One device is putting out RF interference. I had the exact thing happen with a preamp once, only when it received an IR signal - then it went ballistic.

Currently cable boxes and blu ray players are the most likely culprits. Move your 260 around and away from the components for test.

...and fold the antenna all the way down to see if I am right. The remote has plenty of output to hit it. If its interference the antenna down trick may get you a measure of reliability.