Per Radio Shack support documentation @
http://support.radioshack.com/suppor...oc44/44032.htm The VHF high band gain of your existing antenna (in good condition) is 8.2 dB and the UHF gain is 9.6 dB (Not clear if they are using dBd or dBi
)
If you were to replace the RS antenna with a Antennas Direct 91XG
http://www.solidsignal.com/pview.asp...0Antennas&sku= mounted 4' to 6' above an Antennacraft Y10-7-13
http://manuals.solidsignal.com/Y10-7-13.pdf You would in theory get a 1.2 dB improvement for channels 7 through 13 and 7.1 dB improvement for the UHF band.
That means that you could see some improvement in the picture quality on the analog translators and you could have a possibility of receiving KTTV (Fox) on VHF 11. Slightly lower expectations for KABC, but still possible. This combination of antennas may not do well receiving channel 6 KRPE-LP.
A quality rotator is needed (
http://forum.tvfool.com/showthread.php?t=1058 and a preamp such as the CM8275 or CM7777 either of which have separate inputs for UHF and VHF antennas.
Your TVF report indicates an antenna height of 40'. Do you have an existing tower or are you on a multistory building?