On a computer that is running Microsoft Windows XP Professional or Windows XP Home Edition with a wireless connection enabled, the Wireless Network Connection dialog box does not show the real-time signal strength for all the currently available wireless network connections. The signal strengths are not actively updated.
This behavior is by design. This behavior avoids unnecessary overhead in Windows XP.
The Wireless Network Connection dialog box is not designed to keep the signal strength for all the currently available wireless networks up to date. To keep these signal strengths up to date would create an adverse effect on the wireless radio spectrum.
To see the real-time signal strength of the wireless network connection that is currently in use, see the Wireless Network Connection Status dialog box. This dialog box is actively updated.
wireless network connection signal strength 802.11b 802.11g