Dandemon
Level 2: Rookie

Channel width 2.4 Ghz setting keeps reverting to 20/40

On the Arcadyan LH1000 running the latest firmware at the time of posting (0.13.01r) I can't seem to get the wifi bandwidth to stick.

 

I set the 2.4Ghz wifi to a 20 Mhz bandwidth (which should really be its default, frankly) and despite what I do, it seems to revert to auto 20/40 Mhz within a day. I save the settings, I reboot the unit, I set it from the web ui and on my phone... no difference. It doesn't stay put at 20 Mhz. Other settings, such as the channel number, stick fine. I have the channel fixed to 6.

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7 REPLIES 7
Mkrtich
Level 21: Augmented
Level 21: Augmented

Re: Channel width 2.4 Ghz setting keeps reverting to 20/40

Hi - may I ask why you prefer to use the 20 Mhz setting. On Auto 20/40, my understanding is that the modem will only bond and connect the expansion 20 Mhz bandwidth to a capable device if it has the capacity at the time of request, otherwise it will use the 20 Mhz. Are you having any issues whilst the modem is on Auto 20/40? I also let my modem decide its channel by leaving it on Auto selection - I don't have a lot of Wi-Fi devices concurrently active. 

Dandemon
Level 2: Rookie

Re: Channel width 2.4 Ghz setting keeps reverting to 20/40

I think Apple says it best in its own recommendations:

  • 20 MHz for the 2.4 GHz band helps to avoid performance and reliability issues, especially near other Wi-Fi networks and 2.4 GHz devices, including bluetooth devices.

40 Mhz can really muck around with some clients, like smart TVs and even Google devices.  Response and download speeds can get really slow.  I have these issues on my iphone so I'm not doing this without reason.

cf4
Level 25: The Singularity
Level 25: The Singularity

Re: Channel width 2.4 Ghz setting keeps reverting to 20/40

Have you tried disabling band steering in the modem's 2.4 GHz WiFi settings which will add -5G to the 5 GHz WiFi name and then connecting  the iPhone only to the 5 GHz WiFi network?

Dandemon
Level 2: Rookie

Re: Channel width 2.4 Ghz setting keeps reverting to 20/40

Yes, band steering is disabled and I have a different name for the 2.4 and 5 Ghz networks.

 

The iphone can connect at 5 Ghz but the signal is weak, and it's not the only device having issues.  The TV, for example, can only do 2.4 Ghz.  When the channel width is 40 Mhz it crawls.

Mkrtich
Level 21: Augmented
Level 21: Augmented

Re: Channel width 2.4 Ghz setting keeps reverting to 20/40

The Auto 20/40 Mhz setting is an advertisement that the modem is capable of connecting at 40 Mhz when the circumstances allow which are very rare. If a device connects at that level, it will use 2 of the 3 non-overlapping channels laying the grounds for a potentially congested network, so I can understand why you are concerned. In order to protect their customers, my understanding is that Apple's policy is to limit  their devices to 20 Mhz operation on 802.11n 2.4Ghz networks and only allow higher bonded bandwidth of 40 Mhz on 802.11n 5Ghz and 80 Mhz on 802.11ac networks.

 

It is the device that determines how it will connect to the modem as its adapter capabilities define the rules of engagement, therefore it can not operate at higher levels even if they are available. I would expect that old or legacy 2.4Ghz devices to be also limited to 20 Mhz due to their age and low level cost technology entry points.

 

If you have a Mac, you can see  the active bandwidth connection being used by holding down Option and selecting the WiFi Icon at the top of the screen with your mouse. I have only seen our 8 year old Mac operate at 20 Mhz on 802.11n 2.4Ghz and 80 Mhz on 80-2.11ac 5Ghz - it is located at about 2 metres from its Access Point. I also have seen the same outcome at one of my friend's home, on a 6 month iMac 27" which was 10 metres from the Access Point as the 5Ghz signal was too weak due to inner walls.  

