I don't know this is an Ubuntu issue because I have an Atheros chipset and
have never experienced like what you describe and if it was common you can
be assured that you would not have trouble finding others with the same
problem. The fact that you can't suggests that it is likely something else.

The fact that something works in another environment may or may not be
useful information. Things work or not for various reasons. There are
different drivers, different network managers, etc. There may even be
something in your home that interferes with the connection and it could be
coincidental based on time of day and not OS. It could be a driver issue
that has nothing to do with Ubuntu (they don't make drivers). It could be a
bad copy of Ubuntu. There is no way to know based on what you have written.
We should not ignore the fact that it could be a bug in Lucid, but that is
not necessarily the case.

To troubleshoot, I would look at trying any of these things:

Remove wicd and try network manager (that could pin it down to a network
manager issue). Try a different desktop environment such as KDE by
installing kubuntu-desktop in Synaptic (that could pin it down to driver as
they would be the same). You will need to login into KDE at login using the
session manager. Neither of these involves much effort and is reversible.
You could install madwifi divers (in the repos). You could add backports to
Lucid which would give you access to newer applications and drivers. You
could look at blacklisting or changing your settings files.

https://help.ubuntu.com/community/UbuntuBackports

If nothing works, then try the latest version 10.10 Maverick which uses a
newer kernel. Finally you could try a variant of Ubuntu such as Mint rather
than go outside the family by using Mandriva which is a fine distribution,
but hardly the same.

Not Really a problem with the OS. I have the same problem using my MiFi
on the fringe. I have no problem in town using free Wifi at the Library
indicating that it is more likely a router problem. This may be signal
strength forcing the disconnect.

Rebooting is not necessary that is a Windows thing not Linux. If a
program locks up in Windows you have no choice but to reboot. In Linux
shut down the program and restart it is the fix but have not had to do
that to get the wifi working again as of yet.

People who have trouble connecting at the Library are directed come into
my class for a fix. They usually get told to use Linux for all the
benefits, and I install it for them.

What springs to mind here is a Linux incompatible Wi-Fi adapter and
the only way to be sure is to test with a different one and see if
that has the same sort of issues. I've had Wi-Fi working perfectly, as
have many others, so it does work with a compatible adapter. FWIW the
ZyXel USB Wi-Fi adapter is 'plug and go' so perhaps it might be worth
getting one of those to verify whether batting your head against this
particular wall isn't going to get you anywhere ?

I don't know how much help this is going to be, but my last two updated versions
do the same. I have to boot into an older version to stay connected. I've been
frustrated in searching for an answer, myself. Do you have an older, stable
version you can select?

My wireless network seems to be working properly now, it has been working
without any deconnection during several hours and after been rebooted several
times. I cannot explain but only write what I have done.
While I was still connected by "wicd" I quickly installed the basic
"network-manager" from "System" "Administration" "Synaptic packets manager" and
by the same way uninstalled "wicd". I waited around one hour before
rebooting.The wireless network opened before by "wicd"
did not close anymore as "wicd" had totally been removed (configuration files
included) from the computer, my wireless connection was rock steady for the
first time.
I then rebooted to check the newly installed "network-manager". No joy, it did
not connect. I made a few "sudo stop network-manager" and "sudo start
network-manager" without seeing any network-applet in the tray.
I rebooted again and without any explanation the network-applet was in the tray,
it was trying to connect, it did it and has been since that time rock steady. I
did a few reboots yesterday and also this morning with the same nice result. Now
my /var/log/messages and /var/log/syslog show nothing wrong.
I then cleaned all these files which had been edited during my attempts to get
the thing working, like /etc/network/interfaces, which is now the very basic
auto lo
iface lo inet loopback
without anything else.
I also did not try to add any other program like "wifi radar" as I did before
and I won't try to use again "wicd" which may have been responsible for these
problems, I am not sure but I do not want to change again a system which is
currently working properly.