Yes, the Sentinel is 10 years old and if current rumors are to be believed then it may be susceptible to jamming and apparently has no onboard self destruct features. Radio jamming and GPS jamming is not overly complex... you can buy the parts for a fairly effective radio jammer at Radio Shack for $50. Personally, I'll wait until more verifiable info is learned before making a shit-ton of premature guesses on what happened. What I won't do is make silly comments like the one below your post about Iran bringing down all US drones. That's like saying "OMG!!11! SAMs can shoot aircraft out of the sky, we better not use them!!1!" Uh, no... we still use aircraft and yeah, one might occasionally be downed. You adjust accordingly, which is exactly what US military planners in this area are doing as we speak regarding the drone.
Some of the attitude in this thread is funny though, like a joyous celebration of embarrassment for the US military. Yep, it's a little embarrassing and should rightly be fixed. At the same time, proper perspective helps as well. We could be conducting a large operation against a formidable enemy where we have a U2, Ep3Orion, JSTARS, AWACS, Rivet Joint, multiple UAVs, perhaps an MC-12, and a couple tankers to keep 'em gassed all up at the same time. This is a monumental amount of activity that requires immense coordination as C2, ISR, Comm, and other areas combine to gather and deny info accordingly... it's like a dozen orchestras operating as one and not a shot has been fired. Now throw in your wild weasels, some CAS, some strike, and some superiority fighters to protect the others and you've just doubled those orchestras to 24 and the amount of sheer money, power and capability that's linked and laying down some magnificent pain is awe-inspiring. So I guess the moral of the story is, yeah, it's a bit embarrassing when the wiper blade on the Bugatti Veyron goes bad... but it's still a fucking Bugatti Veyron.