I recently purchased and installed a channelmaster 4228 UHF antenna. With it I can get a good signal from a Shreveport station about 60 miles away (ABC). The AntennaWeb site says this requires a "blue" antenna type from my location. There is a second station transmitting from the same location (CBS) but the AntennaWeb site says this requires a "violet" antenna. My set-top box does not pick up a signal from this transmitter. I know that I could improve my reception by either raising my antenna and/or installing a preamp. I was prepared to do this if I couldn't get a strong enough signal but I'm not sure what to do now that I'm getting a strong signal from one and an unknown strength from the other. Does raising the antenna still make sense since my line of sight is OK to this location? Should I try the preamp? Any suggestion will be greatly appreciated.