spektrum, spektrum, spektrum, need I say more. Tried everything on my SE , ring, grounding boom to frame, Deans antenna, Moving electronics around. NOTHING WORKED! Until I bought a DX-7 radio system. Now I can fly with confidince. I don't worry about when I'm gonna get a glitch. Doesn't happen. Some say that they have success with regular PPM or PCM gear. Maybe so but I pulled my hair out trying to fix mine. Just my opinion. Hated to see my 9C go, but now I don't miss it at all.