Are you seeing cat sign? There has to be cats there to call them in. Bobcats like thicker cover, brushy draws, areas with large brush piles and such. I have called them both ways with continuous calling and with breaks. I use continuous if I specifically am trying for a bobcat, but I frequently change the sound volume and may also change the sound itself, just going from one sound to another. If I am calling coyotes I use breaks but have had bobcats come in then too. If you are hunting at night with lights you should keep scanning until you see eyes.