Talk:List of WLAN channels

message: I'm adding this because this information is missing from wikipedia. 802.11a channel/frequency mapping is difficult to find and I expected to find it from Wikipedia. Information on channel/frequency mappings should be readily available. I'm hoping this article will find a better place or name, but still exist in wikipedia, preferably 802.11a/b/g/n channels all on one page. --Joneskoo 16:45, 22 September 2007 (UTC)
replies: text: IEEE 802.11-2012 § 18.3.8.4.2 provides that reference.J0boyers (talk) 05:28, 5 January 2013 (UTC)
thread_title: Reason for page

message: Haven't the channel restrictions in France been removed in the meantime?
212.213.204.99 05:18, 2 November 2007 (UTC)
replies: text: Find a verifiable source and change the text in the article. -- KelleyCook (talk) 20:51, 3 January 2008 (UTC)
replies: text: Done - 82.123.102.83 (talk) 17:10, 13 March 2008 (UTC)
thread_title: France

message: Maybe add Israel to the first table (channels 3-9)? 87.194.223.183 00:51, 4 December 2007 (UTC)
replies: text: Give a definitive source (either a link to the Israeli law or an IEEE citation) and then it can go in. -- KelleyCook (talk) 22:04, 4 December 2007 (UTC)

text: admin 103.10.66.13 (talk) 12:06, 1 December 2023 (UTC)
thread_title: Israel

message: Please be careful regarding assertions of legally approved channels... (in the first section) References to 802.11 standards do not help much (not even 802.11-2007) as even this document is actually about three years old since I and 300+ other 802.11 members wrote it. Regulators (esp Japan and a couple of EU countries) have made changes to the channels in the last three years. To be crystal clear referencing 802.11 is not proper as it is not a regulatory organizarion and it lacks any legal authority to set channels. 802.11 merely reports what the status is at the time of the standards draft which is three or more years earlier them the date... I tried to make updates but now it appears that I am blocked and I do not want to refer to myself as an authority reveling who i am, less the regulatory rnvironmrnt change and litigation happen do to the section not being updated...  —Preceding unsigned comment added by 76.118.191.206 (talk) 03:48, 2 January 2008 (UTC)
replies: text: You're changes are not being blocked.  The message I left on your talk page simply was stating that Wikipedia demands verifiable sources.  I realize that by its very nature of being a multiple committee driven multi-year process, the IEEE 802.11-2007 information is out-of-date.  It would be more than welcome to have newer and correct information.  But any changes that you add needs to be verifiable, such as was included with the recent change to the Japan 5Ghz section.  A secondary problem is that you can't put a blanket "This is Wrong information" statement, even if it is true, as it both has a NPOV stance and breaks the Wikipedia:No disclaimers in articles policy.  The article already states three times that "These regulations are subject to change at any time." Let me make try and compromise by make that more topical -- KelleyCook (talk) 20:51, 3 January 2008 (UTC)

text: 76.118.191.206 145.224.73.53 (talk) 22:00, 20 October 2023 (UTC)
thread_title:  Wrong information 

message: Asia is not a regulatory domain!? Find me a country on this planet called "Asia" please remove it  —Preceding unsigned comment added by 76.118.191.206 (talk) 18:28, 3 January 2008 (UTC)
replies: text: Gone, next time please WP:Be bold -- KelleyCook (talk) 21:01, 3 January 2008 (UTC)
thread_title: Asia

message: According to http://www.fcc.gov/oet/info/rules/part15/part15-9-20-07.pdf page 130 the bands 5.15-5.25 are available for unlicensed use at 50mW, 5.25-5.35 and 5.47-5.725 at 250mW and 5.725-5.825 at 1W.  Is there another reason channels 52-64 are listed as No for the US? (I'm no expert in RF so not editing the article) — Preceding unsigned comment added by 131.216.7.132 (talk) 23:02, 24 March 2008 (UTC)
replies: text: Thanks for reporting this, I've now submitted a patch for this addition. -bkil (talk) 22:45, 3 December 2020 (UTC)
thread_title: 5GHz Channels in the US

