Your existing antenna is a notoriously poor performer in two important areas. First, it's omnidirectional design makes it incapable of rejecting multipath interference. Second, the VHF reception capability is very poor. Channel Master does not publish the specs, while the similar product from Antennacraft (
5MS921) has negative gain in all bands, in fact double digit negative gain in the VHF range.
I don't want to be discouraging, though perhaps I have been. I would like to encourage you to consider using an antenna system with positive gain and directional ability.
I suggest the Antennas Direct DB4e facing 110° (compass). This antenna should receive the UHF signals of KXJB, KVLY, WDAY & KMDE.
There are several VHF signals that can be received, WDAZ, KJRR & KFME. I would use an Antennacraft Y10713 for these. It will need to be mounted on a rotator or you'll need one antenna for each of the signals.
I would install an Antennas Direct PA-18 preamplifier on each antenna. If you choose to use a single rotating Y10713, you can combine the output of each amplifier, down stream of the power insertion block into a single coax. Combining UHF only with VHF only is easily done with a UVSJ.
If you want to avoid the rotator, a tuned combiner from
www.tinlee.com would be a possible solution. But you face a technical challenge when two signals are adjacent and from different directions, CH-7 & CH-8 in this case.
http://www.amazon.com/Antennas-Direc...&keywords=DB4e
http://www.antennacraft.net/Antennas/AntennasVHF.html
http://www.amazon.com/Antennas-Direc...keywords=PA-18
http://www.solidsignal.com/pview.asp...nna-%28UVSJ%29