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Building on this, although frequency allocation charts are aesthetically pleasing, they are cumbersome to use for research or determining what frequencies are allocated to what services. In practice, simple table formatting provides the easiest way look at allocations and compare country by country.
One main reason is that allocations are accompanied by footnotes that provide further clarification for how each frequency band can or should be used. For instance, footnote US334 states that the in the bands 17.8 GHz to 20.2 GHz, fixed-satellite services transmitting from space to earth via geostationary and non-geostationary satellites may be authorized on a primary basis. For people/companies looking to provide services, this is the difference between being able to operate in a band and not.
Additionally, it’s simply much more practical to look through and filter a table of allocations. As an example, this very simple site allows for easy comparison’s between the allocation tables of 25+ countries: https://spectrumdatabase.io/. It’s not as pretty, but it’s more practical.
Either way, it’s great to see people interested in frequency allocations!
..but it doesn't even have the US?
the US isn't the only country! (but it should have the US, and others; EU country representation is also thin)
Another fun, somewhat related poster from 1944: Chart of Electromagnetic Radiations [0], and a "color-corrected" version [1].
[0]: https://www.flickr.com/photos/llnl/9403051123
[1]: https://www.flickr.com/photos/acme-laboratories/31849902131
There's also this: http://unihedron.com/projects/spectrum/downloads/spectrum_20...
I love that poster! Especially because it’s generated from LaTeX and open source: https://github.com/unihedron/spectrum
> "color-corrected" version
Not only it clips some colors for no reason (look at the blue background around "broadcasting radio" house -- the gradient transition is totally gone. I assume the editor just used lasso tool to select "white-ish" parts and replace them entirely with a single color, instead of using color level?), it didn't even correct the background to pure white (but some reddish color)? Ugh!
Oh my, those charts are so beautiful. Thank you for sharing.
I love this chart and would like to print it. Can anyone gauge if this is still somewhat current or if there's a better one?
It is copyright 1944. So it rather charmingly hand-waves away frequencies above 10 MHz or so. Such frequencies will be useful for television! And the plot stops at 100 MHz. (Nearly all radio used today is above 100 MHz.)
That said, much does still hold true. Longwave is still used by giant shore installations to communicate with ships. (Mostly by coincidence. Long wavelengths can reach submerged submarines.) The aeronautic band is still used by aeronautic non-directional beacons. The AM broadcast band is still AM broadcast. Some of the amateur bands are still in the same place today.
The physics and electronics depicted seem accurate. Its creators were clearly informed of the cutting edge in the 1940s; it depicts a magnetron, which had been invented about a decade before, and not widely used until high-power models were developed and then applied to radar c. 1940. A section about the health effects of ionizing radiation is conspicuously absent to my modern eye.
Those are beautiful. Where can I find more charts like these?
ooh this is neat. is there a Canadian version like this that anyone knows of?
I hadn't seen one of those in a while. It's now full all the way up to 300GHz. The last time I saw that chart, there was little if anything above 100Ghz.
Terahertz, here we come![1]
Incidentally, radio regulation, by international agreement, ends at 3 THz. Above that, it's called "light".
[1] https://docs.fcc.gov/public/attachments/DOC-356588A1.pdf
> radio regulation, by international agreement, ends at 3 THz. Above that, it's called "light".
That's true, but it's also tautological.
If you gave an intelligent but blind alien the task of describing our international radio regulation they'd probably put the visible signal lights on airplanes and ships under the same umbrella as WiFi or FM radio.
In reality visible light is also highly regulated, and in much the same way as the radio spectrum.
An old lab I worked in had a malfunctioning RF power supply for a vacuum plasma generator.
None of the researchers were cognizant of the fact it was spewing noise outside its frequency allocation until some relevant government agencies quickly visited and had it shut down. We were impressed with the response time :)
The FCC used to have specialty cars with spectrum analyzers and complex directional antennas built into the roof to quickly triangulate rogue signals.
Not sure if that's still done these days but I'm sure with GPS receivers and a couple mobile units, a position could be pinpointed very quickly.
How far off from its allotted frequency does a device have to be in order to interfere? We are all aware of tuning an old radio where a station (e.g. broadcasting an FM signal) will come in slightly at 102.3 but much clearer at its real value at 102.4 so there is some range for each station.