message: Spain, like the rest of Europe, allows channels 1-13 (instead of 10-11). I have found some places where it says it is only channel 10 and 11, and I don't know why.
According to note UN-85 in CNAF (spanish legal frequency table) you can use 2400-2483,5 MHz for indoor wireless data networks (100 mW EIRP).
http://es.wikipedia.org/wiki/CNAF
http://www.mityc.es/Telecomunicaciones/Secciones/Espectro/cnaf/
Moreover, any modern wifi equipment legally sold in Spain supports channels 1-13.  —Preceding unsigned comment added by LatinSuD (talk • contribs) 15:56, 2 May 2008 (UTC)
replies: text: I took out the two columns which someone edited back to the (out of date) 802.11 doco.  Thanks for the reference. -- ~~ — Preceding unsigned comment added by GregGarner (talk • contribs) 19:36, 22 September 2009 (UTC)
thread_title:  Spain has more channels 

message: The '2.4 GHz (802.11b/g/n)' section mentions 25 MHz of channel separation, and the picture shows 22 MHz per channel bandwidth usage. However, the n version of the standard (802.11n) talks about 40 MHz of bandwidth. Should this be clarified here? Tim-mnm (talk) 14:51, 16 October 2009 (UTC)
replies: text: According to IEEE 802.11n-2009 40 MHz is for double channel mode within 802.11n (max. 600 Mbit/s instead of 288.90). Concerning the 22/25 MHz bandwith per channel both numbers make sense: With 25 MHz one could use channel 1, 6 and 11 without overlap and with 22 MHz for each channel even four channels (1, 6, 11 and 14 – the boundary between 11 and 14 would be exactly 2473 MHz) should be usable without overlap. --Frequencyhopper (talk) 14:55, 23 December 2009 (UTC)
replies: text: 802.11b ist outdated since long, simply use the same modulation-modes as on 5GHz and also the same channel-spacing. That means you can use wifi-channel 1,5,9,13 (keep in mind that in the USA channel 13 has some limitations). Keep it clean for the User, do NOT name the 40MHZ-Channels by mid-frequency, name them by 20MHz fallback-channel. So tell the user to select channel 1 or channel 13 for 40MHz bandwidth on 2.4GHz wifi. In the USA you might tell them to use channel 1 or 9, if they do not jet have hardware that is legal on wifi-channel 13. --DG8FZ  16:26, 27 July 2015 (UTC)
thread_title:  22, 25 or 40 MHz bandwidth? 

message: Is it true that the use of channel 14 is restricted or even prohibited in most countries of the world mainly because it conflicts with the satellite phone services operated by Globalstar and Iridium which use the frequency range from 2483.5 MHz to 2500 MHz? --Frequencyhopper (talk) 22:13, 22 December 2009 (UTC)
thread_title:  Channel 14 

message: FCC 15.407 covers channels within 5.15-5.25GHz, 5.47-5.725GHz and 5.725-5.825GHz bands. Since the center frequency of channel 165 is at 5.825GHz, then part of the channel's spectrum will go outside the 5.825GHz band edge. I don't think channel 165 can be covered by FCC 15.407 [12]. The FCC 15.247 [8] rules include channels in band 5725-5850MHz. The channel #165 which spans from 5815MHz-5835Mhz is allowed in the US, but I think it should be covered by FCC 15.247 [8] instead of FCC 15.407 [12]. 5GHz (802.11a/h/j/n) table has reference to [12] in the header for United States. I think a reference to 15.247 [8] needs to be added to Channel 165. Comments?
On 2020-11-18, the FCC Adopted Report and Order FCC-20-164 which added 5.850-5.925 MHz to 47 CFR 15.401 for Wifi use https://www.fcc.gov/document/fcc-modernizes-59-ghz-band-improve-wi-fi-and-automotive-safety-0 Mrdvt92 (talk) 14:53, 3 December 2020 (UTC)
thread_title: 5GHz Channel 165 in the US

