3 ms·

> "are the amateur/unlicensed uses that are starved of bandwidth (Wi-Fi does strike me as something that fits but is there anything else)?" WiFi 6e / WiFi 7 ar

> "are the amateur/unlicensed uses that are starved of bandwidth (Wi-Fi does strike me as something that fits but is there anything else)?" WiFi 6e / WiFi 7 are getting a huge swath of bandwidth between 5.9 and 7.1Ghz in the US and Canada (but somewhat less in Europe/Japan/Australia/etc) Even with current 5 Ghz WiFi, a lot of routers seem to not let you select the DFS/TPC channels above 48 even though they're perfectly legal to use in most places. As a result, those channels are far less congested.

dan-robertson 4y ago
I thought there was some tricky channel switching logic because of some other non-Wi-Fi uses of part of the 5GHz band, so maybe service degradation when switching away or just disabling the channels for a long time when the conflict-detection fires causes those channels to not be used much?
- Reason077 4y ago
  I've certainly never noticed it switch channels on me in all the years I've been using it in the UK.
varenc 4y ago
The DFS channels have big downsides though. I don’t know much about TPC but for DFS, if your access point is on a DFS channel and it detects weather radar usage there it has to immediately get off it. It also has a slow start up period where it must first listen for radar traffic before transmitting. Though if you’re in an area without any radar on those bands it could be well worth it.
- Reason077 4y ago
  Yeah, it does increase boot time a bit while the initial scan happens. But hopefully you aren't rebooting your router too often anyway. Small price to pay for avoiding WiFi congestion if you're in a busy building/area. It's a huge performance penalty if some other nearby network is sharing your channel, so DFS is one small downside for a very big upside, IMO!
- wtallis 4y ago
  In the US, it's only one specific type of weather radar (TDWR), which is only used at 45 major airports. If you don't live near one of those, you only have to worry about a false positive in the radar detection feature accidentally knocking you off a DFS channel. And I know from experience that local topography sometimes means you can be operating an AP on a DFS channel only a few miles from one of those airports without ever having a problem.
  - sidewndr46 4y ago
    It isn't really that simple. There are other users like satellite equipment & military radar. The military radar in particular runs anywhere they want at anytime without disclosing their actual location. The equipment itself also has false positives, which lead to much of it being unusable.
    - Reason077 4y ago
      > "The equipment itself also has false positives" This has never noticeably happened in my experience (UK). I've used DFS bands on my routers for years. It's far worse to use non-DFS bands because if you live in a built-up area they are almost always congested, causing poor performance (latency spikes, packet loss, etc).
kccqzy 4y ago
I discovered that not all devices (stations not APs) support those channels. Many smart TVs in particular do not support them. https://www.reddit.com/r/Roku/comments/als768/why_do_roku_devices_not_support_dfs_channels/ https://www.reddit.com/r/Roku/comments/als768/why_do_roku_de...
- Reason077 4y ago
  Personally I've never encountered a device (as opposed to an AP) that didn't work with DFS channels. There's certainly some devices (cheap WiFi light bulbs, or anything really old) that don't support 5 Ghz at all, but any 5 Ghz device I've ever used found my DFS AP just fine. 5 Ghz WiFi bandwidth is really severely limited without DFS. If you're using an 80 Mhz channel then you're using almost the entire available non-DFS bandwidth, overlapping/conflicting with nearly all other nearby non-DFS networks. But with DFS there's room for 7 non-overlapping 80 Mhz channels!
  - sidewndr46 4y ago
    You must just not be looking. It was standardized in 2003. Anything before that isn't going to have it. Even "new" products aren't going to have it mandatorily. I have laptop from 2013 that is 2.4 Ghz only for example.
    - Reason077 4y ago
      Yes, of course there's plenty of old 2.4 GHz-only devices around. But in my experiences, devices (but not all APs) which support 5 GHz WiFi tend to support all 5 GHz bands, including DFS bands (channel > 48) just fine.
      - kccqzy 4y ago
        Tell them to millions of disappointed customers of Roku TV.

dan-robertson 4y ago

I thought there was some tricky channel switching logic because of some other non-Wi-Fi uses of part of the 5GHz band, so maybe service degradation when switching away or just disabling the channels for a long time when the conflict-detection fires causes those channels to not be used much?

Reason077 4y ago
I've certainly never noticed it switch channels on me in all the years I've been using it in the UK.

varenc 4y ago

The DFS channels have big downsides though. I don’t know much about TPC but for DFS, if your access point is on a DFS channel and it detects weather radar usage there it has to immediately get off it. It also has a slow start up period where it must first listen for radar traffic before transmitting. Though if you’re in an area without any radar on those bands it could be well worth it.

Reason077 4y ago
Yeah, it does increase boot time a bit while the initial scan happens. But hopefully you aren't rebooting your router too often anyway. Small price to pay for avoiding WiFi congestion if you're in a busy building/area. It's a huge performance penalty if some other nearby network is sharing your channel, so DFS is one small downside for a very big upside, IMO!
wtallis 4y ago
In the US, it's only one specific type of weather radar (TDWR), which is only used at 45 major airports. If you don't live near one of those, you only have to worry about a false positive in the radar detection feature accidentally knocking you off a DFS channel. And I know from experience that local topography sometimes means you can be operating an AP on a DFS channel only a few miles from one of those airports without ever having a problem.
- sidewndr46 4y ago
  It isn't really that simple. There are other users like satellite equipment & military radar. The military radar in particular runs anywhere they want at anytime without disclosing their actual location. The equipment itself also has false positives, which lead to much of it being unusable.
  - Reason077 4y ago
    > "The equipment itself also has false positives" This has never noticeably happened in my experience (UK). I've used DFS bands on my routers for years. It's far worse to use non-DFS bands because if you live in a built-up area they are almost always congested, causing poor performance (latency spikes, packet loss, etc).

kccqzy 4y ago

I discovered that not all devices (stations not APs) support those channels. Many smart TVs in particular do not support them. https://www.reddit.com/r/Roku/comments/als768/why_do_roku_devices_not_support_dfs_channels/ https://www.reddit.com/r/Roku/comments/als768/why_do_roku_de...

Reason077 4y ago
Personally I've never encountered a device (as opposed to an AP) that didn't work with DFS channels. There's certainly some devices (cheap WiFi light bulbs, or anything really old) that don't support 5 Ghz at all, but any 5 Ghz device I've ever used found my DFS AP just fine. 5 Ghz WiFi bandwidth is really severely limited without DFS. If you're using an 80 Mhz channel then you're using almost the entire available non-DFS bandwidth, overlapping/conflicting with nearly all other nearby non-DFS networks. But with DFS there's room for 7 non-overlapping 80 Mhz channels!
- sidewndr46 4y ago
  You must just not be looking. It was standardized in 2003. Anything before that isn't going to have it. Even "new" products aren't going to have it mandatorily. I have laptop from 2013 that is 2.4 Ghz only for example.
  - Reason077 4y ago
    Yes, of course there's plenty of old 2.4 GHz-only devices around. But in my experiences, devices (but not all APs) which support 5 GHz WiFi tend to support all 5 GHz bands, including DFS bands (channel > 48) just fine.
    - kccqzy 4y ago
      Tell them to millions of disappointed customers of Roku TV.