How many public TV stations are likely to go off the air as the result of Reagan administration cutbacks in federal support?
Not many, according to observers in a position to judge. The few public TV operations forced off the air will be those already on shaky financial ground and without strong listener support, they say.
Federal cuts may be the catalyst, but poor management, unresponsive ''markets ,'' and overly heavy dependence on government funding will be the basic reasons these ''weak sisters'' fail.
One surprisingly vulnerable station: KCET in Los Angeles, one of the top four public stations in producing ''national'' shows. The station has been carrying heavy debt for some years; it is among stations that get up to 55 percent of funds from government.