I have two CC2510-based devices communicating with each other using GFSK at 250 kBps. I'm not testing in an anechoic chamber, but the environment is fairly RF-quiet. The RSSI values are about -45 dBm. Bit error rates are decent but not great considering high RSSI--1% or so. When I enable Manchester, the error rate drops noticeably. Is there an explanation for this? I would rather not drop my throughput by a factor of two, and would like to know if there is another way to improve the error rate (mod rate, mod type, etc).