Australia's communications regulator, ACMA, has already permitted Wi-Fi 6E devices to operate in the lower 6 GHz band (5925–6425 MHz) under the Low Interference Potential Devices (LIPD) Class Licence. This includes low-power indoor (LPI) and very low power (VLP) devices.
As for the upper 6 GHz band (6425–7125 MHz), ACMA is still evaluating its use. In June 2024, it sought public input on possible applications, including RLANs and wide-area wireless broadband services.
So, while unlicensed device operations are allowed in the lower 6 GHz band, the upper band is still under consideration.
AM radio, FM radio, amateur radio, and television broadcast have quite a lot of spectrum real estate. Are they being used enough to justify this allocation?
Is the gain in bandwidth for your wifi really worth the reallocation?
This change opens up 1200 MHz of bandwidth between 5.925 and 7.125 GHz.
Amateur radio is scattered all over the place, but excluding radio satellite they are mostly bellow 300 MHz... ignoring the fact that they are tiny slices, the upper limit of bandwidth you can hope to gain under that frequency is 300 MHz. In reality there are thousands of other allocations at those frequencies so you could never hope to allocate anything close to that, and the allocations for amateur radio are so tiny they are negligible for something like wifi, and you would never be able to use them because they are not contiguous bandwidths.
The higher the frequency the more bandwidth is available.
Some of that is because those frequencies have special characteristics, e.g., extreme long range propagation. Would you like to have a wifi router that gets interference from 300 km away or requires a certain geomagnetic storm to connect to your ISP?
Television in particular seems ripe to be reallocated. Didn't we go through a whole analog-to-digital conversion over a decade ago that led to TV going through wires instead of through the air?
I wonder if this is going to be the distraction to suggested changes in 900MHz.
My other guess is the major uses of this will turn out to be UWB related:
https://en.m.wikipedia.org/wiki/Ultra-wideband
Which in practice is largely about short range location finding.
I too have been watching the 900 MHz stuff as I have a number of unlicensed long range devices (1W ERP) that work in that range. The paranoid folks believe the FCC is trying to move all of the unlicensed stuff into the GHz+ range to limit long range communications. I don't subscribe to that opinion, I expect however that there is pressure from commercial interests on UHF and VHF frequencies.
I also believe you are correct in that the bulk of the use of the 6 GHz band will be UWB related and folks will exploit the multi-GSPS ADCs and DACs that are on Xilinx's RFSOC and Analog Devices is shipping. I read a pitch for a UWB "HD video extender" which was basically connecting a 4K display over UWB to a source rather than via a cable. That idea became a lot more viable with the current FCC order.
>The paranoid folks believe the FCC is trying to move all of the unlicensed stuff into the GHz+ range to limit long range communication
Whether or not people are paranoid, if the FCC moves all unlicenced frequencies into the GHz range, they limit the public's ability to communicate over long ranges with unlicensed equipment.
Easy calculated move; try explaining that shrinking of freedom to today's layperson. There are shades of this in understanding when and why to use VPNs and distributed filesharing (e.g. torrents as part of long-term archival efforts), versus easy smear campaign by those wishing to suppress it.
Today's WiFi, that you all know and love, started out on unlicensed RF (radio frequency) bands. We need to continue to expand the ability to talk on RF to allow innovation, like what happened with WiFi.
It's pretty damn tough to hide RF, and if it's illegal then it will ask require home brewed circuitry which pretty effectively eliminates the capability from the public
Selling the amateur/LoRaWAN spectrum to a private company for more cellular bandwidth. And, ostensibly, a terrestrial GPS backup that operates concurrently with those cellular functions, but that's a red herring in my opinion, it's basically a land-grab of public unlicensed frequencies to lease out to Verizon/ATT/Tmobile.
A current proposal regarding the 900MHz band, primarily put forward by NextNav, suggests a significant reorganization of the spectrum to allocate a portion for their terrestrial 3D positioning network, potentially creating dedicated uplink and downlink bands within the lower 900MHz range, which could impact existing users like toll systems and RFID devices due to potential interference concerns; however, this proposal faces strong opposition from various industries currently utilizing the band
14 dBm EIRP = 25 milliwatts, typical legal max for wifi, and the -5 dBm/MHz EIRP power spectral density says that 25 mW must be spread over an 80 MHz channel.
the only real limit is until you start interfering with other people to the point they notice and complain. it's not like the FCC has vans roving the streets looking for unlicensed TV usage like the BBC but for wifi.
They aren't sniffing around residential homes unless they have a reason to suspect someone is interfering with someone else's licensed spectrum, but if you're _selling_ a device that doesn't comply with the legal limits they will see you in court.
The FCC does hunt down illegal AM/FM broadcast transmitters in residences. They publish several forfeiture orders every month for pirate radio stations (often in residences,) whether their interfering or not. Hunting these is lucrative business given the PIRATE Act (S.1228) and its hefty fines.
I've never seen this happen for a WiFi band operator, so yeah, they're aren't looking. They certainly could though: someone is using all those grey market boosters. Some of those have enough power to show up for many miles, and triangulating them is quite easy.
They do go after cell jammers. One example from 2016 was a guy in Florida using one in his car during his daily commute. People complained their signals failed at about the same time every day and the FCC pursued it and caught him. $48K fine.
One reason regulations like this exist is to save people the burden of having to worry that some asshole will suddenly start transmitting in a way that interferes with you and you’ll have to go to the trouble of complaining. You can proceed on the general assumption that other people will be acting within the agreed limits.
It’s a very selfish attitude to take to say ‘Ah, I’ll just crank up the gain til someone complains’ rather than ‘I guess I’ll stick within the guidance so I don’t inconvenience anyone’.
This site is called Hacker News. It's a place where people like to tinker, poke, prod, probe things to see what it is they can do with it. It's pretty fundamental to take something and see if you can make it go to 11. There are ramifications to some of these "hacks". Knowing that and how to avoid getting caught is part of the DNA of the hacking ethos. Sometimes, your hack is harmless. Sometimes, it is slightly annoying. Sometimes, it is flat out illegal. Knowing exactly (or trying to find out) how far you can bend without breaking is part of the culture.
Once again, I say that you can push your TX higher than "accepted" and for the most part get away with it. If you push it higher to have negative consequences on other people (especially those other hackers that feel slighted) will seek to fix the glitch.
I'm really confused on how this original comment is so lost on here.
Others have already covered the legal problems with this. I’ll add that going over 1W or even less with typical WiFi gear can introduce enough distortion to offset the power gains.
WiFi hardware is cost optimized. It’s likely that the PA chips in your radio are going to distort if pushed past the legal limits. Many radios distort heavily past 100mW.
Its common for people to turn the power setting all the way up thinking they’re getting the best performance, but best performance might occur at a lower setting.
Someone trained/learned/schooled in this stuff might know that. But for a curious hacker getting at the internals of how something works, the first instinct is to turn it up. That's their learning path. It's natural curiosity. More must be better. Louder must be better.
The point is to stop scaremongering about letting people turn up the TX. It's just a damn WiFi radio. They aren't going to be blocking their neighbor from listening to their favorite ClearChannel session of commercials. At most their neighbor might get a bit of interference. But if you're running on the same channel as your neighbor, you're already asking for trouble. Nobody's going to emergency, nobody's going to jail. We're not talking about firing up an 100kW flame thrower of a radio signal here. Let's just everyone keep their knickers on and realize the context of what we're discussing
Translated the linearity of your PA (nevermind LNA for RX) is unlikely to support even 20dBm, and the higher rate modulations for even 802.11a/g (nevermind any MIMO/SDMA workings) are EVM limited, not received power limited
Ha. My friend and I had the FCC van roving our neighborhood looking for us once, back in the late 70s. A guy with a CB base station dropped a dime on us, cause we were playing with our 0.1 watt walkie talkies near his house. The guy that sold us the handhelds said “what channel crystal do you want, how about 9?” and we said sure; we didn’t know that 9 is the emergency CB channel and the law prevents its use for, for example, playing hide and seek as a 13 year old.
