Original sentence: During big contest weekends a large fraction of the available radio frequencies on the HF bands are occupied by contesters, and many of them object to non-contesters attempting to use "their" frequency until the contest is over.The result is that non-contesters as a group feel that they are left without adequate spectrum in which to operate
Edited sentence: Nevertheless, some non-contesters complain that during big contest weekends, all or almost all available radio frequencies on the HF bands are occupied by contesters, and even though any individual contester has as much right to use a frequency as a non-contester, the result is that non-contesters as a group feel that they are left without adequate spectrum in which to operate.Some contend that these suggested alternatives do not meet the needs of those displaced by contest activity.Stations operating in close proximity to one another may create interference