# Ubiquiti Atheros Wifi ... weak signal??

## pvangarde

Hello.

I just received my Ubiquiti wifi card with external antenna (http://www.ubnt.com/super_range_cardbus.php4). This is the spec for it:

Wireless Chipset Atheros 5004

WPA, WPA2, AES-CCM & TKIP Encryption, 802.1x, 64/128/152bit WEP

IEEE 802.11a/b/g with CCK/OFDM at BPSK/QPSK/16QAM/64QAM

32-bit Cardbus Type II

-40C to +80C (extended temp version up to +95C)

6Mbps, 9Mbps, 12Mbps, 24Mbps, 36Mbps, 48Mbps. 54Mbps

See page for more details. I emerged madwifi-ng and the card gets very low signals. My wireless router sits 1 foot away from the laptop and I get 50-60%. This is not a card-specific problem, I get 100% signal strength in windoze  :Sad: .

Should I be installing madwifiold driver? I also can't change card mode to Monitor, I get an error. Maybe I don't have some extension in the kernel, or the correct package installed. I'm running suspend2 2.6.21 x86.

Thanks for the input.

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## didymos

OK, where are you getting the linux percentage from? I'm more interested in what iwconfig reports for Signal and Noise level, in addition to Link Quality. Also, reported data rate. On the windows side, what is reporting the percentage? If Windows itself, what's it's qualitative description: i.e., Good, Low, etc.  If you have Windows scan for APs, is the number shown there different?  Lastly, are there connection stability issues on Linux but not Windows, and is throughput on Linux worse than Windows?

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## pvangarde

 *didymos wrote:*   

> OK, where are you getting the linux percentage from? I'm more interested in what iwconfig reports for Signal and Noise level, in addition to Link Quality. Also, reported data rate. On the windows side, what is reporting the percentage? If Windows itself, what's it's qualitative description: i.e., Good, Low, etc.  If you have Windows scan for APs, is the number shown there different?  Lastly, are there connection stability issues on Linux but not Windows, and is throughput on Linux worse than Windows?

 

I will provide all the detailed information after several hours. 

Generally: I get my percentage from iwconfig, which is a fraction  (58/94). 

On Windows, I  get 5 bars (Excellent) and I also use a piece of supplied 'client' software that gives me extra stats on the connection. That's where I can see 100% after establishing connection (and although that sounds a little too much, remember the router is located a few feet away from the machine). Before establishing it, I can see a slightly lower percentage, but I've noticed the same with my old wireless card, so this is either something common, or its my router.

I believe the number of APs is the same in windows/linux, the link quality is the difference. Again, I will post all the revelant info in several hours. Thank you.

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## pvangarde

dmesg:

```

Yenta: CardBus bridge found at 0000:06:04.0 [103c:30a4]

Yenta: Enabling burst memory read transactions

Yenta: Using INTVAL to route CSC interrupts to PCI

Yenta: Routing CardBus interrupts to ISA

Yenta TI: socket 0000:06:04.0, mfunc 0x00a61b22, devctl 0x64

Yenta: ISA IRQ mask 0x0cf8, PCI irq 16

Socket status: 30000820

pcmcia: parent PCI bridge I/O window: 0xa000 - 0xafff

cs: IO port probe 0xa000-0xafff: clean.

pcmcia: parent PCI bridge Memory window: 0xc0200000 - 0xc02fffff

pcmcia: parent PCI bridge Memory window: 0x60000000 - 0x63ffffff

Device driver pcmcia_socket0 lacks bus and class support for being resumed.

pccard: CardBus card inserted into slot 0

ath_hal: module license 'Proprietary' taints kernel.

ath_hal: 0.9.18.0 (AR5210, AR5211, AR5212, RF5111, RF5112, RF2413, RF5413)

wlan: 0.8.4.2 (0.9.3.1)

ath_pci: 0.9.4.5 (0.9.3.1)

PCI: Enabling device 0000:07:00.0 (0000 -> 0002)

ACPI: PCI Interrupt 0000:07:00.0[A] -> GSI 20 (level, low) -> IRQ 16

cs: IO port probe 0x100-0x3af: clean.

cs: IO port probe 0x3e0-0x4ff: clean.

cs: IO port probe 0x820-0x8ff: clean.

cs: IO port probe 0xc00-0xcf7: excluding 0xc00-0xc07 0xc10-0xc17 0xc50-0xc57 0xc68-0xc6f 0xcd0-0xcdf

cs: IO port probe 0xa00-0xaff: clean.

ath_rate_sample: 1.2 (0.9.3.1)

Device driver wifi0 lacks bus and class support for being resumed.

wifi0: 11a rates: 6Mbps 9Mbps 12Mbps 18Mbps 24Mbps 36Mbps 48Mbps 54Mbps

wifi0: 11b rates: 1Mbps 2Mbps 5.5Mbps 11Mbps

wifi0: 11g rates: 1Mbps 2Mbps 5.5Mbps 11Mbps 6Mbps 9Mbps 12Mbps 18Mbps 24Mbps 36Mbps 48Mbps 54Mbps

wifi0: turboA rates: 6Mbps 9Mbps 12Mbps 18Mbps 24Mbps 36Mbps 48Mbps 54Mbps

wifi0: turboG rates: 6Mbps 12Mbps 18Mbps 24Mbps 36Mbps 48Mbps 54Mbps

wifi0: H/W encryption support: WEP AES AES_CCM TKIP

wifi0: mac 5.9 phy 4.3 radio 3.6

wifi0: Use hw queue 1 for WME_AC_BE traffic

wifi0: Use hw queue 0 for WME_AC_BK traffic

wifi0: Use hw queue 2 for WME_AC_VI traffic

wifi0: Use hw queue 3 for WME_AC_VO traffic

wifi0: Use hw queue 8 for CAB traffic

wifi0: Use hw queue 9 for beacons

Device driver ath0 lacks bus and class support for being resumed.

wifi0: Atheros 5212: mem=0x64000000, irq=16

pcmcia: Detected deprecated PCMCIA ioctl usage from process: cardmgr.

pcmcia: This interface will soon be removed from the kernel; please expect breakage unless you upgrade to new tools.

pcmcia: see http://www.kernel.org/pub/linux/utils/kernel/pcmcia/pcmcia.html for details.

