How do you get the PokeRadar in Diamond?

Question

I want a PokeRadar for Diamond so I can catch an Aron at Fuego's Iron works. Do you guys know how to get it?

Answer 1

>The Poké Radar is obtained from Professor Rowan in his lab immediately after receiving the National Pokédex from Professor Oak; however, he will not explain how it works very thoroughly. In Pokémon Platinum, once the player talkes to Dawn/Lucas's sister about Pokémon outbreaks, Dawn/Lucas will give a more practical demonstration on Route 202. ~ Bulbapedia

You receive the National Dex after seeing every single Pokémon in the Sinnoh Regional PokéDex (Oak is in Eterna City, near Cycling Lane).

Happy hunting!