Default [Q] LTE connectivity issues with ReVolt

So I recently flashled one of the CM11 nightlies and noticed that the LTE was not connecting on my Galaxy S4. I thought this may just be an issue with CM 11 since it's still so new so I flashed ReVolt instead and I'm having a similar issue. This time, the LTE connects but it takes forever to do so and even when it does, the signal is abysmal. The speeds are not LTE speeds either. Just to be clear, I actually did a complete unroot and restore to stock before flashing ReVolt and I wiped cache, dalvik, and system before flashing. I also wiped cache and dalvik after flashing.

I realize that ReVolt is based on CM but since it's based on CM 10 (I think) I thought the LTE would be working fine, as I used CM 10 before and had great LTE speeds. Do I need to do something different to get my original speeds back? I've heard of flashing a new radio or modem, but I wouldn't know which one to flash or even if that's what is causing the problem. Any help is appreciated. Thank you!