We run 2 cars with early Spektum via 3000 recievers (sanwa super exzes module), Novak GTB's non spread, one has a power cap, other not, but no problems last 18 months. I know this is no help, but your stuff should work.

Just thinking with 27/40mhz tackle we would be moving it around in the car, away from battery cables......somehow I just expect specky to work.