message: This is my first ever edit on wikipedia, so forgive me if this is not the procedure to request changes to documents. Basically I'd like to point out a fallacy in the assumption that non-overlapping channels in the 2,4GHz band are the ideal channels to obtain the maximum throughput. Non-overlapping channels make sense if the physical limit on the throughput is the thermal noise from concurrent transmissions.  For example I can have an RSSI of my desired signal -45dBm at the receiever and an interfering signal of -80dBm and so have an SINR of 35dB. As the 54Mbps mode needs an SNR of 21dB to be received this is ok from a thermal noise point of view
It should be noted that a CSMA-CA mechanism needs a definition of what it considers as an occupied channel, and this is defined by the "clear channel assessment" (CCA) function of the PHY layer. In 802.11bg the CCA is described as the following two steps
1.	Try to synchronize to an 802.11 preamble and if the synchronization occurs the channel is flagged as occupied. This effectively means that the channel is considered as occupied if a signal is received at the limit of the receiver sensitivity. For 802.11g that receiver sensitivity for the 6Mbps BPSK (as used in the preamble of the WiFi signal) mode is -85dBm. Note that as the instantaneous SINR requirements for reception of the 6Mbps mode is 6dB and for the 54Mbps 64QAM mode is 23dB, this CCA is very conservative and even very distant 802.11 devices can prevent communications between two 802.11g devices that are close and the actual interference of the distant device would be well under the SINR requirements. 802.11n has some optional "green-fields" preamble with a different CCA function that is suppose to address this, but I currently know of no manufacturer that has implemented these 802.11n exclusive preambles.
2.	If no signal is detected by step 1) perform an RMS power measurement and if the detected power is above the threshold (-65dBm defined in section 14.6.15.3 of IEEE 802.11-2007) signal that the channel is busy.
This two step process has some implications for WiFi frequency planning and in particular the myth that the best allocation is channels 1,6,11 only as common wisdom implies. As the CCA function itself limits the access to the channel rather than the SINR in most cases, using channels 1,6,11 only means that 2 APs that using the same channel are limited by a CCA threshold power of -85dBm, whereas for example if you could use the channels 1,2,7,8,13,14 instead then the distance between the same channel reuse might be 70% further and the CCA limitation on access to the channel between overlapping channels (like channels 1 and 2) is 20dB higher. In fact the best results, given the existing CCA function is to use all of the WiFi channel and maximize the distance first between identical channels, and second between overlapping channels.  — Preceding unsigned comment added by 163.116.6.11 (talk) 13:22, 16 October 2012 (UTC)
thread_title: The Myth of 1, 6, 11

message: The fundamental flaw in using the 4-channel scheme is that the non-overlapping distance requirement applies to both APs and clients. If you refer to Cisco's 2004 Whitepaperhttp://www.cisco.com/en/US/docs/wireless/technology/channel/deployment/guide/Channel.html several cases are presented where a client creates a CCA-Occpied condition on two or more APs using minimal-overlap channels even though the APs are physically separated past the point where the RMS of detected power is <-65dBm.
:Err.. but does this really way up against loosing a whole 20MHz channel? Also, how does this relate to the fixed channel scheme of 36, 40, 44, 48, etc. in the 5GHz band? Do you propose changing this scheme as well? I've been using the 1, 5, 9, 13 scheme for a while, and one advantage is that 4 channels allows for easier cell separation, kind of related to the 4 colour problem. Seriously, I think this needs more discussion and I strongly urge that it be switched back to 1, 5, 9, 13! —James Haigh (talk) 2013-11-17T02:41:46Z
::The article text "Leaving 3 or 4 channels clear between used channels is recommended to avoid interference.[4] The exact spacing required depends on the protocol and data rate selected as well as the electromagnetic environment where the equipment is used." already covers the consideration that different environments and use requirements may allow the use of a greater than 3 channel scheme.  In your worst-case scenario you will have only 3 non-overlapping channels.  Whether one can use 4 (or even more) channels with some overlap is dependent on better than worst-case scenarios.  — Preceding unsigned comment added by 192.55.20.36 (talk) 19:28, 5 December 2013 (UTC)
thread_title:  Rebuttal: The Flaw in the 4-Channel Minimal-Overlap Scheme for 2.4 GHz 

