Instructions
Travel to the north side of Goldenrod City. A large radio tower will be located there. This tower is owned by Team Rocket, your adversaries for much of the game.
Enter the tower and defeat every enemy inside of it. Each time you defeat an enemy, he will run out of the station, never to be seen again. The station contains dozens of Team Rocket henchman and cronies who use a wide-range of Pokemon. Luckily, their Pokemon aren't highly leveled, so you should be able to combat them with whatever types your strongest are.
Return to Route 44 and speak to the man blocking the path. If you have defeated all the enemies in the Team Rocket Radio Station, he will allow you to pass and enter the frozen tundra of Route 44.