Asus AC68U How many AC-80MHz channels

[rt392]

I can operate at AC speeds up to 867Mbps on channel 36, to 48. Higher channels such as 149 to 161 can be made to function at lower bandwidths and lower (1/2) Mbps, 802.11n. Channels 149 to 165 AC are allowed in US I don't understand why the manufacturers disable them. I found the Netgear R7000 had the same issue.

In the 2.4GHz band all channels function N-only, 40MHz or slower. Gee.

This is my setup.
Asus AC68U, Firmware:Merlin 374.43_2. RT-N56U USB WiFi AC connected to Win 8.1 PC. Sony Xperia Z2 AC enabled smart phone and a couple of Netgear WiFi USB adapters to other equipment.

I changed NVRAM:
nvram set 0:ccode=#a
nvram set 1:ccode=#a
nvram set 0:regrev=0
nvram set 1:regrev=0
nvram set wl0_country_code=#a
nvram set wl0_country_rev=0
nvram set wl0_reg_mode=off
nvram set wl1_country_code=#a
nvram set wl1_country_rev=0
nvram set wl1_reg_mode=off
nvram commit
reboot

With this setup I have a large assortment of 5G channels most aren't recognized by the receiving equipment in the US.
The routers 5G wireless settings are N+AC, 80MHz bandwidth, Control Channel 48, extension channel Auto. This forces AC operation and works on PC at 867Mbps depending on distance from router. I change the channel to test other channels. I verify channels with smart phone being international and can work where the PC wont. It also doesn't see the 149 to 165 80MHz channels.

Ray

 

[watusi]

There are actually precious few channels you can actually use.

36, 40, 44, 48, OK.

52, 56, 60, 64 subject to DFS. The router has to listen for radar and block-out the channels if found. I'm right above two airports...

Channels 100,104,108,112,116,132,136,140 are restricted to "professionally installed" equipment, whatever that means and subject to DFS. (I think these are for outdoor point-point.)

Channels 120,124,128 are not allowed.

That leaves us with 149,153,157,161,165

As a practical matter, there are two possible 80mHz channels. In a high-density area, it's unlikely you will find one interference-free.

 

[kenhlan]

What he said...

Channels 149, 153, 157, and 161, are all near the DFS region of channels, and have to conform to the FCC regs on TDWR or military freq interference.

In my local area, in those channels, I've only had up to 40Mhz bandwidth on either 157 or 161 (channel pairs), with any degree of stability.

20Mhz (narrow bandwidth), I've had success with on all those upper channels. 80Mhz (which combines them all), I've had no success in my area, as the router shut them off from detected interference.

I guess there are two camps in the wireless manufacturers. Only make the lower channels available to select, or make all the legal channels available, and demonstrate interference processing to achieve FCC cert to use/show them.

I learned more about this phenomenon and DFS in the last couple of weeks than I ever cared to know.

quick read here: http://www.networkcomputing.com/wir...on-part-3-the-channel-dilemma/a/d-id/1234489?

 

[wouterv]

Wireless networking requires a real new boost.
2.4 GHz leaves us with practical 3 channels out of the theorethical 11-13 ones, and often even those 3 are too occupied.
5 GHz leaves us with with only a few usable channels: 802.11n does quite fine with the 4 lower channels, 802.11ac struggles with the DFS requirements.
I presonally do not expect miracles from the current 2.4 GHz and 5 GHz.
The fastest network is still wired, for wireless solutions over a larger area you shall not rely on just one access point, but spread them around the house (one in each room for 5 GHz, connected by wires or over the powerlines).
The real future lies in new frequencies that are not shared with other applications and without overlapping channels.

 

[jegesq]

Ray:

First, you wrote: "In the 2.4GHz band all channels function N-only, 40MHz or slower. Gee"

802.11 first utilized 20 MHz channels from the beginning (with the standardization of OFDM in 802.11a, and with 802.11b and g). Later, when 802.11n was implemented, it allowed 40 MHz channels to be used. That is the maximum channel width permitted in the 2.4ghz spectrum. So when you say "Gee", that should not come as any surprise, since that's the limit in the 2.4ghz band.

The 802.11ac standard brings two new channel sizes: 80mhz and 160mhz (the 160mhz is for the second "wave" and it's not been implemented yet). As expected, wider channels bring higher throughput.

You wrote: "Higher channels such as 149 to 161 can be made to function at lower bandwidths and lower (1/2) Mbps, 802.11n."

Yes, if you connect an 802.11n device to the 5ghz channel, even if it's set at 80mhz, it will drop down to 40mhz channel width in order to maintain backwards compatibility with the 802.11n device.

