It is not clear where you are losing the connection from in your posting.
Are you losing it at the modem. Is it failing to transmit from the router. Or is it being lost at the computers.
The latter is pretty common. It almost always ends up being a problem with what you are using to configure the adapters. Are you using Windows or the Belkin utility?
If it is the modem router try changing the channel frequency.
Also download NetStumbler and check you are not competing with other networks on the same channel.