message: I've just been checking these channels. I believe the UK channels are dictated by IR2030 which specifies a band from 5500MHz to 5700MHz. I don't think there are any higher channels unless someone knows different?  — Preceding unsigned comment added by Edlong (talk • contribs) 10:27, 18 January 2013 (UTC)
thread_title: UK 5GHz Channels

message: The first link at the bottom of the article, for 802.11-2007, brings one to the IEEE site.  However, due to 802.11 having its latest conglomeration of updates and amendments published in May of 2012, it now goes to the proper 802.11-2012 standard document.  What would be the proper way of updating the article to reference the 2012 standard rather than the (now obsolete) 2007 standard?  Subclauses such as 19.4.2, which are referenced in the article, do not change, so that shouldn't be an issue.  However, it should reference the current standard.  This would be viewed as a significant change, so I figured I'd post here first.J0boyers (talk) 05:37, 5 January 2013 (UTC)
thread_title:  802.11-2012 Update 

message: The FCC is going to expand the 5 GHz band to a continuous block from 5.150 to 5.925. Ploxhoi (talk) 22:56, 4 February 2013 (UTC)
thread_title:  US 5 GHz Expansion 

message: 802.11-2007 Japan MIC Released the new 5 GHz band (W56). Bureau Veritas — ADT. Retrieved 2008-02-23. is broken! is there a way to get the information direct from http://www.soumu.go.jp/english/ Ministry of  Internal Affairs and Communication.  — Preceding unsigned comment added by 125.192.69.212 (talk) 03:34, 13 May 2014 (UTC)
thread_title:  Broken link. 

message: Is it realy a good idea to use just one 40MHz-channel (channel 3)? So the half of the band is not used. There is a second nonoverlapping one: 11. I know it interfers with channel 6 at 20Mhz. But I think it's more a reason not to use channel 6 (and may 5 instead). --Fabiwanne (talk) 08:19, 27 May 2014 (UTC)
thread_title:  2,4GHz: 40MHz channel 11  

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thread_title:  External links modified 

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thread_title:  External links modified 

message: What is DFS? That and a number of other abbreviations are not defined in the page - essential for an encyclopedia.  — Preceding unsigned comment added by 129.192.208.15 (talk) 03:23, 10 November 2016 (UTC)
replies: text: Channel allocation schemes#DFS --Voidvector (talk) 03:14, 5 December 2019 (UTC)
thread_title:  What is DFS? 

message: Most of the world might include europe, but in most of europe, the suggested non-overlapping channels are 1, 7 and 13. (or, 1, 3, 5, 7, 9, 11, 13 as half-overlapping channels)
2001:A62:1180:B4F1:88B2:ADCB:ADA9:EDDF (talk) 21:38, 29 January 2017 (UTC)
thread_title:  NonOverlappingChannels2.4GHzWLAN-en.svg 

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thread_title:  External links modified 

message: Dear editor. I have reverted your deletions, but you are free to explain why we would need to make the changes you have proposed. I have double checked the existing references and could not spot on error at first, but do correct me if you have additional references. bkil (talk) 17:10, 8 July 2018 (UTC)
thread_title:  Indoorness/availability of 5690–5730, 5710–5730, 5735–5815 

