Is the weather changing, or your location, or maybe a tree close to your window thats moving blocking signal? It sounds funny but a lot of things interact with a wireless signal. Any electronic which emits a wireless signal can interfere with your network connection. I never seem to have any problems unless its when I am receiving data on my phone as well as trying to use my Laptop connected to the Barnacle WIFI. Like if I get a phone call or a test message or a notification it will briefly lag. I don't know if that helps you at all. If you state which rom, baseband version, etc you have I'm sure someone who knows more than I do can help you better by pinpointing the specific cause.
Edit: Try to change your wireless channel in your barnacle settings. See if your computer picks up the other channel better, just remember the original channel so you can always default it back, there is no auto default selection.