You don't. The Pokegear radio plays Hoenn and Sin oh music on some days. It's just like it!
There is no PokeRadar in HG/SS, unless you count the PokeRadar in the PokeWalker.
You get it from someone. Hahaha. You get it in Ecrutic City.
Check your PokeDex. All Pokemon which areas are glowing red need the pokeradar to find them.
A pokeradar is a device used in Pokemon to find legendary Pokemon. In the grass there are the Pokemon from the normal pokedex. but, if you were to use the pokeradar you will find legendaries. For example lets just say you are going through route 209 and you see wild grass while standing in it use the pokeradar and you could find a matang. that was an example. you do not find matang in route 209
To get a pokeradar in Pokemon diamond and pearl, you must see all of the sinnoh Pokemon in the game, then go to profeser rowan's lab and talk to him. he will give you a pokeradar and with it you can find Pokemon from other regions.
Normal Pokemon that appear in that area.
pokemon, some of which you wouldn't otherwise be able to find.
you cant, you have too migrate it from leafgreen or from firered. by Scott
the pokeradar finds Pokemon that you can't find normally when walking through a patch of grass, but most of the time the Pokemon that do appear are the common ones.
the Pokemon that dawns little sister tells you
the Pokemon you would normally find but with pokeradar you can get the shiny version of that Pokemon but that takes hours and there are some special rules for to get it. also pokeapp 20 is something you can use with using the pokeradar
sometimes you can use pokeradar. if you us pokeradar and get 599 smurgles the 600th will be a wyruant