Coaxial A/B Switch


I bought a Samsung UN22D5000 two days ago to replace a Samsung LNT1953H TV/Computer monitor. The older one has two F connectors for coaxial cable, but the newer one has only one. Because I like to have both an over the air antenna and DISH network, I need twin coaxial cables. I bought a cheap Philips A/B this weekend and found it to be very lossy. Some much so that when I connected either cable by itself everything was fine, but simply adding that switch and a short 3 foot run of RG-6 the over the air channels pixelate. I suppose it could be the patch cable or the switch. At any rate I am know wondering if all A/B switches are created equally, or if some are more lossy than others. And, if that is the case, what are some better switches that won't lose as much signal?
Many find that they can connect the Satellite receiver to an A/V input using component, S-video, composite video or HDMI and use the TV input switcher to go between off air and the A/V input.