Wifi unstable - Precision M3800, Ubuntu 14.04 LTS, Intel 7260

Somebody recommended that this was the best place to get specialist advice on my laptop problem.

Sometimes my laptop is able to connect to my router. Much of the time, it just does the "connecting" animation for a while, then fails to connect. Suspending/resuming always causes problems; will usually fail to connect after a resume.

I have noticed that it connects easily to an Android tether, and to Starbucks WIFI. But it doesn't work so well at home.

My M3800 came with Ubuntu pre-installed but I overwrote it, installed Win7 and then put Ubuntu back on a separate partition. Unfortunately I forgot to make a Dell Recovery Stick before I formatted. I installed using the stock ISO from the Ubuntu website. Could it be a driver/firmware issue? Or is it more likely my router? I have heard that these cards can have trouble with 802.11N, so I'm currently on B+G combo - no significant improvement.

Thanks and best wishes,

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