2.4ghz is slow on TP-Link Archer A7

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arnath
DD-WRT Novice


Joined: 05 Apr 2019
Posts: 5

PostPosted: Mon Jun 17, 2019 13:25    Post subject: 2.4ghz is slow on TP-Link Archer A7 Reply with quote
Hi,

I have DD-WRT installed on a TP-Link Archer A7 (Firmware v3.0-r39296 std 03/27/19). My DD-WRT router is connected to a ISP provided Fritz!Box 7430 which is a DSL modem and router. I was messing around with my WiFi configs today and found something odd. The Archer A7 is dual band and the Fritz!Box only supports 2.4ghz so I setup three networks and did speed tests and got these results:

Fritz!Box 2.4ghz: ~80 Mbps
Archer 2.4ghz: ~20 Mbps
Archer 5ghz: ~90 Mbps

Can someone please help me try to figure out why the 2.4ghz radio on the DD-WRT router is working so slowly? Both 2.4ghz networks are running on the same channel so I don't think it's a channel congestion issue. I'm not really sure how to go about debugging this.
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ian5142
DD-WRT Guru


Joined: 23 Oct 2013
Posts: 1983
Location: Canada

PostPosted: Mon Jun 17, 2019 16:47    Post subject: Recommended Settings Reply with quote
First make sure you are using the recommended settings on the Archer A7: https://wiki.dd-wrt.com/wiki/index.php/Atheros/ath_wireless_settings

Also, you are not using the latest build: https://wiki.dd-wrt.com/wiki/index.php/Index:FAQ#Where_do_I_download_firmware.3F

Notes, in order to get max speed on 2.4GHz you need:
HT40 channel width
a clear channel (1, 6, or 11 are best).
Open or WPA2+AES security (not WEP or WPA).
Short Preamble and Short GI are enabled
WMM Support must be enabled.
Antenna chains, don't change them from the default unless you know what you are doing.

_________________
Before asking a question on the forums, update dd-wrt: Where do I download firmware? I suggest reading it all.

Some dd-wrt wiki pages are up to date, others are not. PM me if you find an old one, I am trying to update them.

Atheros:
TP-Link Archer C7 v2 x2 - WDS AP, WDS Station
TP-Link TL-WDR3600 v1 - WDS Station
TP-Link 841nd v8 - WDS Station
Linksys WRT400N - bricked
D-Link 615 C1 x 4 - not used
D-Link 615 E3 x 2 - WDS Station
D-Link 825 B1 - WDS Station
D-Link 862L A1 - WDS Station (Entware 3X)
Netgear WNDR3700v2 - WDS Station
TP-Link 1043nd v1, inactive, unstable hardware
UBNT loco M2 x2 - airOS

Broadcom
Asus N66U - backup Gateway
Netgear r6300 v1 - AP
Linksys E2500 - not used
Linksys EA2700 - not used
Linksys 160N v3 x2 - not used
Netgear WNDR3700v3 - not used
MediaTek
UBNT EdgeRouter X - Gateway, DHCP, QoS
egc
DD-WRT Guru


Joined: 18 Mar 2014
Posts: 3514
Location: Netherlands

PostPosted: Mon Jun 17, 2019 17:02    Post subject: Re: 2.4ghz is slow on TP-Link Archer A7 Reply with quote
arnath wrote:

Can someone please help me try to figure out why the 2.4ghz radio on the DD-WRT router is working so slowly? Both 2.4ghz networks are running on the same channel so I don't think it's a channel congestion issue. I'm not really sure how to go about debugging this.


"Both 2.4 GHz radios are on the same channel" is the definition of network congestion.

Use Wifi analyzer on your phone to look for a free non overlapping channels (and of course Ian's settings Smile )

_________________
Routers: Netgear R6400v1, Netgear R6400v2, Linksys EA6900 (XvortexCFE), Linksys E2000 (converted WRT320N), WRT54GS v1.
Install guide Linksys EA6900: http://www.dd-wrt.com/phpBB2/viewtopic.php?t=291230
Simple PBR (Policy Based Routing) script: https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=318662
Install guide R6400v2:http://forum.dd-wrt.com/phpBB2/viewtopic.php?t=316399
OpenVPN server setup guide:
https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=318795
arnath
DD-WRT Novice


Joined: 05 Apr 2019
Posts: 5

PostPosted: Mon Jun 17, 2019 19:36    Post subject: Reply with quote
I meant that the issue isn't congestion with other networks in my apartment because they're both on the same channel and should degrade the same amount because of that.