Of all of those hypothetical "if you could go back in time" situations, I'd want to go back and rat that guy out for selling kids that crystal.
Just the other day in another thread there was the conversation about mischievous people doing things, and that pretty much sounds like what that guy was doing. He got the best of both worlds knowing he was going to cause some chaos but none of the repercussions of it.
To be fair, there are a lot of people in the FPV drone community using 600mW+ 5ghz transmitters for analog video without HAM licenses, and I don't think I've ever heard of anyone getting in trouble for it. But that's typically in unpopulated areas.
To quote that PDF as it was a bit hard to find within the many dozens of pages:
Pg. 95: Very Low Power Device. For the purpose of this subpart, a device that operates in the 5.925-6.425 GHz and 6.525-6.875 GHz bands and has an integrated antenna. These devices do not need to operate under the control of an access point.
Pg. 98: Geofenced Very Low Power Access Point. For the purpose of this subpart, an access point that operates in the 5.925–7.125 GHz band, has an integrated antenna, and uses a geofencing system to determine channel availability at its location.
Most newer band definitions specify the limits less in wattage and more in EIRP that measures the actual output of the antenna instead of just the power applied to the antenna by the transmitter. They also specify how the power as to be spread through out the channel and how sharply it has to fall off outside the channel. [0]
[0] See page 3 for an example definition of a VLP definition and requirements from earlier this year. It specifies EIRP and how the power has to be distributed so you're not throwing one big spike in the middle of the channel for example.
> The Further Notice sought comment on the appropriate power levels as well as other rules for VLP devices to ensure that the potential for causing harmful interference to incumbent operations is minimized. (6 GHz Further Notice, 35 FCC Rcd at 3940-42, paras. 236-43.)
I feel like limits on EIRP are overly conservative and restrict the usefulness of phased arrays. If the limit were on total radiated power, then your 1 watt WiFi router could have the range of a kilowatt transceiver with a reasonable number of antenna elements, while emitting the same total power as interference. But since the limit is on EIRP, the phased array is limited to the same range, and so there's no point in using a phased array over a single antenna.
Does anyone know if there's a good reason to use EIRP that I'm missing? I figure satellite communication terminals can have huge EIRPs because they're all pointed at the sky, but the FCC can't guarantee that the beams won't cross for other bands, so they limit the EIRP, but I still think we would all be better off of our systems were spatially selective.
If you use a directive antenna to concentrate the radiated power into a small solid angle, to reach a distant receiver, you also increase in the same proportion the interference for another receiver that is located in the same direction as yours, but which does not want to receive your signal.
So limiting EIRP provides a limit for the interference suffered by a receiver that happens to be in the direction towards which you transmit, for which it does not matter at all which is the total power that you transmit in all directions.
True, but it dissuades folks from using directional signals, broadcasting RF energy in more directions and increasing the noise floor for everyone. I feel like there should be some sort of middle point here.
Directional signals are easy to use only when both the access points and the wireless stations are in fixed locations.
When this is true, it is trivial to use classic directive antennas to achieve very long range communications with standard WiFi. There is no need for expensive phased array antennas.
For mobile stations and/or access points, phased array antennas are not enough. See my other reply.
WiFi, Bluetooth and the other kinds of communication protocols standardized for use in the unlicensed bands are intended mainly for cheap mobile devices, and mobility at a modest price restricts the antennas to be omnidirectional.
EIRP is good at reducing uintentional interference. After all, you'd probably wouldn't like me pointing a 20 element yagi antenna through your house, denying your ability to use the spectrum in a reasonable manner, just so I could do a point-to-point fixed link.
EIRP minimizes regulations. It's a good trade-off over operator and installation licencing.
Modern MIMO is about utilizing the combined channel efficiently, not necessarily beam forming. In most cases you can still extract more capacity from a channel with two or more antennas within the same EIRP envelope as a single antenna.
Yes, for the same reason that I can look into a 5mW LED but 5mW of laser can blind me. Your neighbour's WiFi routewr might be entirely DoS'd by the Maser of RF coming through the wall at it from your phased array, even thoughh it's only 100mW.
Sure, but the probability would be low-ish of that happening, and the other system could either switch frequencies or beamform a null in the direction of the interferer if they were also a phased array.
Maybe the EIRP shouldn't be unlimited, but I still think it would be beneficial to encourage spatially selective systems.
In an unlicensed band, everyone may have receivers and transmitters, so the probability of other receivers in the same direction as yours is not low at all, but it is very high, unless you live in the middle of nowhere, so you do not have neighbors.
There is no justification for imposing additional costs for others in order to accommodate your desires that do not matter for them.
Nobody stops you to use a phased array antenna only to obtain a higher gain for reception, in order to increase the communication range.
Even without phased array antennas, using just classic directive antennas that are placed on high masts, it is possible to communicate through WiFi at tens of km (but only at low bit rates and not in all countries, as some have more severe EIRP limits).
The problem of directive antennas is that they are usable only for fixed positions of access points and wireless stations.
Phased array antennas are not enough to enable mobility, because initially a mobile wireless station must discover the direction of the AP and the AP must discover the direction of the station, by using omnidirectional transmission, which limits the range to what can be achieved without phased array antennas.
To use a mobile wireless network that works at distances greater than possible with omnidirectional antennas requires much more sophisticated equipment than just the phased array antennas. You also need means to determine the coordinates of each station (and of the access points, if they are also mobile) and maps with the locations of the access points so that a station that wants to associate with them will know in what direction to transmit. You also need a protocol different from standard WiFi, e.g. the access point may need to scan periodically all directions in order to allow new associations from distant stations.
> so the probability of other receivers in the same direction as yours is not low at all, but it is very high
But on average, even with unlimited EIRP, I'll see 1/n as many interfering signals that are each n times as strong. That's not a bad tradeoff.
But having a moderate EIRP increase for focused signals would make things better for everyone. Let's say a signal that's 10x as focused can have 3x the EIRP, and everyone switches their equipment over. That drops the total power output by 3.3x, and interference drops significantly for almost everyone.
> initially a mobile wireless station must discover the direction of the AP and the AP must discover the direction of the station, by using omnidirectional transmission, which limits the range to what can be achieved without phased array antennas
You can do discovery at a lower bit rate to get a big range boost.
For a radio receiver it is irrelevant how many interfering signals exist.
The only things that matter are the radiant intensity (i.e. power per solid angle) of the interfering transmitter and the percentage of the time when that transmitter is active.
A single interfering transmitter with high radiant intensity (a.k.a. EIRP) will blind the radio receiver for all the time when it is active.
Doing discovery at a low bit rate is fine, but that means that your fancy phased array antenna cannot achieve any higher distance for communication than an omnidirectional antenna, but it can only increase the achieved bit rate at a given distance.
That would be OK, except that it is achieved by interfering with your neighbors, exactly like when using a transmitter with a higher total power than allowed.
Limiting EIRP is the right thing to do in order to limit the interference that you can cause to your neighbors.
The law does not stop you to use a phased array antenna or any other kind of directive antenna, with the purpose of lowering the power consumption of your transmitter, while maintaining the same quality for your communication and the same interference for your neighbors.
What you want to do, i.e. increase the interference for your neighbors, is the wrong thing to desire. If that were allowed, your neighbors would also increase the radiant intensity of their transmitters and then everybody would have worse reception conditions and you would gain nothing.
The hope that only you will increase your radiant intensity and your neighbors will not, is of course illusory.
> For a radio receiver it is irrelevant how many interfering signals exist.
> The only things that matter are the radiant intensity (i.e. power per solid angle) of the interfering transmitter and the percentage of the time when that transmitter is active.
And if a transmitter isn't pointed at you, then it isn't an interfering transmitter. This is a crucial factor in the math.
Or for a more realistic analysis of directionality, the radiant intensity is only high for a small fraction of observers, and is very low for the rest of them.
In the first scenario I talked about, total interference is probably the same.
In the second, total interference is almost always much less.
> A single interfering transmitter with high radiant intensity (a.k.a. EIRP) will blind the radio receiver for all the time when it is active.
