Ammonia observations at radio wavelengths have proved to be a
 useful probe of the physical parameters of dense molecular
 cores. We wish to test the models of the "hot cores" found
 in regions of massive star formation which are thought to be
  the birthplaces of O stars. We want to do this using the
 rotational transitions of ammonia which can be observed by
 the LWS.  We expect to observe absorption lines in many of
 our sources which will allow us to probe a different regime
 than that available to radio observers.