Hence, when using the 5Ghz channels after the 48th [i.e. 52 ~ 64 (U-NII-2), 100 ~ 144 (U-NII-2e)] DFS/TPC should be enabled to comply with the regulations. Similar regulations with slightly different power limits (1W/500mW/200mW e.i.r.p) apply to most of the world.
Here are my questions:
1. Does dd-wrt enable DFS/TPC when one of above channels is selected?
2. If that is not the case, which are the proper settings needed to comply with the EU regulations?
3. Are both DFS/TPC required? Or is it just enough to enable one?
I know it is a hard topic as it involves regulations.
Please don't say: "Just use the U-NII-1 channels[i.e. <= 48] to keep it simple."
Use case: There are all these channels which can be used to avoid interference in crowded environments like apartments.
[Running r50176 on Archer C9.]
Last edited by ndom on Tue Sep 27, 2022 7:32; edited 2 times in total
Joined: 31 Jul 2021 Posts: 2146 Location: All over YOUR webs
Posted: Tue Sep 27, 2022 19:38 Post subject:
ndom wrote:
Does that mean you don't care about regulations? What about dd-wrt?
That means that no single product is responsible for how its end users use it.
I'm in Europe and my Regulatory Domain is so set, so I do adhere to regulatory domains, as I dont have any valid reasons not to, but if I did have valid reason not to, that's my choice.
On that note I'm not about to tell you what channels I use, but you're welcome to park yourself outside the house and find out. What I can tell you my channels are picked accordingly to what neighboring networks dont use as to minimize interference.
When you select the appropriate regulatory domains your channel selection and width and DFS is limited accordingly and so it fulfills its obligations under regulations (hardware dependent), but some countries are more lax than others, so you can use whatever you want as long as you're not crossing over to any forbidden bands, so you can choose to follow or abandon regulations.
As for transmit power, you also have control over it, assuming your hardware allows it (some dont no matter what you set), but by default the transit power is set to conform with such regulations, now if you go around and decide to crank it up and your hardware allows it, who should be accountable for your choices? Similarly if you crank it up, one assumes you know what the implications are on signal quality and stability and collisions packet loss, error etc.
Also on some chipsets DD-WRT allows you Superchannel and that comes with its own legal disclaimer, it is a paid feature and even then its up to the user to decide to activate it and use it, its not DD-WRTs responsibility (or responsibility to police its users) what you do with your equipment or what options you have within it.
Choice is a wonderful thing to have.
What it seems is that you are looking for some specific information while keeping to the regulations use case, like you have a specific environment and what to setup the best way you can without risking a knock on the door. If so perhaps you care to make your real question known, none of your questions really indicate any such and are answered in a simple way anyway.
You can also stick to vendor firmware and the unpatched security issues and limited choices but know that no matter what you do or setup it wont ever fall outside any regulations because its locked to conform and lock you into any regulations it adheres to.
@the-joker, Thanks for your extensive reply and link.
It is interesting to find out that DFS requires capable hardware.
It is true, the questions are generic because I wanted to know how what are my choices.
To be more specific it would be good to know (and maybe added in the wiki):
- Are both DFS/TPC required for channels > 48 to comply with EU/US reg? Or is it just enough to enable one?
- Which are the DFS related settings in dd-wrt?
- Which are the TPC related settings in dd-wrt?
But that doesn't matter in 99% of cases anyway.
This reacts exclusively to so-called "primary users" such as high-power radar signals
And so that the radar detection triggers you have to live near a radar installation.
The FCC etc. give a radius of 35km.
Also, radars use a very specific frequency range (5570-5670Mhz / channel 116-132) and not the lower channels.
I live in the radar edge area of an airport (35km) and in my case the radar detection has never triggered and when I scan the WLAN here in the area I see that all DFS channels use.
On Broadcom routers you usually have the setting of the regulatory domain and the TPC mitigation factor.
It should be mentioned that WLAN routers do not have a high power anyway.
Depending on the building, the signals are very strongly attenuated anyway and little gets out.
and radar systems have several kW (kilowatt) power.
Joined: 31 Jul 2021 Posts: 2146 Location: All over YOUR webs
Posted: Wed Sep 28, 2022 8:57 Post subject:
I live within < 1KM radius of a Air force base who has their own separate Radar and other types of Radar/Technology equipment that is far superior to regular civilian Air transportation Radar and satellite bullshit. I dont actually use any of the ranges they use anyway, not that it would matter because my equipment would never interfere with their shit even at max transmit power of 1Watt. Also my WAN is provided via WiFi using a Ubiquity litebeam AC and it has tweaks for higher power range, since I live in the middle of nowhere, but still have neighbors with various WLAN setups and other equipment.
I can't have my CB/HAM/Other equipment setup for instance, even fully licensed due to my location and proximity I'm not allowed by law, even despite having the all clear from Base commander (which are the ones who monitor all frequencies in range), if I stayed within 20Watt transmit power and dont use some specific frequencies. But Im OK for using my portable radios no matter.
The US and FCC are those types of belt and braces kind, so they are more restrictive.
But Ontopic.
You have those main options to select from Broadcom side
Domain (previous name -- Regulatory Domain)
Mode (previous name -- Regulatory Mode)
TPC Mitigation Factor (aka good neighbor mode)
You also have transmit power and separate advanced settings that will conflict with the above settings.
The page is more or less documented mostly for Atheros, so bare that in mind.
Obviously DD-WRT allows you to stray from defaults and has for some chipsets like Atheros alternative radio firmwares that have more laxed implementations and Superchannel etc.
If you're really a stickler for regulations stick to defaults after choosing the correct country that matches your regulatory domain and set a strict Regulatory mode and TPC mitigation factor, understand TPC will reduce your radio transmit power, this may have an adverse effect your WLAN coverage.
You should check what your specific radios support and understand that none of these above things are guaranteed to work bug free.
Links above give you more information in addition to what ho1Aetoo said.
Thank you all for the guidance and for the very useful links.
I am happy to perform some DFS and TPC tests on the archer c9. Are there any related debug logs I can enable or CLI commands I can issue?
I have the tried following command but the value does not change even when I manually change the "TX Power" in Wireless_Advanced-wl1.asp. [The output of the command remains the same when I use the "802.11h strict" mode + "Mitigation Factor"]
Thank you all for the guidance and for the very useful links.
I am happy to perform some DFS and TPC tests on the archer c9. Are there any related debug logs I can enable or CLI commands I can issue?
I have the tried following command but the value does not change even when I manually change the "TX Power" in Wireless_Advanced-wl1.asp. [The output of the command remains the same when I use the "802.11h strict" mode + "Mitigation Factor"]
Code:
~# wl txpwr
31.75 dBm = 1496 mw
This is probably because you have not fully understood the syntax.
I mean how can the command display anything right if you don't specify the interface?
Regulatory 2,4Ghz and 5Ghz have different allowed transmit power depending on the channel.
Also, the command is used to set the transmit power and not to display the limits.
Apart from that the 1.5W is nonsense anyway as if the router would reach this power at all...
The router has a transmit power with 80Mhz and beamforming of maximum 26dB...
Completely regardless of what the driver says
(the radios have hardware limits and are tested - and the transmit power decreases with increasing channel width and higher modulation)