If a moderate boost blinds the receiver, then the alternative is being almost blind for much longer (because there are more interfering transmitters), so I'm not convinced that's a problem.
> Doing discovery at a low bit rate is fine, but that means that your fancy phased array antenna cannot achieve any higher distance for communication than an omnidirectional antenna, but it can only increase the achieved bit rate at a given distance.
I don't understand what you mean.
If you don't care about speed, the maximum distance is the same for both antennas, and is defined by obstacles alone.
You can always slow down to compensate for a lack of gain. And it's a proportional slowdown, not very expensive. Especially when you only need to send a beacon that's a few bytes long to initiate contact.
Just some example numbers: Your functional requirements are 1Mbps of bandwidth with pretty tight focus. You send the few bytes of initial omnidirectional contact at 1Kbps. Your slow omnidirectional signal actually reaches further than your fast focused signal.
> Limiting EIRP is the right thing to do in order to limit the interference that you can cause to your neighbors.
If your only concern is the worst case of everyone being pointed at the same spot, yes. In normal situations the average level of interference matters more.
> The law does not stop you to use a phased array antenna or any other kind of directive antenna, with the purpose of lowering the power consumption of your transmitter, while maintaining the same quality for your communication and the same interference for your neighbors.
The law says that I can maintain quality and decrease interference, but I don't gain any real benefit because I'm only saving half a watt. So I'm not very motivated to do so. I'd prefer if it was legal to split the difference between increased signal quality and somewhat decreased interference.
> What you want to do, i.e. increase the interference for your neighbors, is the wrong thing to desire.
Where do you think I said that?
Edit:
> your neighbors would also
Here, I'll elaborate on a scenario.
Originally, me and my 6 neighbors are all transmitting omnidirectionally and causing 1 unit of interference to each other person. Everyone gets 6 units of interference.
I want to lower my transmit power but double my EIRP. I am entirely selfishly motivated, and just want a better signal to my devices. As a consequence I will now cause 2 units of interference to a single neighbor, and 0.1 units of interference to all other neighbors.
What happens when everyone thinks this way and does the same thing? Well now the neighborhood receives 2.5 units of interference on average instead of 6. Even with a bit of variance as devices move around, everyone is better off now. I love that my neighbors did the same thing I did.
This (and the parent) really sound super interesting to me, but I don't understand. Before I spend hours on Wikipedia reading about EIRP and phased array (and probably give up), is there a chance one of you could explain this briefly in words I may understand? :)
A phased array is capable of "beamforming", that is, sending an electromagnetic signal most strongly in a specific, programmable direction, as opposed to broadcasting the signal in many or all directions.
EIRP is a measure of the maximum power in any direction, so a phased array that transmits 1W only forward has the same EIRP as an omnidirectional antenna that transmits 1W forward, but also 1W backward, and up, and down, etc. Overall the omnidirectional antenna may transmit much more power total, but still only 1W in any particular direction.
EIRP adjusts the total radiated power for the antenna gain.
So if you're transmitting 1 W and your antenna has a gain of 30 dBi (1000x), that's equivalent (from the perspective of whatever it's pointed at) to an isotropic antenna (no gain) emitting 1000 W at the same distance.
It should be obvious that EIRP is what matters for interference and human safety, hence why the FCC regulates EIRP instead of power output.
A phased array is a very high-tech method of selective transmission so that you can send a radio signal that is stronger in one specific direction. The way I think of it is that it creates a virtual directional antenna where the direction is adjustable without actually physically moving the antenna elements. The actual tech involved is pretty heavy math and physics (and I don't fully understand it myself) so if you want to really understand it then you may still need to spend hours reading about it.
I feel like the barrier may be whether dedicated hardware is required or not. In such a large band, 6 GHz, I would expect a lot of generalized (i.e. non-dedicated) platform hardware to be developed & offered allowing software-focused innovators to offer into the long tail of applications, including mesh network(s).
Everyone I've talked to from the LORA crowd and even some (LORA) alliance guys tells me lo-energy meshes are hard to get right. Am I missing something?
I wonder if ESP-NOW[0] would be useful for this. I've been toying with building some mesh-based lighting controllers for synchronizing lights. Fortunately it can be entirely static (number of nodes) which makes it an easier problem than dynamic meshes.
Mesh networks are a neat idea, but the reality of is often disappointing e.g. given compatible radios all the IoT devices in a room could form a mesh network of equal peers, but if a few lightbulbs use their position (mains powered, good location) to form a hierarchical network it will actually work (without wasting battery power and air time).
This feels very pie in the sky and dreamlike. Of course some corp will figure out something to do within this space and make closed products that push out free and open uses. At least that's my pessimistic view opposed to your optimism.
If you pop open a spectrum analyzer in most places, you'll see a ghost town in the Cathedral and a hopping lively Bazaar in 2.4/5GHz. On net, it is good that more resources are going to the Bazaar.
6ghz is pretty fragile -- i can't imagine one product "pushing out" another when a wall will block the signal. Just don't have the closed products in your home, and the open ones should work just fine...
> The Commission envisioned that body-worn devices would make-up
most VLP device use cases and that these devices would provide large quantities of data in real-time. Entities that support the Commission permitting VLP device operation expect that these devices will support portable use cases, such as wearable peripherals (e.g., smartphones, glasses, watches, and earphones), including augmented reality/virtual reality and other personal-area-network applications, as well as in-vehicle applications (e.g., dashboard displays).
Looks like it does not allow new channels for 6 GHz Wi-Fi. 802.11be (Wi-Fi 7) already covers full range of FCC's allowed frequency range. IEEE committee may add new channels in 802.11bn (expected to be ratified around 2028, and commercial name will be Wi-Fi 8) but it also looks like a low probably, considering both 802.11ax (Wi-Fi 6/ Wi-Fi 6e) and 802.11be (Wi-Fi 7) mostly focuses on reducing the interference between different networks by reducing the collision, instead of widening the spectrum (BSS coloring, Flexible Channel Utilization etc.)
The alleged/misunderstood "fragility" can be exploited though. A lot of residential walls are gypsum board, which contains a lot of water, and attenuates microwave signals.
Rather than fight this by trying to shout as loud as you can from a single AP across the house, you can put smaller, weaker APs in multiple rooms. Because of the excellent open air penetration and high frequency, you can get a multi-gig links with no interference or competition.
It's line of sight only. Think about it like a flashlight. If you have a flashlight (w/power) up on top of a skyscraper roof or a mountainside it can be seen at very long distances. At street level it goes till the next small rise in the ground.
Range for the newly-available parts of the 6 GHz band will not be substantially different from range for the 5 GHz band and the portions of the 6 GHz band that were already available for uses like WiFi.
> It is a holiday miracle for small low power handheld devices.
Is it really? Isn't the signal blocked if a person simply walks between he devices? i.e. if you are wearing a receiver and just turn around you will lose connection.
I hope other jurisdictions follow suit so hardware using it can be cheaper due to economies of scale. The segmentation of LoRA radios between US/EU is already pretty annoying and they're fairly niche.
Satellite communications, point-to-point microwave systems, and other similar things (high-data-rate, point-to-point communication) all operate near this band. However, there's plenty of spectrum and the use cases may be declining. There were also some radar systems in this band, but IIRC the useful new radar systems are higher-frequency (10's of GHz for resolution) or lower-frequency (10's-100's of MHz to have longer range).
I wonder if this was in motion for a while and then intentionally accelerated to ensure it happens under Biden.
Optically it's a pretty pure win. Open stuff sounds good. Less regs sounds good. Tech sounds good. And it's not something that has a corresponding voting block opposing. Just pure upside politically.
Is there any merit to non-ionizing frequencies having harmful impacts on human biological function, I thought so, but is it all "conspiracy" and laughed out of the room or a legitimate scientific part of these discussions?