You also wrote: "Channels 149 to 165 AC are allowed in US I don't understand why the manufacturers disable them. I found the Netgear R7000 had the same issue."

Channel availability is a matter of governmental regulations, not what the chip in the router or client device may be capable of. You can select channels 149, 153, 157 and 161 as your primary channel for the 5ghz band because the FCC allows these channels to be used in the U.S. Channels other these four were NOT authorized for unlicensed use by the FCC in the U.S. when the FCC opened the 5.735-5.825mhz spectrum up. Other channels in that spectrum (such as 150, 152, 156, and so on) are "disabled" in the firmware so manufacturers can comply with FCC regs.

I am not certain what you are doing with the country code of your AC68U (trying to change it to European setting? Japan?). Even if you were changing the setting of the country code to something other than U.S., and even if you're using an "international" smartphone, channels 149 to 165 are not licensed to be used in Europe (or anywhere else "internationally"). So, if you use a smartphone that is "international" (i.e., not set to U.S.), it won't be able to receive or transmit on those channels anyway because they're not available to a device that's not set to U.S. specs.

 

[jegesq]

Ray,

Also, As noted in the excellent book by Matthew S. Gast, "802.11ac: A Survival Guide" (published by Oreilly online):

"Wireless LAN equipment is built with flexible radio chips that can tune to almost any frequency, and the 802.11 standards have defined a large number of channels. 802.11ac continues to use the same channel numbering defined by its predecessors...Channel numbers are spaced four digits apart, but within a wide channel, one of the frequencies is designated as the primary channel; others are called secondary channels. When used as part of an 80 MHz channel, channel 44 may be the primary channel, and channels 36, 40, and 48 will all be secondary channels. Generally speaking, when operating, a wireless LAN will send Beacon frames and announce its existence on its primary channel, but not on its secondary channels."

Gast explains further:

"Essentially, 802.11 has always been a “listen-before-talk” protocol in which gaps in the transmission medium usage are an important component of the coordination process that divides up access to the medium among many stations. An important component of the 802.11ac standard is the way that a BSSID can switch channel bandwidth dynamically on a frame-by-frame basis. In any given collection of devices, it is easy to see how some might be line-powered devices without power-saving requirements and demanding the highest possible throughput, while others are battery-operated devices where battery life is at a premium. Rather than enforcing a one-bandwidth-fits-all approach, 802.11ac allows channel bandwidth to be determined on a frame-by-frame basis.

"By selecting the channel bandwidth to be used on a per-frame basis, 802.11ac can more efficiently use the available spectrum. When a wide channel is available, high data rates are possible. When only a narrow channel is available, 802.11ac can fall back to lower rates."

This would explain why, even if you've set your device to use an 80mhz width channel on the 5ghz band with 802.11ac, it might have to drop from 80mhz to 40mhz, and thus to lower theoretical maximum connection speeds.

And it also explains why an "international" smartphone can't use Channels 149-165.

 

[jegesq]

What he said...

Channels 149, 153, 157, and 161, are all near the DFS region of channels, and have to conform to the FCC regs on TDWR or military freq interference.

In my local area, in those channels, I've only had up to 40Mhz bandwidth on either 157 or 161 (channel pairs), with any degree of stability.

20Mhz (narrow bandwidth), I've had success with on all those channels. 80Mhz (which combines them all), I've had no success in my area, as the router shut them off from detected interference.

I guess there are two camps in the wireless manufacturers. Only make the lower channels available to select, or make all the legal channels available, and demonstrate interference processing to achieve FCC cert to use/show them.

I learned more about this phenomenon and DFS in the last couple of weeks than I ever cared to know.

quick read here: http://www.networkcomputing.com/wir...on-part-3-the-channel-dilemma/a/d-id/1234489?

Ken:

Yesterday, I responded with a very long answer and take on something you posted that was similar to the above quote (in a different thread), but alas, with the loss of the messages, it evaporated into the ether and I really can't retype the entire thing again.

But your issue might also be related simply to coexistence and not so much directly to DFS. Take a look at the e-book I cited above, Matthew S. Gast's book "802.11ac: A Survival Guide". It's excellent and very comprehensive, yet understandable and actually a pretty quick read. Pay attention to his material on "coexistence" as it will be illuminating. The book is available at this link (and you don't have to buy it, just click on "read online"):http://chimera.labs.oreilly.com/books/1234000001739/index.html

 

[kenhlan]

Thanks jegs. Running out the door, but will read it when I get back.

I also posted a response to your and wouterv responses, which were lost also...