message: I quote the following note from the main article that I would like to discuss with you:
I have the following issues:
* I tried to review the current USA situation in more depth. Could someone please help me calculate the exact limits that we must obey? I tried to piece together the various rules, but I failed to come to the conclusion that transmission is allowed on 1-11 and only on those channels. See the below issues.
* I don't think that the Globalstar comment is relevant at the end - we aren't "operating" within 2483.5-2495MHz when we use 12 or 13, it's only a question of unwanted emissions escaping (I'll address this below). Maybe it's only relevant for channel 14.
* In reference 66 from 2016, comments 33-36 on page 17-18 deal with the question of "opening up" channel 12 and 13. They conclude with "No satisfactory mechanism allowing general use of Channels 12 and 13 in the 2473-2483.5 MHz spectrum without significant risk of interference to Globalstar’s licensed MSS operations has been proposed. Therefore, we decline to relax the restricted band requirements" Is Globalstar on this band still a thing, are there any follow ups about this question from the past few years?
* Commenting on the quote from reference 62: The center frequency channel 11 lies 21.5MHz away from the boundary 2483.5MHz. According to the 802.11b standard spectral mask, 21.5MHz deviation only calls for a power spectral density reduction of 30 dBr (>= 22MHz deviation is needed for 50dBr). So if we needed to obey this rule, only 1-10 would be specifically usable.
* From reference 64 47 CFR § 15.205 "only spurious emissions are permitted in any of the frequency bands listed below: [...] 2483.5-2500". According to §15.209, "the emissions from an intentional radiator shall not exceed the field strength levels specified in the following table:", limiting 2.4GHz band emissions to a maximum of 500 microvolts/meter at a measurement distance of 3 meters.
* The text in Wikipedia also mentions that low power emissinos may be possible on channel 12 and 13, but how low is this, 100mW, 10mW? Anyway, how common is this? Has anybody tried, measured and published anything about this? If this would be a thing, I think we should update wireless-regdb to this effect. If not, we should give a proper link and citation next to the prohibition.
* Considering the equation E = sqrt(30 * P) / r, 500uV/m in the restricted band allows a maximal power of about -41dBm there. As the 802.11 spectral masks only call for a maximum reduction of 50dBr, this couldn't theoretically be met on any of the channels at 1W transmit power. Considering real life systems, according to some spectrum analyzer screenshots I found, this is pretty hard to meet even for channel 11 - do note if you find anything that shows otherwise. On these screenshots it does show that common systems perform vastly better than what the spectral masks call for (much steeper), but they have a pretty long tail (meaning that after a few MHz, distance doesn't matter that much).
* Now if we assumed that routers contained special extra filtering for just above channel 11 (so it rolls off sufficiently before 2483.5MHz), wouldn't that greatly reduce performance on channel 11 and 12 if the device was used in other countries? Or perhaps could this filtering be switched by software (please show me the driver code that does this if yes)? If this extra filtering couldn't be switched, but it still wouldn't hamper channel 11 and 12 operation in other countries, doesn't that mean that if the device passed FCC conformance testing, then the filters could also do their magic in the USA as well?
* Also, if perhaps the signal shape of 802.11g/n transmissions occupy less bandwidth and roll off earlier, would it be perhaps more realistic to only ban 802.11b transmissions on channel 12/13?
--bkil (talk) 19:53, 3 September 2020 (UTC)
replies: text: The Linux kernel Wireless Regulatory Database (see link above) has been updated on 29 Apr 2020 to allow 30dBm (1 Watt) for the range 2400 - 2483.5MHz in the US. It is considered an authoritative source as it is incorporated into all linux-based Wi-Fi devices. It links to Federal Regulations §15.247 (b) 3, quote: "For systems using digital modulation in the 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz bands: 1 Watt." 89.139.221.165 (talk) 17:19, 30 September 2020 (UTC)

text: Upon further examination, it appears the linux kernel regulatory database is incorrect in allowing 1 Watt on channels 12-13. According to FCC decision from 2016 FCC-16-181A1.pdf, paragraph 36, quote: "No satisfactory mechanism allowing general use of Channels 12 and 13 in the 2473-2483.5 MHz spectrum without significant risk of interference to Globalstar’s licensed MSS operations has been proposed. Therefore, we decline to relax the restricted band requirements because unlicensed operators using channels 12 and 13 would not be able to coordinate with Globalstar to prevent interference with MSS operations above 2483.5 MHz. "  Is there any later FCC decision that supersedes this 2016 decision? 89.139.221.165 (talk) 12:01, 5 October 2020 (UTC)
thread_title:  Should the 2.4GHz channel 12 and 13 in the USA need updating? 

