You have to get into the tower and beat team rocket.
Just save the radio tower....you will get it as a reward.
In the radio tower after you answer a quiz
Goldenrod City Radio Tower.
lavender town
goldenrod city.
kill him!
you can't
You have to go to the radio tower to answer the quiz to be able to challenge Whitney's gym.
Lavendar town.
The Kanto radio tower is in Lavender Town.
you can't
So simple