The gist was I connected up a couple of clients, and I did not witness any active channel notification and switch actions, during the signal cut off events.

I did verify my theory that at least Channels 157 and 161 at 40Mhz bandwidth was relatively stable. (IMO, 149 and 153 are too close to the regulated freqs to pair at 40Mhz in my area without ACI (adjacent channel interference spread) into the regulated freqs.)

Too many folks looking and posting 'issues' related to 5G connectivity and stability to be uncharacterized, only viewed as an individual problem, especially considering 2.4G as a known stability point of reference, and considering the frequent recommendation on 5G 'issues' threads to move to 'lower channels, there's 'something' universal up with those channel, (149, 151, 153, 157, 161) and the common denominator is DFS management, particularly interference detection response in my area, IMO.

I'll go back and post my first response to the other poster to start that discussion again. (I happened to reply to a PM from him, that remained intact after the site restore..)

 

[rt392]

There are actually precious few channels you can actually use.

36, 40, 44, 48, OK.

52, 56, 60, 64 subject to DFS. The router has to listen for radar and block-out the channels if found. I'm right above two airports...

Channels 100,104,108,112,116,132,136,140 are restricted to "professionally installed" equipment, whatever that means and subject to DFS. (I think these are for outdoor point-point.)

Channels 120,124,128 are not allowed.

That leaves us with 149,153,157,161,165

As a practical matter, there are two possible 80mHz channels. In a high-density area, it's unlikely you will find one interference-free.

Yes. With a Netgear R7000 AC1900 If you setup to send AC on the lower group of channels 36 to 48 you get a pop-up note saying better performance will happen on the higher 149 to 165 group. In the US (at least) the AC router will not function on the upper group. The same as AC68U.

Check the links, the lower group has limits and the upper group doesn't.
http://en.wikipedia.org/wiki/List_of_WLAN_channels
http://en.wikipedia.org/wiki/IEEE_802.11ac

Ray

 

[kenhlan]

Ken:

Yesterday, I responded with a very long answer and take on something you posted that was similar to the above quote (in a different thread), but alas, with the loss of the messages, it evaporated into the ether and I really can't retype the entire thing again.

But your issue might also be related simply to coexistence and not so much directly to DFS. Take a look at the e-book I cited above, Matthew S. Gast's book "802.11ac: A Survival Guide". It's excellent and very comprehensive, yet understandable and actually a pretty quick read. Pay attention to his material on "coexistence" as it will be illuminating. The book is available at this link (and you don't have to buy it, just click on "read online"):http://chimera.labs.oreilly.com/books/1234000001739/index.html

Did a quick read of that guide. It seems the coexistence discussion is geared toward multiple network co-existence. There aren't any additional 5G networks as I can scan/identify around me, so not sure that directly applies. I'm still reading it, but didn't find any indepth discussion on radar detection/interference, although it was mentioned in passing once. Still reading it. Some good theoretical info in there.

BTW - It looks like our lost exchanges was restored in the other thread, so I'll get off potentially hijacking this one.

 

[rt392]

Your network computing link has the same capabilities as I wrote.
There are 2 sets of channels to send at 80MHz. 36-48 and 149-161 and no DFS or other restraints. The Netgear R7000 and the AC68U both will not send 80 MHz on 149-161. I read that some other countries do function so I changed my firmware to test this performance. The AC68U (while giving me the option of more channels indicating my country change worked) refuses to send 80MHz on 149-161.

This means we have one spot to use for AC performance.

Ray

What he said...

Channels 149, 153, 157, and 161, are all near the DFS region of channels, and have to conform to the FCC regs on TDWR or military freq interference.

In my local area, in those channels, I've only had up to 40Mhz bandwidth on either 157 or 161 (channel pairs), with any degree of stability.

20Mhz (narrow bandwidth), I've had success with on all those upper channels. 80Mhz (which combines them all), I've had no success in my area, as the router shut them off from detected interference.

I guess there are two camps in the wireless manufacturers. Only make the lower channels available to select, or make all the legal channels available, and demonstrate interference processing to achieve FCC cert to use/show them.

I learned more about this phenomenon and DFS in the last couple of weeks than I ever cared to know.

quick read here: http://www.networkcomputing.com/wir...on-part-3-the-channel-dilemma/a/d-id/1234489?

 

[jegesq]

Your network computing link has the same capabilities as I wrote.
There are 2 sets of channels to send at 80MHz. 36-48 and 149-161 and no DFS or other restraints. The Netgear R7000 and the AC68U both will not send 80 MHz on 149-161. I read that some other countries do function so I changed my firmware to test this performance. The AC68U (while giving me the option of more channels indicating my country change worked) refuses to send 80MHz on 149-161.

