Dish Size

Hi Sir ,
When we are seeing the EIRP levesl in lyngsat  maps  for the the location . It will show EIRP and  dish size (cm/In) .So how to consider that  values. Suppose EIRP level showing 38 dbw and recommended size 190 cm/74.8 in .
What does it mean .. Do we need to use 1.9 m ( diameter of major axis in circular antenna)  dish  as minimum  requirement  or  other ?
Also  if we want to transmit  on the same dish ..  with different carrier like 512Kbps or 1024 Kbps ..
will that same dish supports  as per the maps .
Please clarify my doubts ..

Thanks in advance
Regards
techtest