I have a curious question for you: If you are often without internet for several months at a time and cannot judge when/if you'll return, what are you gaining out of joining a coven? What is that coven gaining out of accepting you as a member?
The point of covens is multi-purpose; to learn, to share, to grow, and to socialize. If you are off the site for that much time at random intervals, are you really benefitting from being a member of a coven? Can you really say you are partcipating in that coven?
This isn't meant to shame you or anything like that (although I know it could be read that way if you so desired), but rather to make you think about why you want/like to be a member of a coven. If it's something that you can get equally without being a coven member, you might consider staying out of covens or joining a coven like Spell Casters. The system doesn't knock Council members out of the coven whenever they haven't been active for months at a time, so you would remain safely in Spell Casters. Or you could always try to convince a p/p that you are an awesome enough member when you are around to hold your account as Council in between your inactive periods.