[Voldemort]

You choosed wrong function

LimitGlobalChatRadius(10); is to limit how far each other player can see others chat,

Better use

pawn Код:

new Float:x,Float:y,Float:z;
GetPlayerPos(/me cmd maker,x,y,z);

for(..
if(IsPlayerInRangeOfPoint(i,Your Radiuss,x,y,z))
{
SendClientMessage(..
}