I've been using a Jetpack 5510L for several months. While it only gets about a 35% signal it's been very adequate for me with between anywhere beteeen 5 and 20 Mbps download speeds. A few days ago it dropped to around .25Mbps or less even though the signal strength is the same. Could there be a problem with the tower(s) I get the signal from? There was some lightning storms for a few days. Could the device itself have become faulty (how would I tell)? I've tried resetting, removing the sim card for a bit and many power off/on cycles but the speed hasn't improved.