Some of my rides are for hours with video recording and radio. For that reason, I usually have an external battery pack connected by USB cable to the 10C or EVO mounted on my helmet. I notice that with the external battery pack connected, there is poor reception FM radio reception and static. Without the external battery disconnected, there is little or none (RFI or EMI interference?). Have tried different USB cables and external batteries. QUESTION: Is anyone else experiencing this issue, and have you found a solution. I am using a Sena USB cable. Recently purchased clip-on Ferrite chokes to attach to the cable but haven't tried them yet.  Thanks.