This means we have one spot to use for AC performance.

Ray

Ray, what country are you in? Just curious. I presume U.S., because you write that you changed your country code to something other than U.S. to test whether you could connect using 141-169 and it didn't work for you. I think the reason that would be so, is that when you switch to any other country code other than U.S., the router will not broadcast on those channels, since they are authorized only to be used in the U.S. from what I understand. So when you switch the country code from U.S., you're really only confirming that you've switched it, nothing more IMHO.

Ken says that he doesn't experience a complete lack of signal; rather he says he experiences a signal that is completely unstable and which connects and disconnects "aperiodically" (i.e., at completely irregular intervals). He has never said that he cannot connect at all when using channels 149-161 when set at 80mhz, at least I don't think that's what he's ever described.

You say, however, that neither the R7000 nor the AC68U will actually even send a signal out if set to 80mhz and using channels 149-161. I have not used the R7000, so I can't comment on that, but I am skeptical about the statement. I have used the AC68U and the AC66U, and I frankly do not agree. You have therefore concluded there's really only one set of channels (the lower band) which is actually available in the 5ghz spectrum using 80mhz channel bandwidth. That does not comport with my experiences.

With all due respect, I'm not certain how you're testing this (other than setting your country code to something other than U.S., which will in fact prove that you can't broadcast on 149-161 for the reason stated above). But if you're set to U.S., then likewise, your router should be broadcasting on 149-161, even at 80 MHz (whether stable or not, or whether it turns on or off is another question entirely).

What makes me think that whatever is going on with both you and Ken (and I think it's two different things) is probably peculiar to each of your particular environments. He at least says he gets a signal, albeit unstable, whereas you say you get nothing. That clearly can't describe the same situation. And what makes me believe this is a unique issue confined to Ken's and your environs also is that Ken also wrote that when using two different AC66U's he experienced the same inability to maintain any sort of stability when using channels 149-161 set at 80mhz and even at 40mhz. He attributes that to some nearby signal interference. Could be. I presently am using two AC66U's, (one as a router, the other as a repeater), both set to 80mhz channel widths, and both assigned to channel 161 as the primary (thus bonding 161 with 149, 153 and 157 to get the 80mhz width), and I have experienced none of the issues that he, or you, say you've experienced. No instability, no dropped signals, no on and off of the radios, and I get a consistent signal at both ends.

I'm also not particularly sold on Ken's theory that what is causing his problem is interference from nearby military, naval, weather or airport radios and radar either. As you note, DFS isn't a restriction in either the upper or lower bands that are exposed on the Asus routers, but I'm just not sold on your theory that the AC68U just won't send out a signal if set to U.S. and 80mhz if using 149-161. In my mind, it's just got to be something else. Perhaps the clients you guys are using to test? Some other setting on the router that is causing instability? I don't know. But neither of you describe the same symptoms, so I'm not sure your issue describes or will inform us about how to solve Ken's, and vice-versa.

 

[jegesq]

Ray, one more thought:

While you say that DFS doesn't apply to 36-48 or 149-161, and that's technically correct, what Ken is suggesting, and what is depicted in his crossover diagram in this post is that both channels 48 and 149 do have an area of "overlap" that potentially crosses over into the DFS-protected channel areas. So the theory goes, if DFS detection is triggered, it causes the router to look for non-interfering channels, and since there's no way to continue to maintain 80mhz when that occurs (because there are effectively only two ranges of 80mhz channels), you'll lose one or both, and thus can only tx/rx at 40mhz max on he 5ghz band. As the author of the Networking article linked above wrote:

"If any part of a channel touches a defined DFS frequency, then that channel is off-limits if a radar is detected, or if DFS channels are not in use. Wider channels mean more opportunity to overlap a DFS frequency. This is why the 802.11ac standard with 80 MHz wide channels has more complications with DFS than previous standards with 20-40 MHz wide channels."

So perhaps you're both right, just not for the same reasons....just a thought.

 

[kenhlan]

Just to be clear, the signal shuts off.

Here is an EARLY video I took when I first was trying to figure what was going on....

http://vid154.photobucket.com/albums/s257/kenhdog/General/AC66_5G_Channel_drop_zpsh1wiibex.mp4

At that time, the B/W was set to 20/40/80. Since that video, and testing with other bandwidth/channel combinations, is where I since posted my more detailed characterization table.

rt392's experience looks similar to me. He might try the other combinations to determine his particular characterizations.