I'm not a physicist or biologist but what's always made sense to me is that anytime you walk outside during the day you are bathed in broad spectrum radiation from the sun. So anything weaker than the sun is probably safe enough. Anything a million or billion times weaker is probably a million or billion times safer. We already know when and how radios get dangerous (large transmission towers, microwave ovens, etc) and how to mitigate that danger. Inverse cube law and somesuch.
The sun is damaging because it contains ionizing radiation (radiation that is powerful enough to directly disassociate a molecule into ions). This is the UV portion of sunlight.
UV starts at 800,000 GHz.
The 6Ghz being discussed here is completely non-ionizing, not even comparable to UV.
The only concern with 6Ghz is that is can also cause dielectric heating, which is the same as a microwave. But again, at 25mW, you can't even feel the heat from direct contact with the antenna, let alone a few meters away. Your exposure follows the inverse-square law [1], which means that it drops proportional to the square of the distance. So if it's not a problem at 10cm, it's 100x less of a non-problem at 1m.
evolutionary argument is humans are aligned with broad spectrum radiation from the sun, but not the artificial forms which have different magnitudes in different frequencies.
Eg: you are much less likely to get sunburn if you get plenty of natural (or artificial) infrared.
There is no such thing as artificial forms of RF. They're all wiggling photons.
If nature gave us a flute, and man discovered how to make a bass guitar, all though they sound different the only real difference is that the bass guitar is wiggling air molecules more slowly than a flute would. There is zero, nil, no distinction whatsoever between a "natural" and "synthetic" photon wiggling at a given frequency.
> you are much less likely to get sunburn if you get plenty of natural (or artificial) infrared.
Microwave frequencies can harm biological function through heating tissue; in particular eyeballs have lots of water and poor ability to dissipate heat. However, very low power densities are almost certainly safe.
[edit]
Another example of non-ionizing radiation harming human tissue would be if you stick your hand in front of a cutting laser. Maybe obvious, but you asked...
Most concerns focus around the electromagnetic radiation heating your tissue. Microwave ovens operate at 2.4MHz, and most common frequencies can work like a microwave with varying efficiency. At the intensities of normal transmissions that isn't really a concern. For a time this seemed like something we might worry about with phones, since during a phone call there we have an active antenna right next to your fairly sensitive brain that might not like being heated up. But even there it turned out that the effect was too small to be of concern
Ham radio operators do need to worry about radio exposure safety for heating. But we are using much higher powers, 100W is normal HF radio, and 1500W is the limit. 5W handheld next to head is safe. Also, the
There’s none other than localized heating effects, and yes, it’s laughed out of the room.
So, obviously you don’t want to microwave your eyeballs, but you’d feel that in other nearby tissues as heat. If you don’t feel heat from a non-ionizing RF source, you’re not getting cooked. In any case, the amount of infrared coming off an incandescent lightbulb is about 3 orders of magnitude higher than the energy coming off a WiFi router antenna. If being in the room with a lightbulb is safe, so is being in the room with WiFi.
There isn’t a set of rules of physics where low-power, non-heating, non-ionizing RF is dangerous, and also where CPUs work. They’re incompatible. You can’t have both of those at the same time.
We honestly don’t know. Current safety standards mostly focus on preventing tissue heating, because that’s the one effect we can reliably measure and understand. But there’s a chunk of exploratory research out there looking at potential “non-thermal” effects—things like subtle shifts in cell signaling, membrane permeability, or oxidative stress—that might not show up as a measurable temperature increase.
So far, the studies that have been well-designed and replicated haven’t consistently nailed down a clear causal link between non-thermal EMF exposure (within the limits that regulators consider safe) and actual health problems. Still, some researchers argue that we’re not accounting for all the slow-burn, cumulative effects that might be happening. It’s not easy to tease out these subtle influences from the noise of environmental variables, and that makes it hard to really say we’ve got a handle on the whole picture. Check out Prof Michael Levin's Bioelectricity work if you want to go down a very interesting rabbit hole about what we're only recently discovering about how our biology might really work and how electricity and emf's shape it.
With a large enough antenna and enough power you can cook your neighbor.
The ham radio licensing procedure in the US mostly focuses on this effect. Even though there's nothing conclusive I'd imagine there are other deleterious effects that aren't trivially measurable. If it can heat it up it can do other stuff too. Cooking your brain by standing too close to a high power transmission tower can't be good.
I'm an amateur extra, I would challenge any "scientist" laughing EMF dangers off to go find the nearest AM radio tower and spend 6 months in the transmission room for "science".
Without sarcasm, the studies I have found over the years ruled out cumulative effects (unlike ionizing radiation). They so far haven't been able to rule out various types of cancer, ALS, or other diseases caused by long-term exposure.
This is cool, I hope Australia follows suit!
Australia's communications regulator, ACMA, has already permitted Wi-Fi 6E devices to operate in the lower 6 GHz band (5925–6425 MHz) under the Low Interference Potential Devices (LIPD) Class Licence. This includes low-power indoor (LPI) and very low power (VLP) devices.
As for the upper 6 GHz band (6425–7125 MHz), ACMA is still evaluating its use. In June 2024, it sought public input on possible applications, including RLANs and wide-area wireless broadband services.
So, while unlicensed device operations are allowed in the lower 6 GHz band, the upper band is still under consideration.
Chart of all US frequency allocations (as of 2016, but there doesn't appear to be a more up to date one?): https://www.ntia.gov/sites/default/files/publications/januar...
The most current document is here, but it's text.
https://www.fcc.gov/sites/default/files/fcctable.pdf
AM radio, FM radio, amateur radio, and television broadcast have quite a lot of spectrum real estate. Are they being used enough to justify this allocation?
Is the gain in bandwidth for your wifi really worth the reallocation?
This change opens up 1200 MHz of bandwidth between 5.925 and 7.125 GHz.
Amateur radio is scattered all over the place, but excluding radio satellite they are mostly bellow 300 MHz... ignoring the fact that they are tiny slices, the upper limit of bandwidth you can hope to gain under that frequency is 300 MHz. In reality there are thousands of other allocations at those frequencies so you could never hope to allocate anything close to that, and the allocations for amateur radio are so tiny they are negligible for something like wifi, and you would never be able to use them because they are not contiguous bandwidths.
The higher the frequency the more bandwidth is available.
Some of that is because those frequencies have special characteristics, e.g., extreme long range propagation. Would you like to have a wifi router that gets interference from 300 km away or requires a certain geomagnetic storm to connect to your ISP?
Television in particular seems ripe to be reallocated. Didn't we go through a whole analog-to-digital conversion over a decade ago that led to TV going through wires instead of through the air?
The digital signals are still radio-carried, but yes, that would technically allow condensing the spectrum some.
No, AM radio are low RF frequency and have little spectrum for data transmission. also due to long range it will be severely interference limited.
I wonder if this is going to be the distraction to suggested changes in 900MHz.
My other guess is the major uses of this will turn out to be UWB related: https://en.m.wikipedia.org/wiki/Ultra-wideband Which in practice is largely about short range location finding.
I too have been watching the 900 MHz stuff as I have a number of unlicensed long range devices (1W ERP) that work in that range. The paranoid folks believe the FCC is trying to move all of the unlicensed stuff into the GHz+ range to limit long range communications. I don't subscribe to that opinion, I expect however that there is pressure from commercial interests on UHF and VHF frequencies.
I also believe you are correct in that the bulk of the use of the 6 GHz band will be UWB related and folks will exploit the multi-GSPS ADCs and DACs that are on Xilinx's RFSOC and Analog Devices is shipping. I read a pitch for a UWB "HD video extender" which was basically connecting a 4K display over UWB to a source rather than via a cable. That idea became a lot more viable with the current FCC order.
>The paranoid folks believe the FCC is trying to move all of the unlicensed stuff into the GHz+ range to limit long range communication
Whether or not people are paranoid, if the FCC moves all unlicenced frequencies into the GHz range, they limit the public's ability to communicate over long ranges with unlicensed equipment.
Easy calculated move; try explaining that shrinking of freedom to today's layperson. There are shades of this in understanding when and why to use VPNs and distributed filesharing (e.g. torrents as part of long-term archival efforts), versus easy smear campaign by those wishing to suppress it.