I have tried turning off one of the 2.4ghz radios at a time so there was only one WiFi network being broadcast at a time and that didn't change the outcome at all. Also, if the issue is strictly congestion from the other network, both 2.4ghz networks would be slow and the one on my Fritz!box works great.
ian5142
DD-WRT Guru


Joined: 23 Oct 2013
Posts: 1983
Location: Canada

PostPosted: Mon Jun 17, 2019 19:50    Post subject: Wireless Settings Reply with quote
Post a screenshot of your wireless settings (including the advanced checkbox) on the Archer A7.

It is best to zip up the file, either .zip or .7z

The forum software is old and does not handle large photos well.

_________________
Before asking a question on the forums, update dd-wrt: Where do I download firmware? I suggest reading it all.

Some dd-wrt wiki pages are up to date, others are not. PM me if you find an old one, I am trying to update them.

Atheros:
TP-Link Archer C7 v2 x2 - WDS AP, WDS Station
TP-Link TL-WDR3600 v1 - WDS Station
TP-Link 841nd v8 - WDS Station
Linksys WRT400N - bricked
D-Link 615 C1 x 4 - not used
D-Link 615 E3 x 2 - WDS Station
D-Link 825 B1 - WDS Station
D-Link 862L A1 - WDS Station (Entware 3X)
Netgear WNDR3700v2 - WDS Station
TP-Link 1043nd v1, inactive, unstable hardware
UBNT loco M2 x2 - airOS

Broadcom
Asus N66U - backup Gateway
Netgear r6300 v1 - AP
Linksys E2500 - not used
Linksys EA2700 - not used
Linksys 160N v3 x2 - not used
Netgear WNDR3700v3 - not used
MediaTek
UBNT EdgeRouter X - Gateway, DHCP, QoS
arnath
DD-WRT Novice


Joined: 05 Apr 2019
Posts: 5

PostPosted: Mon Jun 17, 2019 23:08    Post subject: Reply with quote
I have attached a PDF (using print to PDF from the admin page). If that doesn't work, let me know and I'll get some screenshots.

FWIW, I tried updating my firmware to build 40048 and that did not change the issue.



dd-wrt.pdf
 Description:

Download
 Filename:  dd-wrt.pdf
 Filesize:  464.05 KB
 Downloaded:  13 Time(s)

ian5142
DD-WRT Guru


Joined: 23 Oct 2013
Posts: 1983
Location: Canada

PostPosted: Tue Jun 18, 2019 18:08    Post subject: Wireless Settings Reply with quote
Read the recommended settings from here: https://wiki.dd-wrt.com/wiki/index.php/Atheros/ath_wireless_settings

Set up the 2.4GHz and 5GHz using the recommended settings.

Did you even read any of the responses to your first post?

_________________
Before asking a question on the forums, update dd-wrt: Where do I download firmware? I suggest reading it all.

Some dd-wrt wiki pages are up to date, others are not. PM me if you find an old one, I am trying to update them.

Atheros:
TP-Link Archer C7 v2 x2 - WDS AP, WDS Station
TP-Link TL-WDR3600 v1 - WDS Station
TP-Link 841nd v8 - WDS Station
Linksys WRT400N - bricked
D-Link 615 C1 x 4 - not used
D-Link 615 E3 x 2 - WDS Station
D-Link 825 B1 - WDS Station
D-Link 862L A1 - WDS Station (Entware 3X)
Netgear WNDR3700v2 - WDS Station
TP-Link 1043nd v1, inactive, unstable hardware
UBNT loco M2 x2 - airOS

Broadcom
Asus N66U - backup Gateway
Netgear r6300 v1 - AP
Linksys E2500 - not used
Linksys EA2700 - not used
Linksys 160N v3 x2 - not used
Netgear WNDR3700v3 - not used
MediaTek
UBNT EdgeRouter X - Gateway, DHCP, QoS
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