Problem with wireless network after installation of mobile broadband dongle
I have a Acer Aspire running dual boot Ubuntu 9.10 and Vista. Although it has an Atheros wireless card (AR5001 according to linux, AR5007 according to Vista) until recently I didn't have any apparent problems with it.
I installed a ZTE MF112 Mobile Broadband Dongle. Now I am experiencing great difficulty in communicating with my wireless router (with both LAN and WAN traffic). Connecting to the network in the first place appears to happen quite smoothly and my computer obtains a DHCP IP address. However the ping response times are measurable in seconds rather than the milliseconds I would expect, and any traffic across the network crawls, or just times out and fails.
I do not believe it is the router at fault as two laptops, both also with Ubuntu, can connect to it fine and swapping it out for another router does not fix the problem either. Also there is no problem connecting from Vista.
I suspect that installing the dongle has altered something which has made the bugs in the wireless card/drivers apparent and that's where I need some help.
How do I go about further troubleshooting my network?
Thanks in advance,