It's happened to me pretty regularly for the past six years, and was the main reason I switched to Davis.
I would lose comm for a couple of days at a time (unless I climbed the roof and did a manual reset).
For what it's worth, when I installed the Davis station (5 months ago), I also moved the computer room/consoles.
Since then the Oregon Scientific seems *better*, but it still loses communications. (The Davis has had no problems).
I thought my problem might have been bad equipment and I ended up purchasing two "spares" over the years. I think it may have to do with some sort of interference I'm generating at the house, like, if I turn the microwave on at the exact moment it's transmitting, I would lose comm.
As another data point, even when wind speed was not functioning, direction worked fine.
If it turns out that you are having an actual, physical problem, I've got a "parts" anemometer that spins kinda rough (bearings?), that you're welcome to for the price of shipping.
-Joe