I'll take a crack:
Today's WiFi, that you all know and love, started out on unlicensed RF (radio frequency) bands. We need to continue to expand the ability to talk on RF to allow innovation, like what happened with WiFi.
Unless the public devises ways to use sub-ghz frequencies without getting caught.
It's pretty damn tough to hide RF, and if it's illegal then it will ask require home brewed circuitry which pretty effectively eliminates the capability from the public
What are the suggested changes?
Selling the amateur/LoRaWAN spectrum to a private company for more cellular bandwidth. And, ostensibly, a terrestrial GPS backup that operates concurrently with those cellular functions, but that's a red herring in my opinion, it's basically a land-grab of public unlicensed frequencies to lease out to Verizon/ATT/Tmobile.
I found this:
A current proposal regarding the 900MHz band, primarily put forward by NextNav, suggests a significant reorganization of the spectrum to allocate a portion for their terrestrial 3D positioning network, potentially creating dedicated uplink and downlink bands within the lower 900MHz range, which could impact existing users like toll systems and RFID devices due to potential interference concerns; however, this proposal faces strong opposition from various industries currently utilizing the band
I work with some of that RFID/Tolling equipment and I can tell you this would be very bad news for a lot of industries.
But will UWB be allowed to have a higher EIRP in this band?
The news release doesn't say what qualifies as very low power. There's a definition at https://docs.fcc.gov/public/attachments/DOC-397315A1.pdf.
14 dBm EIRP = 25 milliwatts, typical legal max for wifi, and the -5 dBm/MHz EIRP power spectral density says that 25 mW must be spread over an 80 MHz channel.
> 25 milliwatts, typical legal max for wifi
AFAIK wifi can use more power than that, at least in the US: 100mW, possibly 200mW, not sure what the hard limit is (or how much that must be spread).
I'm pretty sure you can run 1 watt on WiFi.
1 watt conducted power, 4 watts EIRP. For most of the world, the ETSI limit is 100mW EIRP.
https://www.ecfr.gov/current/title-47/chapter-I/subchapter-A...
the only real limit is until you start interfering with other people to the point they notice and complain. it's not like the FCC has vans roving the streets looking for unlicensed TV usage like the BBC but for wifi.
They aren't sniffing around residential homes unless they have a reason to suspect someone is interfering with someone else's licensed spectrum, but if you're _selling_ a device that doesn't comply with the legal limits they will see you in court.
The FCC does hunt down illegal AM/FM broadcast transmitters in residences. They publish several forfeiture orders every month for pirate radio stations (often in residences,) whether their interfering or not. Hunting these is lucrative business given the PIRATE Act (S.1228) and its hefty fines.
I've never seen this happen for a WiFi band operator, so yeah, they're aren't looking. They certainly could though: someone is using all those grey market boosters. Some of those have enough power to show up for many miles, and triangulating them is quite easy.
They do go after cell jammers. One example from 2016 was a guy in Florida using one in his car during his daily commute. People complained their signals failed at about the same time every day and the FCC pursued it and caught him. $48K fine.
This is a sad approach to legal compliance.
One reason regulations like this exist is to save people the burden of having to worry that some asshole will suddenly start transmitting in a way that interferes with you and you’ll have to go to the trouble of complaining. You can proceed on the general assumption that other people will be acting within the agreed limits.
It’s a very selfish attitude to take to say ‘Ah, I’ll just crank up the gain til someone complains’ rather than ‘I guess I’ll stick within the guidance so I don’t inconvenience anyone’.
This site is called Hacker News. It's a place where people like to tinker, poke, prod, probe things to see what it is they can do with it. It's pretty fundamental to take something and see if you can make it go to 11. There are ramifications to some of these "hacks". Knowing that and how to avoid getting caught is part of the DNA of the hacking ethos. Sometimes, your hack is harmless. Sometimes, it is slightly annoying. Sometimes, it is flat out illegal. Knowing exactly (or trying to find out) how far you can bend without breaking is part of the culture.
Once again, I say that you can push your TX higher than "accepted" and for the most part get away with it. If you push it higher to have negative consequences on other people (especially those other hackers that feel slighted) will seek to fix the glitch.
I'm really confused on how this original comment is so lost on here.
i mean, to some people the FCC is the overreach that represents "a sad approach to compliance":
> some asshole will suddenly start transmitting in a way that interferes with you
remember LightSquared/Ligado Networks? assholes, but with $$$ tho. still a thing:
https://news.ycombinator.com/item?id=23103290 https://www.gps.gov/spectrum/ligado/
Don't underestimate the determination of hams to find people that aren't playing by the rules on the spectrum.
again, until someone notices and complains.
i don't know why we're being argumentative here
You're interpreting what I meant to be a joke as argumentative.
read the room of the rest of the comments. also, i failed to see you used the funny font
Others have already covered the legal problems with this. I’ll add that going over 1W or even less with typical WiFi gear can introduce enough distortion to offset the power gains.
WiFi hardware is cost optimized. It’s likely that the PA chips in your radio are going to distort if pushed past the legal limits. Many radios distort heavily past 100mW.
Its common for people to turn the power setting all the way up thinking they’re getting the best performance, but best performance might occur at a lower setting.
Someone trained/learned/schooled in this stuff might know that. But for a curious hacker getting at the internals of how something works, the first instinct is to turn it up. That's their learning path. It's natural curiosity. More must be better. Louder must be better.
The point is to stop scaremongering about letting people turn up the TX. It's just a damn WiFi radio. They aren't going to be blocking their neighbor from listening to their favorite ClearChannel session of commercials. At most their neighbor might get a bit of interference. But if you're running on the same channel as your neighbor, you're already asking for trouble. Nobody's going to emergency, nobody's going to jail. We're not talking about firing up an 100kW flame thrower of a radio signal here. Let's just everyone keep their knickers on and realize the context of what we're discussing
PARP has entered the chat
Translated the linearity of your PA (nevermind LNA for RX) is unlikely to support even 20dBm, and the higher rate modulations for even 802.11a/g (nevermind any MIMO/SDMA workings) are EVM limited, not received power limited
There's a LOT of testing done, before you can sell a device, including TX power measurement.
And yes, they have vans roving the streets looking for illegal transmissions.
Ha. My friend and I had the FCC van roving our neighborhood looking for us once, back in the late 70s. A guy with a CB base station dropped a dime on us, cause we were playing with our 0.1 watt walkie talkies near his house. The guy that sold us the handhelds said “what channel crystal do you want, how about 9?” and we said sure; we didn’t know that 9 is the emergency CB channel and the law prevents its use for, for example, playing hide and seek as a 13 year old.
47 CFR 95.931(a)(2):"CBRS Channel 9 may be used only for emergency communications or traveler assistance. It must not be used for any other purpose."
Since the goal of hide and seek is to get home (before found) I’d call that traveler assistance. <grin>
Of all of those hypothetical "if you could go back in time" situations, I'd want to go back and rat that guy out for selling kids that crystal.
Just the other day in another thread there was the conversation about mischievous people doing things, and that pretty much sounds like what that guy was doing. He got the best of both worlds knowing he was going to cause some chaos but none of the repercussions of it.
I bet he had had that crystal on the shelf for a long time and he kept trying to sell it.
> And yes, they have vans roving the streets looking for illegal transmissions.
Only and when they receive complaints. Then they have to decide if it is serious enough to care. This is a far cry different than active BBC patrols.
I clearly stated until people notice and complain. It's like these words were totally ignored.
To be fair, there are a lot of people in the FPV drone community using 600mW+ 5ghz transmitters for analog video without HAM licenses, and I don't think I've ever heard of anyone getting in trouble for it. But that's typically in unpopulated areas.
Also, they are gone before anyone can triangulate them.
Not for all devices and they're not even particularly good at catching sellers who should provide testing data and register but don't.
To quote that PDF as it was a bit hard to find within the many dozens of pages:
Pg. 95: Very Low Power Device. For the purpose of this subpart, a device that operates in the 5.925-6.425 GHz and 6.525-6.875 GHz bands and has an integrated antenna. These devices do not need to operate under the control of an access point.
