You have to defeat Team Rocket at the Radio Tower in Goldenrod first. And mahogony secret base too.
fail...
Mahogany Town.
There IS no Radio Tower in Mahogany town
Battle Team Rocket in Goldenrod.
in shop at mahogany town
at the lake of rage outside of mahogany town
After you beat them in mahogany town.
TM46 Thief is located in Mahogany Town Hideout.
Blackthorn City, after Mahogany Town and after Ice Path
It is in Mahogany town in the southwestern corner of the town.
TM49 Snatch can be found in the Mahogany Town Rocket Hideout.
the HQ is in Mahogany Town in soul silver im not sher about hart gold