message: Linked from this wi-fi.org page, I found that the EU has adopted the lower end of the 6 GHz range. Can someone update the article accordingly? -- 2A00:23C7:8913:6101:D4AD:679D:4117:BDE2 (talk) 18:52, 9 October 2021 (UTC)
thread_title:  6 GHz adopted in European Union 

message: via 197.156.77.136 (talk) 17:38, 8 January 2022 (UTC)
thread_title:  dara 

message: Many routers use the 802.11ax protocol on their 2.4GHz and 5GHz bands. Many incorrect references using this misinformation are present in this article.
Please correct this misinformation. 802.11ax is not related the 6GHz only.142.113.109.188 (talk) 12:31, 24 June 2022 (UTC)
thread_title:  802.11ax is not a frequency but rather a protocol 

message: Como saco la contraseña del wifi ? 186.12.28.54 (talk) 13:03, 25 July 2022 (UTC)
replies: text: Jonatan 181.9.187.85 (talk) 11:25, 18 April 2024 (UTC)
thread_title:  Hola 

message: Depiction of a Wi-Fi network in infrastructure mode. The device sends information wirelessly to another device, both connected to the local network, to print a document. 134.35.253.201 (talk) 18:09, 23 August 2023 (UTC)
thread_title:  (untitled section by anonymous user) 

message: Request for Feedback
An update on  created a new table spanning 5855~5990 MHz within the section titled "5.9 GHz (802.11p)".
This new table overlaps and conflicts with the tables in both the 5 GHz and 6 GHz sections, by spanning 5855~5895 MHz and 5935~5990 MHz respectively.
I am concerned about the accuracy and currency of the material inserted by this update.
It lacks citations, other than the 802.11p article, and appears to have even misinterpreted that source. For example, it says "No" for the section where the US removed the restriction on the bottom 45 MHz of this band, meaning it went from being available only to licensed users, to effectively being an extension of the existing "5 GHz" unlicensed band. Moreover, this unlicensed access was already shown in the table in the 5 GHz section.
Although 802.11p is based on WiFi, it differs in some technical as well as legal aspects. It's the technology underpinning V2X and WAVE which are licensed uses of the spectrum, and not available to consumer-grade WiFi devices at all.
Even if the rest of the information was accurate (which I now doubt), it is questionable whether this section as a whole is relevant to this article: although it's not explicitly stated, the rest of this article is about use of the radio spectrum by unlicensed WiFi devices; as far as such devices are concerned, the portions marked in green in this table are not usable.
Depending on how you view the overall focus of the article, this is either misleading, or outright wrong.
Accordingly, I propose to:
# remove the table, after inserting any relevant portions into the existing 5 GHz and 6 GHz tables.
#* At this point I suspect there is no salvageable information, but I would appreciate feedback on this.
# remove "5.9 GHz" from the section title, leaving just "802.11p", and demoted it to a sub-heading within the 5 GHz section. Amend the following text to highlight that licensed spectrum use is outside the scope of this article. The only relevant point is that this block has been halved in size, thus expanding the 
# add a note to the article preamble to point out that it's about unlicensed spectrum use
Martin Kealey (talk) 12:30, 28 November 2023 (UTC)
thread_title:  Tabulation of 5.9 GHz in 802.11p 

message: First problem: in the "6 GHz" section, the channel centred on 5935 MHz is labelled as "2", while the channel centred on 5945 MHz is labelled as "1". Is this anomalous ordering real, or a wiki editing error at some point?
Second problem: in the "5.9GHz (809.11p)" section, the same channel centred on 5935 MHz is labelled as "187". This follows the logical numbering of channels starting with channel 1 centred on 5005 MHz in the "5 GHz" section above that.
(As a side note, designating "5 GHz" and "6 GHz" as "separate bands" seems unjustified to me; the U-NII-2B radar protection gap is 120 MHz wide within the "5 GHz band", while the gap between the "5 GHz band" and the "6 GHz band" is only 50 MHz. Used this way the term "band" is at once both too coarse and too fine.)
Martin Kealey (talk) 12:57, 28 November 2023 (UTC)
thread_title:  Channel number for 5935 MHz 

