New Delhi, Nov. 19 -- State-owned Bharat Sanchar Nigam Ltd (BSNL) has flagged weak transmission signals at thousands of its new 4G towers-an issue behind call drops and slower data speeds-at a time when the operator is attempting a long-awaited turnaround backed by the government's successive revival packages. The company last month asked vendors Tata Consultancy Services (TCS) and Tejas Networks, a Tata group company, to investigate and fix the problem, according to people familiar with the matter and a letter seen by Mint.

In response to Mint's queries, TCS and Tejas said most of such issues have been fixed and there is no impact on the company's key performance indicators (KPIs).

The issue assumes significance amid concerns over BSNL...