How to connect ATT Uverse to HDTV that only has a F Style Coax Connection?

I have an RCA SPS36123 which is an under the cabinet HDTV. It only has a coax cable connection, so if I set the tuner for AIR it looks for HDTV channels, but I need it to be on old style channel 3, so I tried cable, but it still didnt see channel 3. Any suggestions?|||Sorry to tell you this, but you don't have HDTV. Nowhere does the manual for your RCA unit says that it is HDTV. It is just a SDTV with a wide screen and has an integrated DVD. The unit does have an ATSC tuner though. However this is worthless to you because you are not getting the signal off the air using an antenna, i.e. you are using a Set-Top-Box (STB) from AT%26amp;T Uverse. You can get an ATSC RF modulator, but that would be more expensive than your RCA TV unit. The best that you can do is to use a Standard Definition RF modulator from the AT%26amp;T STB using the yellow RCA composite video out and Red+White audio and the RF modulator will convert it to analog RF signal on Channel 3 or Channel 4.