message: After noting that some points seem rather dubious, despite being supported by citations, I've been trying to follow those citations to see what they really say.
This is a can of worms. Many of the citations simply refer to an entire act or regulation, often hundreds of pages, without noting any kind of internal anchor such as a section title or number, page number, or similar. This makes them worse than useless.
For example,
in footnote B of the 2.4 GHz section, the sentence "The 2.4 GHz Part 15 band in the US allows … channels 1 through 13" includes a reference, which only says:
* "dead link"➚. Archived from the original➚ on 2012-12-12. Retrieved 18 February 2014.
with two links:
* A. https://archive.today/20121212090129/http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr;sid=9eab2402bb1cccc8f85bb3fa9e6c2daa;rgn=div5;view=text;node=47:1.0.1.1.16;idno=47;cc=ecfr%2347:1.0.1.1.16.3.234.31
* B. https://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c%3Decfr%3Bsid%3D9eab2402bb1cccc8f85bb3fa9e6c2daa%3Brgn%3Ddiv5%3Bview%3Dtext%3Bnode%3D47%3A1.0.1.1.16%3Bidno%3D47%3Bcc%3Decfr#47:1.0.1.1.16.3.234.31
In case you're wondering how the archive URL can be shorter than the original, that's because the original is "over encoded", and should look like this:
* C. https://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr;sid=9eab2402bb1cccc8f85bb3fa9e6c2daa;rgn=div5;view=text;node=47:1.0.1.1.16;idno=47;cc=ecfr#47:1.0.1.1.16.3.234.31
The whole "archive.today" site is broken, as it's "protected" by a faulty captcha, so I trying searching on archive.org instead.
I found a single backup of the original (archived on 17 Oct 2014)
* D. https://web.archive.org/web/20141017200330/https://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr;sid=9eab2402bb1cccc8f85bb3fa9e6c2daa;rgn=div5;view=text;node=47:1.0.1.1.16;idno=47;cc=ecfr#47:1.0.1.1.16.3.234.31
when it was a redirection to
* E. http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr;sid=9eab2402bb1cccc8f85bb3fa9e6c2daa;rgn=div5;view=text;node=47%3A1.0.1.1.16;idno=47;cc=ecfr
which likewise has only a single backup (archived on the same day)
* F. https://web.archive.org/web/20141020231024/http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr;sid=9eab2402bb1cccc8f85bb3fa9e6c2daa;rgn=div5;view=text;node=47%3A1.0.1.1.16;idno=47;cc=ecfr
Link E currently says:
Please update your bookmark to: https://www.ecfr.gov/current/title-47/part-15
Additional details for the administrator of the site you came from:        The link        https://www.ecfr.gov/cgi-bin/text-idx?c=ecfr;sid=9eab2402bb1cccc8f85bb3fa9e6c2daa;rgn=div5;view=text;node=47%3A1.0.1.1.16;idno=47;cc=ecfr is no longer valid and should be replaced with https://www.ecfr.gov/current/title-47/part-15      
Critically, the original anchor #47:1.0.1.1.16.3.234.31 no longer works even if appended manually; the current site wraps each section in a div tag with an id= anchor that matches the legislative naming convention, like #p-15.3(a)(1).
This means one is faced with trying to find the intended referent among about 375000 visible letters and symbols (not counting space, line breaks, or any hypertext markup) or about 2300 paragraphs (and headings, bullet points, footnotes, etc).
This is by no means the only reference which fails to use sufficient precision; the overwhelming majority of reference descriptions simply name entire documents with no further information, and almost as many reference hyperlinks lack anchors or other section indicators.
In most countries, legislation has "stable" section and paragraph numbering (repealing or inserting paragraphs does not change the numbering of other paragraphs), so legal citations should always display the specific paragraph number, and include an equivalent anchor in the hyperlink.
Please if you add a new citation, include sufficient precision that it does not take hours of searching to find what you're referring to.
Martin Kealey (talk) 15:53, 4 December 2023 (UTC)
replies: text: عمارت 38.110.1.40 (talk) 18:12, 7 February 2024 (UTC)
thread_title:  Poor quality references 

message: It's False positive Sahib22 (talk) 10:56, 28 May 2024 (UTC)
replies: text: M 139.47.0.240 (talk) 16:35, 31 May 2024 (UTC)
thread_title:  Revision as of 09:02,28 may 2024