First, defeat the elite four then complete the sinnoh pokedex by seeing all 201 pokemon. After completing the sinnoh pokedex, go to professor rowan's lab in sandgem town. Talk to him and professor oak will visit. He will upgrade your pokedex into the national mode. After this, rowan will give you the pokeradar as his gift of thanks. Then, go to route 219[ the sea below sandgem] until you reach 221. There, you will see the palpark. So now, you've unlocked the palpark. NOTE; palpark can only migrate pokemon from an original pokemon gba version and alike language. It cannot migrate a japanese pokemon to an english pokemon version[ diamond, pearl, platinum] even though it's original.
