When connection suceeded though, it did strange things. Chief amongst these was registering either an untrue 54Mbps speed (but still the usual 1 bar signal) a few seconds before disconnection, or an untrue excellent signal strength likewise a few seconds before disconnection.
I think that this might be down to a combination of sampling frequency and Fallback data transfer rates, aka Adaptive Rate Selection.
The fallback rates are:
- 802.11b: 11, 5.5, 2, 1 Mbps, auto-fallback;
- 802.11g(Normal mode): 54, 48, 36, 24, 18, 12, 9, 6 Mbps, auto-fallback.
Note that a .b / .g wifi access point actually has a separate modulation mechanism for .b and .g - a "b" client" on a "g" network will significantly reduce the throughput on the .g network.
It looks as if your wifi card was set to 802.11b/g, and since it connected reliably at 2 / 5.5 Mbps it had "locked on" to an 802.11b signal (this could either be because the wifi router was .b only, or both .b and .g, and had reduced to .b because of poor signal strength).
If the signal was lost, your card might then have tried to establish a .g connection, which would "start" at 54 Mbps and drop to nothing when the signal became too poor.
The (very approximate) graphical indication of wifi connection speed & strength samples and displays at fairly long intervals compared to the actual re-try attempts going on behind the scenes, so perhaps just showed the beginning (strong signal, 54Mbps) and / or end of the process (no signal, no connection).
SD