Does the range change as frequencies increase (i.e. does the margin of error get smaller as you go up the spectrum)?
Question for the audience: which parts of these allocations are actually fiat decisions made by each country; which parts are actually global decisions (where as soon as someone starts using it for X, every other country is stuck with that band being polluted with X, so they may as well use it for X as well); and which parts aren't decisions at all, but are just "the only possible frequency-band that kind of thing would work well on"?
Global decisions are made by treaty, through a United Nations organization known as the ITU.
Some allocations are harmonized globally. Others are divided up into one of three global regions - roughly the Americas, Europe/Africa, and Asia/Oceania. Then these are further divided into one of 90 zones that roughly follow country-specific boundaries.
All of this is decided very bureaucratically. In some cases decisions are constrained by the laws of physics (HF signals are going to bounce across the globe), in other cases by practical necessity (aviation/maritime allocations are harmonized to facilitate global movement of vessels, satellites are going to orbit across the globe). However, in some cases allocations will differ between ITU regions or zones (especially local broadcast and land-mobile communications users).
Further, priority is usually given on a first-come/first-served basis, but harmonization is encouraged. Individual countries can modify their local allocations, provided this don't interfere with other global users.
You can view the global allocations by looking up the ITU Radio Regulations, Article 5. (PDF here: https://www.itu.int/pub/R-REG-RR-2020)
If you're curious about the process behind all this, look up the World Radiocommunication Conference, which is held every ~3 years: https://en.wikipedia.org/wiki/World_Radiocommunication_Confe...
The amount afforded to corporations vs unlicensed or amateur use gives you a good picture of how the power dynamics work in our “democracy” https://scholar.princeton.edu/sites/default/files/mgilens/fi...
Most of the allocations seem quite reasonable, eg lots of navigation, radio astronomy, etc, which don’t seem particularly corporate to me. I guess TV is corporate but there are a lot more people who watch rev than listen to amateur radio. Similarly people get pressure good use out of mobile phones. Plausibly it would be good if more of the spectrum was available for Wi-Fi.
I guess one question is: are there amateur/unlicensed uses that are starved of bandwidth (Wi-Fi does strike me as something that fits but is there anything else)?
If you have some sort of example of amateur or unlicensed spectrum that is more starved for bandwidth than the mobile phones that 300m Americans spend an average of 5hrs a day using, I’d love to hear your ideas.
In practice do we need more reserved/unallocated bands? The problem with unlicensed bands is interference and the like - they can't be used together without stomping eachother (eg. in FPV RC, analog and digital transmitters have difficulties because digital stomps the analog signals).
Arguably given the above it would be useful to have a larger range of frequencies available to amateur/unregulated users, but it's also probably true that the general public gets more utility from more 4G LTE spectrum, if we're honest.
See also IP address allocation and DNS (TLD) allocation.
Hierarchy is something like:
1. US military/intelligence
2. Transnational corporations
3. Other large orgs/governments
(distant) 4. People
You can operate in any frequency so long as you are in a faraday cage :)
I'm currently going through a bit of a transit map obsession, and these frequency allocation charts just feel like they tickle the same feeling. The way it codes information densely, into simple colors, in easily understood ways. Even the part where it distorts things slightly in order to depict them cleanly echos the way subway and metro maps often fudge geographical features to make their maps more readable. I wonder if there's anything one of these diagrams can copy from the other. Maybe the radio spectrum would make more sense if organized into "lines" of some sort
I have the same obsession, I think. Do you know of any place that sells high quality printed maps or charts, with (for lack of a better word) "engineering" data? I'm particularly interested in energy, transit, or natural resource maps and charts. Or even just a collection of nice looking, info-dense charts.
Czechia has this really cool website that lets you identify what every frequency band is used for in depth [0]; it seems to be run by a telecom so I'm presuming its fairly correct and up-to-date.
I don't know if there's something like that for the United States.
I was searching for this just last night, thanks!
Though ideally an interactive one, with zoom and some capacity for search and for personal annotation.
I don't know what to make of the bands that they show. e.g. in the USA, garage door openers listen in the 300-390MHz range (depending on brand), but per the chart these are blocked off as "Federal-Exclusive" bands and detailed as for FIXED or MOBILE use (with a band for AERONAUTICAL RADIONAVIGATION in the middle).
