How can a group of distributed secondary users make rendezvous on one among a set of available channels, whose exact content is a priori unknown to the participants? Let us assume that secondary users scan the set of channels, attempting to make rendezvous with each other. Each user has several radios that are concurrently used to achieve rendezvous. We propose two rendezvous algorithms for users equipped with several radios each. We study in detail the multiple user case and the asymmetric case, where the users have different but overlapping channel sets. The performance of the algorithms are analyzed and evaluated through simulation. Equations modeling the worst case performance and expected performance are developed