What kind of cable must be used with an outdoor antenna (RG-59, RG-6, RG-6 Quad Shield )?

Here in the Los Angeles area, all of the local channels stations are transmitted in the UHF band, channels 14 - 69 and their sub-channels. All 3 coax cables will probably work, but I went with the RG-6U cable because of my 75 ft. run from the antenna to the DTV box. Not to mention the fact that I am 75 miles away from the transmitting towers. I use a high gain bow tie antenna with a preamp. My antenna is on a 30 ft. telescoping mast with a rotor. I receive around 40 channels and their sub-channels. Reception is excellent.