... Do you know if I use a longer USB cable will I lose any signal strength???.
I can't tell you what will happen in your setup, but I can tell you my experiences.
I am currently using approximately 16 feet of USB cable (6ft cable + 10 ft extension), and I haven't had any issues.
However, a few months back I had tried using several different "extenders", the type that are split with a CAT5 cable between them. I don't know if it was my house, or bad karma, but those things caused all sorts of problems. They were VERY prone to picking up stray electrical noise, and would reset themselves at the drop of a hat. Repeated resetting of the USB connection caused the CM15A to "go crazy," and lock up (resetting the flags to a "known error" state - with some of them on, and some of them off).
I REALLY don't recommend using a USB-over-CAT5 extender if you plan on keeping the CM15A connected all the time.
As I recall, the "official" maximum length for USB connections is about 16 feet. You can use powered hubs to extend that, but don't overdo it.
A better bet is to use a regular extension cord to bring the "outlet" closer to the CM15A, and keep the CM15A physically closer to the PC.
In my case, I took a 75-foot extension cord, and ran it between the outlet on my XTB-IIR (which is at one end of the house, next to the breaker box), and my computer area (all the way at the other end of the house). I haven't had any issues with this setup.