We propose two methods for improving the stability of communication in ad hoc wireless networks - firstly, the selection of reliable neighbors for data relay based on monitoring signal strength variations and secondly, the synchronous update of routing tables. These methods were designed to overcome problems observed in recent large testbed experiments. We show the dramatic improvement in stability and reduction of packet error rate which was achieved when we introduced these methods to an implementation of the OLSR routing protocol. Specifically we evaluated performance in a 50-node ad hoc wireless network, and showed a reduction in the packet error rate from 12% to less than 1