Wkly Preview: Sensex may drift to 11,800WEEKLY TECHNICAL ANALYSISRex Cano / Mumbai March 11, 2007The Sensex continued to exhibit high volatility for yet another week. The index began the week on a negative note, mirroring the meltdown in market indices across the globe, and the Sensex tumbled to a low of 12,344 (S3 mentioned last week was 12,315) on Monday.The index, however, in the process gave two major negative signals. One, the break of its previous low of 12,800, and, two, the break of 12,635, a crucial support.Following which, the index is now likely to drift to lower levels of 11,800 in the coming days. In case, if the index fails to hold 11,800, then the index may drop to 10,500.On the upside, the index will now have to cross the 13,800-mark to arrest the current downtrend. On the other hand, a sustained stay below the 12,635-mark could trigger accelerated downmove.Coming back to last week