I'm a bit stumped with a wireless problem, perhaps someone
has suggestions of how to proceed.

  EXECUTIVE SUMMARY: machine can detect the card just fine,
sees wireless networks at work, but completely fails to find
the home wireless network. Other machines find the home
network, as does this machine when it's running Windows.

--------------------
  Fresh install of Ubuntu 7.04 on an Inspiron 640m,
Broadcom Dell Wireless 1390 WLAN card in 802.11b/g mode.
(So say lspci and iwconfig.)

   Installed bcm43xx-fwcutter package according to instructions:
this asks whether you want to download the appropriate firmware,
then automatically unpacks it and puts in the right place. Whee.

  So far, so good. Drivers get installed, OS can see the
wireless card, when I'm in my office nm-applet actually detects
several different wireless networks (none of which I have
permission to log onto). When I'm at home and boot the
machine into Vista (boo, hiss) instead, it automatically detects my home
wireless network (WEP, running from a 2Wire HomePortal 1700HW box) and
logs in once I give the WEP key.

  However ... on the Ubuntu side, it's just not seeing
the network. The network-manager applet doesn't
see any wireless networks; I can manually enter the
ESSID and hex key in "Connect to other wireless networks",
and I get an icon, but no connection. "iwlist scanning" gives "No scan
results" for eth1. I've tried using iwconfig to set everything
manually -- essid, key, channel, access point -- but
nothing seems to make a difference. (iwconfig lists
the frequency as 2.484 GHz, my router says it's running
at 2.437 GHz [channel 6], I can switch the channel
manually to 6 with iwconfig but it seems to drop
back to 2.484 every time.)

  The weirdest thing is that I just now logged into
the router (it has a fairly friendly web interface)
and noticed for the first time that it actually
picked up the machine AT SOME POINT -- it has the correct
MAC address -- ???

   I will take the machine back to work and try it out
with some other networks; I suspect it will be OK
there and that there is some specific issue with my home
network (which works just fine with the Windows boxes
in the house and with the old laptop, which is running
Ubuntu 6.06). I will also try installing other wireless
diagnostic stuff (wifi-radar, wlassistant) and see if
it gives me any clues.

  Sorry for too-much-information, but I'm pretty well
stumped now.

  Once I get this solved I may come back and ask whether
there's a way to get my home router running WPA instead ...

   cheers
     Ben Bolker