Pg. 98: Geofenced Very Low Power Access Point. For the purpose of this subpart, an access point that operates in the 5.925–7.125 GHz band, has an integrated antenna, and uses a geofencing system to determine channel availability at its location.
Sooo no watts or meters?
14 dBm EIRP and a power spectral density of -5 dBm/MHz EIRP.
Most newer band definitions specify the limits less in wattage and more in EIRP that measures the actual output of the antenna instead of just the power applied to the antenna by the transmitter. They also specify how the power as to be spread through out the channel and how sharply it has to fall off outside the channel. [0]
[0] See page 3 for an example definition of a VLP definition and requirements from earlier this year. It specifies EIRP and how the power has to be distributed so you're not throwing one big spike in the middle of the channel for example.
> The Further Notice sought comment on the appropriate power levels as well as other rules for VLP devices to ensure that the potential for causing harmful interference to incumbent operations is minimized. (6 GHz Further Notice, 35 FCC Rcd at 3940-42, paras. 236-43.)
I feel like limits on EIRP are overly conservative and restrict the usefulness of phased arrays. If the limit were on total radiated power, then your 1 watt WiFi router could have the range of a kilowatt transceiver with a reasonable number of antenna elements, while emitting the same total power as interference. But since the limit is on EIRP, the phased array is limited to the same range, and so there's no point in using a phased array over a single antenna.
Does anyone know if there's a good reason to use EIRP that I'm missing? I figure satellite communication terminals can have huge EIRPs because they're all pointed at the sky, but the FCC can't guarantee that the beams won't cross for other bands, so they limit the EIRP, but I still think we would all be better off of our systems were spatially selective.
If you use a directive antenna to concentrate the radiated power into a small solid angle, to reach a distant receiver, you also increase in the same proportion the interference for another receiver that is located in the same direction as yours, but which does not want to receive your signal.
So limiting EIRP provides a limit for the interference suffered by a receiver that happens to be in the direction towards which you transmit, for which it does not matter at all which is the total power that you transmit in all directions.
True, but it dissuades folks from using directional signals, broadcasting RF energy in more directions and increasing the noise floor for everyone. I feel like there should be some sort of middle point here.
Directional signals are easy to use only when both the access points and the wireless stations are in fixed locations.
When this is true, it is trivial to use classic directive antennas to achieve very long range communications with standard WiFi. There is no need for expensive phased array antennas.
For mobile stations and/or access points, phased array antennas are not enough. See my other reply.
WiFi, Bluetooth and the other kinds of communication protocols standardized for use in the unlicensed bands are intended mainly for cheap mobile devices, and mobility at a modest price restricts the antennas to be omnidirectional.
EIRP is good at reducing uintentional interference. After all, you'd probably wouldn't like me pointing a 20 element yagi antenna through your house, denying your ability to use the spectrum in a reasonable manner, just so I could do a point-to-point fixed link.
EIRP minimizes regulations. It's a good trade-off over operator and installation licencing.
It sounds like this is very definitely targeted at high speed personal-area-networks.
Modern MIMO is about utilizing the combined channel efficiently, not necessarily beam forming. In most cases you can still extract more capacity from a channel with two or more antennas within the same EIRP envelope as a single antenna.
Yes, for the same reason that I can look into a 5mW LED but 5mW of laser can blind me. Your neighbour's WiFi routewr might be entirely DoS'd by the Maser of RF coming through the wall at it from your phased array, even thoughh it's only 100mW.
Sure, but the probability would be low-ish of that happening, and the other system could either switch frequencies or beamform a null in the direction of the interferer if they were also a phased array.
Maybe the EIRP shouldn't be unlimited, but I still think it would be beneficial to encourage spatially selective systems.
In an unlicensed band, everyone may have receivers and transmitters, so the probability of other receivers in the same direction as yours is not low at all, but it is very high, unless you live in the middle of nowhere, so you do not have neighbors.
There is no justification for imposing additional costs for others in order to accommodate your desires that do not matter for them.
Nobody stops you to use a phased array antenna only to obtain a higher gain for reception, in order to increase the communication range.
Even without phased array antennas, using just classic directive antennas that are placed on high masts, it is possible to communicate through WiFi at tens of km (but only at low bit rates and not in all countries, as some have more severe EIRP limits).
The problem of directive antennas is that they are usable only for fixed positions of access points and wireless stations.
Phased array antennas are not enough to enable mobility, because initially a mobile wireless station must discover the direction of the AP and the AP must discover the direction of the station, by using omnidirectional transmission, which limits the range to what can be achieved without phased array antennas.
To use a mobile wireless network that works at distances greater than possible with omnidirectional antennas requires much more sophisticated equipment than just the phased array antennas. You also need means to determine the coordinates of each station (and of the access points, if they are also mobile) and maps with the locations of the access points so that a station that wants to associate with them will know in what direction to transmit. You also need a protocol different from standard WiFi, e.g. the access point may need to scan periodically all directions in order to allow new associations from distant stations.
> so the probability of other receivers in the same direction as yours is not low at all, but it is very high
But on average, even with unlimited EIRP, I'll see 1/n as many interfering signals that are each n times as strong. That's not a bad tradeoff.
But having a moderate EIRP increase for focused signals would make things better for everyone. Let's say a signal that's 10x as focused can have 3x the EIRP, and everyone switches their equipment over. That drops the total power output by 3.3x, and interference drops significantly for almost everyone.
> initially a mobile wireless station must discover the direction of the AP and the AP must discover the direction of the station, by using omnidirectional transmission, which limits the range to what can be achieved without phased array antennas
You can do discovery at a lower bit rate to get a big range boost.
For a radio receiver it is irrelevant how many interfering signals exist.
The only things that matter are the radiant intensity (i.e. power per solid angle) of the interfering transmitter and the percentage of the time when that transmitter is active.
A single interfering transmitter with high radiant intensity (a.k.a. EIRP) will blind the radio receiver for all the time when it is active.
Doing discovery at a low bit rate is fine, but that means that your fancy phased array antenna cannot achieve any higher distance for communication than an omnidirectional antenna, but it can only increase the achieved bit rate at a given distance.
That would be OK, except that it is achieved by interfering with your neighbors, exactly like when using a transmitter with a higher total power than allowed.
Limiting EIRP is the right thing to do in order to limit the interference that you can cause to your neighbors.
The law does not stop you to use a phased array antenna or any other kind of directive antenna, with the purpose of lowering the power consumption of your transmitter, while maintaining the same quality for your communication and the same interference for your neighbors.
What you want to do, i.e. increase the interference for your neighbors, is the wrong thing to desire. If that were allowed, your neighbors would also increase the radiant intensity of their transmitters and then everybody would have worse reception conditions and you would gain nothing.
The hope that only you will increase your radiant intensity and your neighbors will not, is of course illusory.
> For a radio receiver it is irrelevant how many interfering signals exist.
> The only things that matter are the radiant intensity (i.e. power per solid angle) of the interfering transmitter and the percentage of the time when that transmitter is active.
And if a transmitter isn't pointed at you, then it isn't an interfering transmitter. This is a crucial factor in the math.
Or for a more realistic analysis of directionality, the radiant intensity is only high for a small fraction of observers, and is very low for the rest of them.
In the first scenario I talked about, total interference is probably the same.
In the second, total interference is almost always much less.
> A single interfering transmitter with high radiant intensity (a.k.a. EIRP) will blind the radio receiver for all the time when it is active.
If a moderate boost blinds the receiver, then the alternative is being almost blind for much longer (because there are more interfering transmitters), so I'm not convinced that's a problem.
> Doing discovery at a low bit rate is fine, but that means that your fancy phased array antenna cannot achieve any higher distance for communication than an omnidirectional antenna, but it can only increase the achieved bit rate at a given distance.
I don't understand what you mean.
If you don't care about speed, the maximum distance is the same for both antennas, and is defined by obstacles alone.
