In this letter, a problem related to the behavior of WLAN 802.11 b network cards when working in the ad hoc mode is described. This behavior was noticed during experimental evaluation of an ad hoc network that was using the AODV (ad hoc On-demand Distance Vector) routing protocol. The observed problem affects the neighbor detection algorithm of the AODV routing protocol and has a deteriorating impact on performance of ad hoc networks that use this protocol. An improvement of the neighbor detection algorithm based on the differentiation of good and bad neighbors using signal to noise ratio (SNR) value is proposed, described and experimentally verified.