# TL-WN851ND : no 802.11n available

## Tom_

Hello, 

I've got a TL-WN851ND wifi adapter in my computer. I just found out that this adapter only sees 2.4 ghz frequencies. That would explain why it has been so slow ... 

The adapter specs are : https://www.tp-link.com/en/products/details/TL-WN851ND.html#specifications

My AP runs at 2.4 and 5 ghz. 

```
thomas@gentoo ~ % lspci -vvnn | grep Network -A7 

06:01.0 Network controller [0280]: Qualcomm Atheros AR9227 Wireless Network Adapter [168c:002d] (rev 01) 

       Subsystem: Qualcomm Atheros AR9227 Wireless Network Adapter [168c:0300] 

       Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- 

       Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- 

       Latency: 168, Cache Line Size: 4 bytes 

       Interrupt: pin A routed to IRQ 16 

       Region 0: Memory at faff0000 (32-bit, non-prefetchable) [size=64K] 

       Capabilities: <access denied> 

       Kernel driver in use: ath9k
```

```
thomas@gentoo ~ % iwlist wlp6s1 frequency 

wlp6s1    13 channels in total; available frequencies : 

         Channel 01 : 2.412 GHz 

         Channel 02 : 2.417 GHz 

         Channel 03 : 2.422 GHz 

         Channel 04 : 2.427 GHz 

         Channel 05 : 2.432 GHz 

         Channel 06 : 2.437 GHz 

         Channel 07 : 2.442 GHz 

         Channel 08 : 2.447 GHz 

         Channel 09 : 2.452 GHz 

         Channel 10 : 2.457 GHz 

         Channel 11 : 2.462 GHz 

         Channel 12 : 2.467 GHz 

         Channel 13 : 2.472 GHz 

         Current Frequency:2.462 GHz (Channel 11)
```

```
thomas@gentoo ~ % iwconfig 

wlp6s1    IEEE 802.11  ESSID:"CXNK0041D527"  

          Mode:Managed  Frequency:2.462 GHz  Access Point: CC:BE:59:39:EF:97   

          Bit Rate=57.8 Mb/s   Tx-Power=19 dBm   

          Retry short limit:7   RTS thr:off   Fragment thr:off

          Power Management:off

          Link Quality=42/70  Signal level=-68 dBm  

          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0

          Tx excessive retries:0  Invalid misc:76   Missed beacon:0
```

```
thomas@gentoo linux % grep CFG80211 /usr/src/linux/.config 

CONFIG_CFG80211=m 

# CONFIG_CFG80211_DEVELOPER_WARNINGS is not set 

# CONFIG_CFG80211_CERTIFICATION_ONUS is not set 

CONFIG_CFG80211_DEFAULT_PS=y 

# CONFIG_CFG80211_DEBUGFS is not set 

# CONFIG_CFG80211_INTERNAL_REGDB is not set 

CONFIG_CFG80211_CRDA_SUPPORT=y 

CONFIG_CFG80211_WEXT=y
```

```
thomas@gentoo linux % grep MINSTREL /usr/src/linux/.config 

CONFIG_MAC80211_RC_MINSTREL=y 

CONFIG_MAC80211_RC_MINSTREL_HT=y 

# CONFIG_MAC80211_RC_MINSTREL_VHT is not set 

CONFIG_MAC80211_RC_DEFAULT_MINSTREL=y
```

```
thomas@gentoo linux % grep ATH9 /usr/src/linux/.config     

CONFIG_ATH9K_HW=m 

CONFIG_ATH9K_COMMON=m 

CONFIG_ATH9K_BTCOEX_SUPPORT=y 

CONFIG_ATH9K=m 

CONFIG_ATH9K_PCI=y 

# CONFIG_ATH9K_AHB is not set 

# CONFIG_ATH9K_DEBUGFS is not set 

# CONFIG_ATH9K_DYNACK is not set 

# CONFIG_ATH9K_WOW is not set 

# CONFIG_ATH9K_CHANNEL_CONTEXT is not set 

CONFIG_ATH9K_PCOEM=y 

# CONFIG_ATH9K_HTC is not set 

# CONFIG_ATH9K_HWRNG is not set
```

Do you know why i'm not able to have 802.11n? 

Thank you

Thomas

----------

## eccerr0r

802.11n is a signaling protocol.  It can run at 2.4GHz as well.

The webpage spec sheet you linked indicates that the adapter you have is not dual band, and thus cannot use the 5GHz frequencies.

I have many 802.11n devices that are restricted to the 2.4GHz due to the same problem.  They do get a boost from the signaling, but eat up a lot of the 2.4GHz band to do so.  Any other people around you could chew up on that limited bandwidth.

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## Tom_

@eccerr0r, thank you for your reply. 

You're right about this 2.4 Ghz limit but according to the specs, it should be able to run at 300mbps.

Yesterday afternoon, I moved the AP very close to this computer but i didn't get anything better than 54 mpbs.  

When you said "a lot of the 2.4GHz band", did you mean configuring a 40mhz bandwidth instead of a 20mhz  bandwidth? 

Is there anything i should do to get more than 54mbps ? 

Thomas

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## eccerr0r

Remember that the channels overlap when using wide bands.  Unless you're out in an RF quiet area, there's no guarantee that you will get full bandwidth.

What if you move closer to the AP?  Can you get faster speeds that way?

I think what you see is pretty much what you get (it did try to get 57Mbit link which is at least better than 802.11g), not much you can configure due to the FCC anyway.

----------