You can always slow down to compensate for a lack of gain. And it's a proportional slowdown, not very expensive. Especially when you only need to send a beacon that's a few bytes long to initiate contact.
Just some example numbers: Your functional requirements are 1Mbps of bandwidth with pretty tight focus. You send the few bytes of initial omnidirectional contact at 1Kbps. Your slow omnidirectional signal actually reaches further than your fast focused signal.
> Limiting EIRP is the right thing to do in order to limit the interference that you can cause to your neighbors.
If your only concern is the worst case of everyone being pointed at the same spot, yes. In normal situations the average level of interference matters more.
> The law does not stop you to use a phased array antenna or any other kind of directive antenna, with the purpose of lowering the power consumption of your transmitter, while maintaining the same quality for your communication and the same interference for your neighbors.
The law says that I can maintain quality and decrease interference, but I don't gain any real benefit because I'm only saving half a watt. So I'm not very motivated to do so. I'd prefer if it was legal to split the difference between increased signal quality and somewhat decreased interference.
> What you want to do, i.e. increase the interference for your neighbors, is the wrong thing to desire.
Where do you think I said that?
Edit:
> your neighbors would also
Here, I'll elaborate on a scenario.
Originally, me and my 6 neighbors are all transmitting omnidirectionally and causing 1 unit of interference to each other person. Everyone gets 6 units of interference.
I want to lower my transmit power but double my EIRP. I am entirely selfishly motivated, and just want a better signal to my devices. As a consequence I will now cause 2 units of interference to a single neighbor, and 0.1 units of interference to all other neighbors.
What happens when everyone thinks this way and does the same thing? Well now the neighborhood receives 2.5 units of interference on average instead of 6. Even with a bit of variance as devices move around, everyone is better off now. I love that my neighbors did the same thing I did.
This (and the parent) really sound super interesting to me, but I don't understand. Before I spend hours on Wikipedia reading about EIRP and phased array (and probably give up), is there a chance one of you could explain this briefly in words I may understand? :)
A phased array is capable of "beamforming", that is, sending an electromagnetic signal most strongly in a specific, programmable direction, as opposed to broadcasting the signal in many or all directions.
EIRP is a measure of the maximum power in any direction, so a phased array that transmits 1W only forward has the same EIRP as an omnidirectional antenna that transmits 1W forward, but also 1W backward, and up, and down, etc. Overall the omnidirectional antenna may transmit much more power total, but still only 1W in any particular direction.
EIRP adjusts the total radiated power for the antenna gain.
So if you're transmitting 1 W and your antenna has a gain of 30 dBi (1000x), that's equivalent (from the perspective of whatever it's pointed at) to an isotropic antenna (no gain) emitting 1000 W at the same distance.
It should be obvious that EIRP is what matters for interference and human safety, hence why the FCC regulates EIRP instead of power output.
edit: GrantMoyer's answer is better.
A phased array is a very high-tech method of selective transmission so that you can send a radio signal that is stronger in one specific direction. The way I think of it is that it creates a virtual directional antenna where the direction is adjustable without actually physically moving the antenna elements. The actual tech involved is pretty heavy math and physics (and I don't fully understand it myself) so if you want to really understand it then you may still need to spend hours reading about it.
In the simplest possible terms, EIRP is the equivalent of power density. It takes into account how narrow the beam from your antenna is.
Wondering if this will spur innovators' handoff-based mesh networks (slow, low-bandwidth but very, very democratic).
When whitespace in television bands went unlicensed i don't know how much of that we saw: https://www.fcc.gov/general/white-space
I feel like the barrier may be whether dedicated hardware is required or not. In such a large band, 6 GHz, I would expect a lot of generalized (i.e. non-dedicated) platform hardware to be developed & offered allowing software-focused innovators to offer into the long tail of applications, including mesh network(s).
Everyone I've talked to from the LORA crowd and even some (LORA) alliance guys tells me lo-energy meshes are hard to get right. Am I missing something?
The new DECT NR+, the first non-cellular 5G standard supports mesh configuration but fixed not mobile network:
DECT NR+: A technical dive into non-cellular 5G:
https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/pos...
I wonder if ESP-NOW[0] would be useful for this. I've been toying with building some mesh-based lighting controllers for synchronizing lights. Fortunately it can be entirely static (number of nodes) which makes it an easier problem than dynamic meshes.
0: https://www.espressif.com/en/solutions/low-power-solutions/e...
Mesh networks are a neat idea, but the reality of is often disappointing e.g. given compatible radios all the IoT devices in a room could form a mesh network of equal peers, but if a few lightbulbs use their position (mains powered, good location) to form a hierarchical network it will actually work (without wasting battery power and air time).
This feels very pie in the sky and dreamlike. Of course some corp will figure out something to do within this space and make closed products that push out free and open uses. At least that's my pessimistic view opposed to your optimism.
If you pop open a spectrum analyzer in most places, you'll see a ghost town in the Cathedral and a hopping lively Bazaar in 2.4/5GHz. On net, it is good that more resources are going to the Bazaar.
That's a Bazaar I would love to window-shop in - and heck maybe purchase a couple of ornate unique carpets while I'm at it =)
6ghz is pretty fragile -- i can't imagine one product "pushing out" another when a wall will block the signal. Just don't have the closed products in your home, and the open ones should work just fine...
> The Commission envisioned that body-worn devices would make-up most VLP device use cases and that these devices would provide large quantities of data in real-time. Entities that support the Commission permitting VLP device operation expect that these devices will support portable use cases, such as wearable peripherals (e.g., smartphones, glasses, watches, and earphones), including augmented reality/virtual reality and other personal-area-network applications, as well as in-vehicle applications (e.g., dashboard displays).
i was expecting vehicle-to-vehicle communications
You could just put your mobile number on your back window to encourage conversations.
Getting a burner number is expensive though
There's IEEE 1609 series of standards. I haven't looked at it since 2009, so no clue how actively used/deployed that is though.
Do folks know if this increases the number of channels available for Wi-Fi 6e over 6GHz in the US, or does that require additional process?
Looks like it does not allow new channels for 6 GHz Wi-Fi. 802.11be (Wi-Fi 7) already covers full range of FCC's allowed frequency range. IEEE committee may add new channels in 802.11bn (expected to be ratified around 2028, and commercial name will be Wi-Fi 8) but it also looks like a low probably, considering both 802.11ax (Wi-Fi 6/ Wi-Fi 6e) and 802.11be (Wi-Fi 7) mostly focuses on reducing the interference between different networks by reducing the collision, instead of widening the spectrum (BSS coloring, Flexible Channel Utilization etc.)
> 1,200 megahertz of the 6 GHz band
Spectrum allocation is very weird.
Given the fragility of signals at these frequencies, how useful is this?
By that I mean that they're easily blocked, diffracted, whatever.
Fragility is a benefit; it reduces interference. This could be used for wireless VR goggles, for example.
The alleged/misunderstood "fragility" can be exploited though. A lot of residential walls are gypsum board, which contains a lot of water, and attenuates microwave signals.
Rather than fight this by trying to shout as loud as you can from a single AP across the house, you can put smaller, weaker APs in multiple rooms. Because of the excellent open air penetration and high frequency, you can get a multi-gig links with no interference or competition.
Can you get that down to low latency? Say less than 1ms for the hops?
No, at least not with current stack. Each hop adds big overhead
As long as the signal can make it all the way from a phone in my pocket to earphones or glasses on my head it's useful.
Not much different than 5Ghz which is heavily used currently.
6ghz isn't very fragile, 60ghz is
60ghz is isn't very fragile, 600 ghz is
You kids get off my submillimetre lawn.
600ghz isn’t very fragile at 50db, 6THz is! (6THz if a common wavelength for fiber)
6THz isn't very fragile at gigawatt levels in a tight beam path. Travels right through most objects (eventually)
“Can you hear me now? Goo— oh, wait a sec… How ‘bout now? Good!”
