I added another receiver and the installer added a diplexer and another multiswitch to the line instead of just using a multiswitch that allows four receivers. I can not get locals now. Can anyone suggest a site or a model of multiswitch that of course allows the power to be provided by the receiver to power the antenna and allows four receivers.

if you have 4 receivers the installer should have put them all on one multiswitch. i have 3 receivers and one multiswitch but there is an opening for one more receiver on it.