Chamber Choir will include ap- From 1F built up other kinds of program ming (and ratings as well). During the last ratings period in November, Channel 21 received a 2 rating and a 5 share of the audi ence, sign-on to sign-off, according to Nielsen, and a 2 rating, 6 share- from Arbitron. Ratings represent the percentage of all televisions in Transitoriness of Earthly Things” the market being tuned to that channel while shares are the per centage of sets in use at any given time. Channel 39 probably will make its mark quicker than 21, but be cause it’s the new kid on the block it may be a while before it is com petitive among independents. Call 451-6672 for details. Channel 5 is the second highest rated independent station in the country. Channel 39 will bring the num ber of local broadcast stations to seven. In addition to the three in dependents, Las Vegas has three network affiliates and a local PBS station. Station