```

OK, the only things I see: it says Atheros 5212. The spec for my card said 5004. cardmgr deprecation.

iwconfig

```

ath0    IEEE 802.11g  ESSID:"xxxxxxx"  Nickname:""

          Mode:Managed  Frequency:2.427 GHz  Access Point: 00:11:50:xx:xx:xx  

          Bit Rate:54 Mb/s   Tx-Power:16 dBm   Sensitivity=0/3  

          Retry:off   RTS thr:off   Fragment thr:off

          Encryption key:xxxxxxx   Security mode:restricted

          Power Management:off

          Link Quality=55/94  Signal level=-40 dBm  Noise level=-95 dBm

          Rx invalid nwid:221  Rx invalid crypt:0  Rx invalid frag:0

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

```

The security mode should be open I think, so I changed it. (no difference). Why is sensitivity set to 0?

Throughput  is good from I can see, I didn't actually test the network, but I downloaded openoffice with 600 K/s, which is about what I expect.

I'm using NetworkManager to connect to networks by the way.

iwlist scan

```

lo        Interface doesn't support scanning.

eth0      Interface doesn't support scanning.

sit0      Interface doesn't support scanning.

wifi0     Interface doesn't support scanning.

ath0      Interface doesn't support scanning : Network is down

```

To avoid the output, I brought the device down, normally I get scan results...

Also, this is a 300 mW card, however:

iwlist ath0 tx

ath0 8 available transmit-powers :

0 dBm (1 mW)

7 dBm (5 mW)

9 dBm (7 mW)

11 dBm (12 mW)

13 dBm (19 mW)

15 dBm (31 mW)

17 dBm (50 mW)

19 dBm (79 mW)

Current Tx-Power=16 dBm (39 mW)

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## didymos

OK, you're fine then.  You're at 54Mbps.  In iwconfig, the top number of link quality matters most, and that's 55. Now, the main thing to realize is that every card and driver are basically free to use any number of different data sources to calculate strength/quality and report the RSSI (Received Signal Strength Indicator), which is only intended to be a relative, rough measure.  The scale for it isn't even standardized.  It always starts at 0, but vendors can report up to 255 as the "maximum maximum".  So, one card's scale could go from 0 to 80, while another goes from 0 to 100, and both of them may be using different ways of coming up with those numbers.  Then you've got Windows, which has it's own way of coming up with the whole bars display and the "Low", "Good", "Excellent" scale by interpreting whatever the Windows driver is saying.  This is the best explanation of that I could find:

```

Windows Signal Level    Signal to Noise Ratio   Data Rates

Excellent               26 dBm and above        11Mpbs and up

Very Good               25dBm to 21dBm          11Mpbs

Good                    20dBm to 16dBm          11Mpbs

Low                     15dBm to 11dBm          11Mpbs

Very Low                10dBm to 8dBm           5.5Mbps

Very Low                8dBm to 6dBm            2Mbps

Very Low                6 dBm and under         1Mbps

```

(from here: http://www.osuweb.net/wireless/faqs.html#whydoesmysignalstrengthsaylow)

How this has changed to account for newer cards with 11g and stuff like SuperG, who knows? Anyway: So, what's the SNR? Well, it's the top number in link quality when using iwconfig, and it's arrived at by subtracting Signal level from Noise Level.  In other words, your 55/94 "translates" to 100% (Excellent) in Windows. The bottom number is just the minimum possible Signal Level at which the madwifi-ng drivers might still be able to operate.  What matters is connection stability and data rate.  See these docs as well:

http://madwifi.org/wiki/UserDocs/RSSI

http://madwifi.org/wiki/FAQ/SignalTooStrong

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## pvangarde

Thanks a lot for the explanation and links. The Signal Strength link talked about saturation from being too close to the AP and getting rates of 600 KB/s. That's the rate I've been getting.. funny.

What I don't understand is why NetworkManager reports my signal strength under 60% and sometimes even 11% and 20%.  

Thanks again, I feel much better.

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## didymos

Network manager may be using some other method to calculate strength; you'd have to look at the code. Also, signal strength can bounce around a bit, and depending on how fine-grained the time periods are w/NM, it could jump quite a lot whenever some stray signal or noise source interferes with the channel you're on. Mainly, you just want to be able to move data as fast as it comes in from the net, unless you're doing a whole lot of file transfers within a LAN, in which case I'd say just buy a couple Gigibit Ethernet NICs and some cable, because even operating perfectly and with something like SuperG enabled, the cheap wired NIC will still blow the wifi card away.

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