19 Across, Observational device,research facility invested in 4,possibly (9) A?T???A??
23 Across, Has nothing to do with dreadful noises surrounding broadcast (7) D?????S
28 Across, Line in restaurant, curtailed then dropped,is fruit dessert (9) C???O?T??
4 Down, No opening for straw hats - stetsons required in these (6) ?A?E?S