Airport Extreme 802.11n (4th Generation) vs. MBP 2006. The MBP is losing :(

Question

GRRRRRRRRR— I feel like this is a version of a problem I see repeated here endlessly, but none of the threads I see about it is quite the same, or fixes my problem.       We have a network with:
Airport Extreme 802.11n (4th generation), connected to DSL modem.  Firmware 7.5.2
MBP 2006, running OS 10.6.7 ****
MBP 2008, running OS 10.5.x
ipads, iphone, shared printer, drive, etc.
Everything works fine EXCEPT the MBP 2006.  It connects to the network, works for a while, and then after a certain amount of time (anywhere between a minute and several hours) it's dropped.  The menu bar still shows a connection and full signal, but there's no connection (TCP or afp) and when I launch the Aiport Utility, it just says that no base stations can be found.   The menu bar seems to be lying. Using the menu to turn Airport off and back on (or sleeping the laptop) works to reestablish the connection.
I do not have this problem with the MBP 2006 on other wireless networks (at work, or at my other home in another city).  Just with the Airport Extreme
I've tried changing the channels, disabling IPv6 on the laptop and on the Airport Extreme, setting up a manual DHCP address, and changing the setting for "radio mode" of the base station from Automatic to 802.11a/n - 802.11b/g/n.   I also read that there might be troubles with "mixed" networks with both 802.11g and 802.11n, so I upgraded the Airport card in my MBP 2006 to an AirPort Extreme 802.11 a/b/g/n, which made disk sharing much faster when it's working, but didn't put an end to the cut-outs
Hjalp?  Why does the Airport Extreme keep dropping my MBP 2006 (or vice versa)?  Are there other things I should be changing or disabling?

Answer 1

OK, two possible leads:
1) Using the AirPort Utility, I disabled 802.11n, setting the AirPort Extreme to b/g only.  This seemed to help— I didn't fall off the network all afternoon.  (Setting it to 'n' only did not work, unfortunately, or else that would have been better, since it would have let me take advantage of the faster speeds for Time Machine to the shared disk)
2) Soon thereafter, for seemingly independent reasons, we starting having trouble with our DSL connection.  We reset the AEBS to factor settings, which didn't solve the DSL problem (had to get a Windstream technician out for that), but since that reset, I've been connected with 802.11a and the MBP hasn't fallen off the wireless network once.
We'll see how it holds up, but for now, the recommendation seems to be first to reset the AEBS settings to factory default, and then try disabling 802.11n...