Wasn't this already done for Wi-fi 6e? We have commercial routers already supporting 6GHz channels
Can someone translate this into maximum usable range please
It's line of sight only. Think about it like a flashlight. If you have a flashlight (w/power) up on top of a skyscraper roof or a mountainside it can be seen at very long distances. At street level it goes till the next small rise in the ground.
Range for the newly-available parts of the 6 GHz band will not be substantially different from range for the 5 GHz band and the portions of the 6 GHz band that were already available for uses like WiFi.
Except C band, which could be huge depending on the ERP limits. =3
I think you're confusing this with the 60 GHz band (WiGig)
In general, its good for:
* indoor unobstructed environments
* outdoor point-to-point line-of-sight
It is a holiday miracle for small low power handheld devices.
We'll need to know the ERP limits for these bands before designing any changes.
However, hypothetically even 5W to 8W could open space networks (C band)
Neat. So with let’s say, neighborhood repeaters, you could potentially get pretty far with this, I guess.
> It is a holiday miracle for small low power handheld devices.
Is it really? Isn't the signal blocked if a person simply walks between he devices? i.e. if you are wearing a receiver and just turn around you will lose connection.
It would be wonderful if we could increase Bluetooth bandwidth by switching to this new spectrum.
I think that is exactly what they are going for.
Was this band used for anything else previously?
I hope other jurisdictions follow suit so hardware using it can be cheaper due to economies of scale. The segmentation of LoRA radios between US/EU is already pretty annoying and they're fairly niche.
Satellite communications, point-to-point microwave systems, and other similar things (high-data-rate, point-to-point communication) all operate near this band. However, there's plenty of spectrum and the use cases may be declining. There were also some radar systems in this band, but IIRC the useful new radar systems are higher-frequency (10's of GHz for resolution) or lower-frequency (10's-100's of MHz to have longer range).
From the press release:
> expand very low power device operations across all 1,200 megahertz of the 6 GHz band alongside other unlicensed and Wi-Fi-enabled devices.
Unless I am missing something, this means Wifi6 currently operates in this range.
Does this mean Unifi will sell outdoor WiFi 7 APs with 6Ghz transceivers?
It specifically says this is not for use with fixed wireless infrastructure, so no.
I like how they list their Twitter account
[shaky conspiratorial theory]
I wonder if this was in motion for a while and then intentionally accelerated to ensure it happens under Biden.
Optically it's a pretty pure win. Open stuff sounds good. Less regs sounds good. Tech sounds good. And it's not something that has a corresponding voting block opposing. Just pure upside politically.
Either party would love that.
Yes good conspiracy, vote for trump or biden. Nothing about personal data or tracking.
Is there any merit to non-ionizing frequencies having harmful impacts on human biological function, I thought so, but is it all "conspiracy" and laughed out of the room or a legitimate scientific part of these discussions?
I'm not a physicist or biologist but what's always made sense to me is that anytime you walk outside during the day you are bathed in broad spectrum radiation from the sun. So anything weaker than the sun is probably safe enough. Anything a million or billion times weaker is probably a million or billion times safer. We already know when and how radios get dangerous (large transmission towers, microwave ovens, etc) and how to mitigate that danger. Inverse cube law and somesuch.
The sun is damaging because it contains ionizing radiation (radiation that is powerful enough to directly disassociate a molecule into ions). This is the UV portion of sunlight.
UV starts at 800,000 GHz.
The 6Ghz being discussed here is completely non-ionizing, not even comparable to UV.
The only concern with 6Ghz is that is can also cause dielectric heating, which is the same as a microwave. But again, at 25mW, you can't even feel the heat from direct contact with the antenna, let alone a few meters away. Your exposure follows the inverse-square law [1], which means that it drops proportional to the square of the distance. So if it's not a problem at 10cm, it's 100x less of a non-problem at 1m.
[1] https://en.wikipedia.org/wiki/Inverse-square_law
evolutionary argument is humans are aligned with broad spectrum radiation from the sun, but not the artificial forms which have different magnitudes in different frequencies.
Eg: you are much less likely to get sunburn if you get plenty of natural (or artificial) infrared.
There is no such thing as artificial forms of RF. They're all wiggling photons.
If nature gave us a flute, and man discovered how to make a bass guitar, all though they sound different the only real difference is that the bass guitar is wiggling air molecules more slowly than a flute would. There is zero, nil, no distinction whatsoever between a "natural" and "synthetic" photon wiggling at a given frequency.
> you are much less likely to get sunburn if you get plenty of natural (or artificial) infrared.
I'm gonna need to see a source for that.
Microwave frequencies can harm biological function through heating tissue; in particular eyeballs have lots of water and poor ability to dissipate heat. However, very low power densities are almost certainly safe.
[edit]
Another example of non-ionizing radiation harming human tissue would be if you stick your hand in front of a cutting laser. Maybe obvious, but you asked...
Most concerns focus around the electromagnetic radiation heating your tissue. Microwave ovens operate at 2.4MHz, and most common frequencies can work like a microwave with varying efficiency. At the intensities of normal transmissions that isn't really a concern. For a time this seemed like something we might worry about with phones, since during a phone call there we have an active antenna right next to your fairly sensitive brain that might not like being heated up. But even there it turned out that the effect was too small to be of concern
Ham radio operators do need to worry about radio exposure safety for heating. But we are using much higher powers, 100W is normal HF radio, and 1500W is the limit. 5W handheld next to head is safe. Also, the
25mW is nothing.
Is there any theorizing or research being done around potential non-heating harmful effects of non-ionizing radiation?
Not directly, because there's no plausible hypothesis by which it could cause any biological effects whatsoever.
There’s none other than localized heating effects, and yes, it’s laughed out of the room.
So, obviously you don’t want to microwave your eyeballs, but you’d feel that in other nearby tissues as heat. If you don’t feel heat from a non-ionizing RF source, you’re not getting cooked. In any case, the amount of infrared coming off an incandescent lightbulb is about 3 orders of magnitude higher than the energy coming off a WiFi router antenna. If being in the room with a lightbulb is safe, so is being in the room with WiFi.
There isn’t a set of rules of physics where low-power, non-heating, non-ionizing RF is dangerous, and also where CPUs work. They’re incompatible. You can’t have both of those at the same time.
There's merit. Just to complex to understand and unpleasant to realize.
Eg of research indicating we should at least do more deep research before calling it "Safe": https://pmc.ncbi.nlm.nih.gov/articles/PMC9189734/
We honestly don’t know. Current safety standards mostly focus on preventing tissue heating, because that’s the one effect we can reliably measure and understand. But there’s a chunk of exploratory research out there looking at potential “non-thermal” effects—things like subtle shifts in cell signaling, membrane permeability, or oxidative stress—that might not show up as a measurable temperature increase.
So far, the studies that have been well-designed and replicated haven’t consistently nailed down a clear causal link between non-thermal EMF exposure (within the limits that regulators consider safe) and actual health problems. Still, some researchers argue that we’re not accounting for all the slow-burn, cumulative effects that might be happening. It’s not easy to tease out these subtle influences from the noise of environmental variables, and that makes it hard to really say we’ve got a handle on the whole picture. Check out Prof Michael Levin's Bioelectricity work if you want to go down a very interesting rabbit hole about what we're only recently discovering about how our biology might really work and how electricity and emf's shape it.
Well the microwave oven is an example of non-ionising frequencies having harmful impacts on human biological function.
With a large enough antenna and enough power you can cook your neighbor.
The ham radio licensing procedure in the US mostly focuses on this effect. Even though there's nothing conclusive I'd imagine there are other deleterious effects that aren't trivially measurable. If it can heat it up it can do other stuff too. Cooking your brain by standing too close to a high power transmission tower can't be good.
I'm an amateur extra, I would challenge any "scientist" laughing EMF dangers off to go find the nearest AM radio tower and spend 6 months in the transmission room for "science".
Without sarcasm, the studies I have found over the years ruled out cumulative effects (unlike ionizing radiation). They so far haven't been able to rule out various types of cancer, ALS, or other diseases caused by long-term exposure.
Url changed from https://www.fcc.gov/document/fcc-opens-entire-6-ghz-band-ver..., which points to this.