip switches are for end user configuration. Radio modules use firmware or other semipermanent and non-user accessible configuration to set frequency bands which is usually for regionalization. There isn’t really a use case for transmitting in global navigation bands outside of malicious jamming or spoofing.

This. They could easily have just masked out some different jumpers with zero-ohm resistors to set the frequency band. In fact, it would have been cheaper to build that way. The only reason to use DIP switches is to let people mess around with the frequency themselves.

One of the requirements of radio equipment is that it must not be easily user modifiable to operate on the wrong frequencies. In the past, that has been construed to include where a user could use a soldering iron to replace a resistor. So certainly changing some DIP switches counts too.

Possibly, although I’ve definitely got some old Hobbyking video kit where the DIP switches are totally user accessible and can definitely go into bands they aught not. Likely not the same kit (it’s about 10 years old now) but… there’s very likely still super sketchy stuff available there.

It's cheap and easy for a manufacturer to just solder the settings they want and leave the dip switch off.

> As spelled out in ARRL’s 2017 complaint, the ARRL Laboratory had documented that the operating frequencies of these drone TV transmitters near the 1.3 GHz amateur band were dip-switch selectable

They weren't even pretending to hide it. The product listings showed which channels were selectable and it looks like the dip switches were easily accessible:

https://hobbyking.com/en_us/1-2ghz-mg-500mw-8ch-a-v-wireless...

Wow that could have affected WAAS GPS approaches for aircraft which is rather critical stuff. (WAAS approaches allow for airplanes to descend to much lower altitudes without ground visibility. Basically the GPS equivalent of the Instrument Landing System.)

And Mode S has serious implications for TCAS systems (preventing air to air collisions.)

Extremely bad to be messing with those frequencies. Potentially catastrophic.

> Extremely bad to be messing with those frequencies. Potentially catastrophic.

If someone with a hobby electronics kit can cause that much damage, the system needs to change. Hobby projects like this can help expose the serious flaws in aircraft control, making us all safer.

Security by obscurity is no security at all. Security by hoping people don't do bad things is even worse.

Youre expected not to board a plane with a bomb and youre expected to not operate equipment on wrong frequencies that interfere with others.

Just because you can do something does not mean its ok to do.

I think what the comment is about is that the system should be built safer with less security with obscurity but more actual measures. You can (partially) scan people getting onto the plane for bombs etc but it's practically very hard to pinpoint a jamming RF transmitter possibly from kilometers away from ground. Security shouldn't rely on those frequencies being clear.

> Youre expected not to board a plane with a bomb

And we have a lot of controls around this! Congrats! You've discovered airline security!

> expected to not operate equipment on wrong frequencies that interfere with others

If I can build a small electronic device, that goes through no controls, and can cause catastrophic damage, that is a HUGE problem.

> Just because you can do something does not mean its ok to do.

lol, you missed the point. If it's that easy to do something, the system needs to change.

Because aircraft systems are multiply redundant, there is little likelihood of a jammer directly causing an accident.

However, any deterioration in that redundancy is considered a serious safety risk and immediate action is usually taken.

Bottom line: The high redundancy is there to prevent accidents, however any idiot who compromises that redundancy deserves to learn an expensive lesson.

Building jam resistant navigation radios would require too much power to be practical. The real transmitters are too far away.

This system does not at all rely on security by obscurity.

This system relies on safety be reliability / availability. All of the operating parameters are public, to prevent anyone from accidentally interfering with these systems. They are not designed against adversarial attacks, and really with radio systems. It is very hard to defend against jamming attacks. Doing so successfully makes the system a lot more complicated. More importantly, doing so successfully makes the system use much more bandwidth.

Bandwidth is actually really scarce. If you start doing defensive stuff, then more and more frequencies get used, and you end up with everyone screaming over each other just to be able to add all the required error correction. That is why we decided to coordinate on frequency allocation. It prevents a tragedy of the commons. As a side effect, it also means transmit power can be lower. This allows you to operate more systems in the same area without interfering.

Now, this does leave a somewhat fragile system. Because jamming (and other attacks) are not mitigated by the system. But this is an acceptable price to pay to actually allow people to use radio communication.

Besides, jamming attacks have an interesting downside. They are somewhat easy to track down. The higher level attacks can be defeated by cryptography. There is a mid-level of smart jamming, that attacks the low level protocols with more than just power. These require significant effort to develop though. And military hardware tends to have mitigations against this sort of thing. A sufficiently sophisticated attacker could disrupt civil systems, but to what gain?

> They are not designed against adversarial attacks

> Now, this does leave a somewhat fragile system

Thank you for reiterating my point. If such a system is not designed to stop adversarial attacks, and is a fragile system, something needs to change.

I appreciate you trying to explain why it's fragile, but it doesn't negate the risk.

It doesn't. Jamming TCAS or ILS systems doesn't cause crashes. At worst, a go-around and increased workload in the Tower.

But since you're disabling safety equipment or their redundancies, in practise it's rightfully treated as harshly as it is. TCAS almost never activates in practise but if your HAM radio jams it and a crash happens... You disabled that redundancy to prevent accidents.

> You disabled that redundancy to prevent accidents

Damn, this sounds like a huge risk. Kinda like the risk I mentioned in my first comment.

All that for a dip switch that isn't normally accessible?

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