More information needed please.
Is your setup something like:
Dish -----coax cable ------->Old RCA TV
or
Dish ---flat brown cable -----> Old RCA TV.
Any make, model, or other information about the dish?
Does the TV work with other signal inputs?
Do other TV's work with the dish input?
Any other devices, adapter's, or other components between the dish and TV? If so, can you see any make and model information?
Need to narrow things down some.