First off 281 is a Free Preview Channel, which is supposed to be ESPNU, this was taken off at the beginning of the month, don' know why.
Second Altitude is an RSN HD channel, if you do not have a Vip HD receiver nor are in the region that Altitude is assigned to, you will not see it. Do you receiver channel 410? If not, you should not see 360.
Update, Veria will be in free preview on 281, but not until Wed. I didn't research the channel, just what is currently uplinked, which is still ESPNU for some reason. Also, Altitude HD should be an rsn for Colorado.