What will make a stock radio randomly turn off...

So...both on my old CB (cobra 19ultra 3) and now on my Galaxy 979F...the CB will sometimes randomly cut off....after a while, I can turn it back on again...but it's really annoying. My SWR is 1.1 on ch1, and 1.3 on Ch 40. I'm running a NMO Wilson 5000 antenna. My power leads are going straight from my battery on both positive and negative.

Any ideas?