These are very useful in caravans and much better than cell phones at short distances in my experience. In areas where there are a lot of users is beneficial to use the sub-channels. Mine have 18 channels and 38 sub channels that is over 600 different frequencies I doubt there will be 600 different user groups. I suggest you go out and play with them to get a better feel for the capabilities. <img src="/images/graemlins/grin.gif" alt="" />