 

Does your TV show what bandwidth it is using for it's connection in it's Network Settings? If the connection speed of the active connection is visible in a TV settings, in the Windows Wi-Fi Adapter Properties of a PC or in the modem for a device, it can also be referenced to the 802.11n coding tables to confirm all the connection parameters that are being used by the Wi-Fi adapter in that device at that point of time.

 

Wi-Fi connections do strange or unexpected things - there may be other issues causing slow connection speeds in homes and sometimes an additional Access Point such as the Wi-Fi Booster Gen 2 may assist. 

 

Dandemon
Level 2: Rookie

Re: Channel width 2.4 Ghz setting keeps reverting to 20/40

The TV (like most TVs) isn't the cutting edge at wifi performance.  It doesn't report stats like a Mac or PC. 

 

While I accept that the device dictates the channel width it uses, performance when the modem is at Auto 20/40 Mhz is horrible compared to a dedicated 20 Mhz at the modem side.  I'm not dreaming that up.  All other routers I've owned since 802.11n became reality have had this option and I have always enjoyed better performance fixing them to 20 Mhz.  Always.

 

Getting back to the point - the UI lets me select 20 Mhz, the same way I select a fixed channel 6.  That's what I want.  It's a rural setting and there is no other wifi within half a kilometre.  The setting I select should stick.

 

There's some mention in threads of a "WiFi Dr." interfering with user settings and overriding them.  Is there some way to turn this off?  I see it scanning channels unnecessarily in the log file.

 

Mkrtich
Level 21: Augmented
Level 21: Augmented

Re: Channel width 2.4 Ghz setting keeps reverting to 20/40

Appreciate your feedback and experience. It may be a bug in the software - I don't know. My understanding from reading about the original Technicolor Wi-Fi Doctor via public web pages is that it is an Artificial Intelligence Cloud controlled platform that Telstra has incorporated into their centralised management system for remote monitoring the WiFi networks of both Smart Modems variants. The WiFi Doctor Agent is embedded in all Smart Modems, so it's a heavy hitting cloud based application when you consider there must be over a million Smart Modems in field by now. 

 

Originally developed by Technicolor and later sold to a company called Air Ties, the WiFi Doctor Agent periodically gets a AI initiated remote notice to undertake a check on the 'health' of the modem's  WiFi Network and number of devices utilising the 2.4Ghz band. It will survey the capabilities of all connected Wi-Fi devices and if it sees 5Ghz capable devices connected to 2.4GHz band, it will 'move' them over to the 5Ghz band  to optimise the network connections. I think the 5 Ghz band is managed by the Smart modem's integrated DFS Channel assignment by regulation (differs between models)  - not sure if the WiFi Doctor looks at the 5Ghz band - it may do, just can't recollect log entries at the moment. 

 

That's the theory. How it operates in practice, if at all when Band Steering is Disabled, is uncertain and in the early versions of firmware it caused some havoc by disconnecting 2.4 Ghz targeted devices. Maybe it is resetting the modem back to Auto 20/40? Most of the WiFi Doctor checks shown in the Log files of my LH:1000 seemed to have passed whatever tests were done with some occasional Channel swapping as I don't have many active concurrent in use 2.4 Ghz devices operating in home. 

 

Bandsteering is a propriety setting as there is no standard for it - how vendors apply it varies from turning down the broadcast power level of the 2.4 Ghz to low or very low, hiding its SSID ( some legacy devices can't see the modem unless Bandsteering is OFF) or lowering the power once a certain number of 2.4 Ghz devices connect. 

 

I understand Telstra is working on the 'next update', so hopefully things may change in the near future.

 

I recall from previous posts that some people discovered one device in home caused others to either disconnect from the modem or deliver poor performance to the network and the only way they determined this was to remove all WiFi devices and re-introduce them one at a time. Another post had two Mac PCs that were 5 metres from the modem and could not get decent speed - the OP addressed the problem by a counter-intuitive fix - he decreased the power output of the modem from its default 100% - maybe to 75 or 85% , can't recall. Strange things happen with WiFi.  

 

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