I often have trouble connecting to wifi with my MacBook Pro. To help identify the problem, I was wondering if there were any tools for measuring wireless signal strength.
If you're just looking for a quick signal strength number, option-click on the AirPort icon in the menu bar. Under the connected network you will see several pieces of information:
RSSI is your signal strengh in dB. Higher (closer to 0) is better.
If you're looking for noise or the signal strength for multiple access points, I suggest checking out iStumbler:
You can get quite a bit of info from the command line, with the (well-hidden) airport utility. With the
-I flag it'll tell you about the current network:
$ /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -I agrCtlRSSI: -43 agrExtRSSI: 0 agrCtlNoise: -96 agrExtNoise: 0 state: running op mode: station lastTxRate: 130 maxRate: 130 lastAssocStatus: 0 802.11 auth: open link auth: wpa2-psk BSSID: 0:24:1:0a:42:93 SSID: My Wireless MCS: 15 channel: 5
-s will show more info about other visible networks:
$ /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -s SSID BSSID RSSI CHANNEL HT CC SECURITY (auth/unicast/group) My Wireless 00:24:01:fa:42:93 -44 5 Y -- WPA(PSK/TKIP,AES/TKIP) WPA2(PSK/TKIP,AES/TKIP) hobbit 00:15:05:19:8a:03 -86 7 N -- WEP My Wireless 00:24:01:ef:91:ab -75 3 Y -- WPA(PSK/AES,TKIP/TKIP) WPA2(PSK/AES,TKIP/TKIP)
It doesn't have a man page, but if you run it without any options it'll list its options.
If you find that your connection problems occur in the same location, you could use a tool like NetSpot that would let you visually see areas of low signal. NetSpot is free and available within the App Store.
See below for an example of how a map of your apartment's wifi signal could look.
Macworld reviewed Netspot and published a brief tutorial last year about how it could be used.
I typically use WiFi Explorer. Its newer than iStumbler and provides the following features:
- Easy-to-use, intuitive user interface.
- Graphical visualization of the wifi environment.
- Works with 802.11a, b, g and n wireless networks.
- Supports 2.4 GHz and 5 GHz frequency bands as well as 20 and 40 MHz channels.
- Signal quality estimations based on signal-to-noise ratio (SNR).
- Accurate conversion from dBm to percentage (%) for easier analysis and optimization.
- Export metrics and network details to CSV file format.
- Full screen mode (10.7 or above).
- Comprehensive help.
- Runs in Snow Leopard, Lion and Mountain Lion.
It's available in the Mac App store. It's priced at .99 cents. Developers are responsive to questions.