As a garage door opener owner/operator isn't licensed, it woudn't qualify as FIXED (though the transmitter wouldn't be fixed in all cases) and it certainly wouldn't qualify as "Federal-Exclusive."
(They're not in the ISM spectrum [0].)
[0]: https://en.wikipedia.org/wiki/ISM_radio_band#Frequency_alloc...
Many of those devices are operating under the FCC's Part 15 rules for unlicensed transmitters, which allows them to use certain bands provided that they stay below a minimum power level (or use an inefficient antenna) and don't cause interference to licensed users.
The idea is that by keeping the radiated field sufficiently weak, you avoid long-distance propagation and won't interfere with anything not in your immediate vicinity.
This is why your garage door opener only works when you're right next to your house. (Compare with a licensed mobile radio, which will easily transmit 100-300 miles given a clear line of sight.)
This chart doesn't show all of the frequency allocations. It's mostly showing who has priority on said frequency and who has secondary rights to not interfere with the frequency priority.
There's a third "level" (you can look it up on the FCC's website if you like) that includes things that have low priority (any of the items listed in the chart above supersede them) and are normally low enough power that they will not cause any interference to the primary or secondary frequency holders in the chart. This is why you don't see things like wifi or garage door openers in the chart, but they are part of the band plan, usually under "RF Devices" which falls under Part 15 of the FCC's Code of Regulations.
"The European table of frequency allocations and applications in the frequency range 8.3 kHz to 3000 GHz."
https://docdb.cept.org/document/593
[PDF] - https://docdb.cept.org/download/4162
[Excel] - https://docdb.cept.org/download/4089
How do you find the regions wifi uses on this chart? I can't really find any correlation even knowing the frequencies. Or is that somehow not in scope?
Wifi is not on the chart. The chart is based on the "FCC ONLINE TABLE OF FREQUENCY ALLOCATIONS". [1] That table has 3 columns of data, the first two columns are what you see in the chart above. The third column is where the wifi frequencies are defined (among some others), listed as "RF Devices (15)" since wifi falls under Part 15 of the FCC Code of Regulations. [2]
[1] https://www.fcc.gov/engineering-technology/policy-and-rules-...
[2] https://www.ecfr.gov/current/title-47/chapter-I/subchapter-A...
2.4GHz and some 5GHz WiFi is in the ISM (industrial, scientific, and medical) bands. The 5.8GHz ISM band isn’t marked on the chart for some reason. Perhaps the little teal-colored rectangles in the middle of the 5.2-5.8GHz region are WiFi.
I believe they fall under the "amateur" bands. I.e. frequencies not requiring a license to utilize (given you obey given power limits). That's why the same frequencies are shared by WiFi, Bluetooth, ZigBee, etc.
Some of the amateur bands also overlap with allocations for things like radar. For example, a subset of the "5Ghz" WiFi channels (the "DFS" channels) can only be used if the access point will auto switch to a different channel upon detecting a radar pulse.
Back in the early 00s, the “Digital Promise” org sought to set aside some spectral “land” to support digital education, just as the western reserve set aside land for public education. I thought it was a brilliant idea.
Meanwhile, in the late 00s,federal agencies were selling their emergency spectrum allocations to the highest bidder (and apparently still are as of 2021)
https://www.ntia.doc.gov/files/ntia/publications/fifth_annua...
Before clicking, I thought it was going to look like the IP allocation charts (or Colorado River water rights), with some areas fighting for crumbs and other older stakeholders massively overprovisioned, but this actually looks quite reasonable to me.
I just got this in poster form (surprisingly cheap) and love having it up on the wall
Any tips for putting it on the wall in a relatively neat fashion? I want to hang more stuff on my walls in general, but I care about appearance.
This crazy, beautiful chart illustrates the incredible complexity of managing one of our nation’s most crucial – and invisible – national assets: the radio spectrum.
I would love to know if there's a $ per spectrum bandwidth overlay that can be made on this chart and if there are any interesting observations from that?
What does “FIXED” mean on these charts?
The transmitter is at a fixed location, like a radio tower or satellite uplink antenna
That’s a holiday sweater. Not a well-designed. Which is why it looks nice. Very human.