Spectrum

The Communist Party of India [ Images ] (Marxist) has demanded an enquiry into what it claims is a Rs 60,000 crore (Rs 600 billion) financial scam involving the manner in which 2G spectrum was allocated by the Union ministry of communications.
In a statement issued on Thursday, the CPI(M) said that the United Progressive Alliance [ Images ] government had given away scarce spectrum at a fraction of the market price leading to heavy revenue losses to the nation.
'It is now clear from the sale of shares by Swan and Unitech that more than Rs 60,000 crore has been lost to the national exchequer by giving away scarce spectrum at a fraction of the market price. The CPI(M) is shocked that the United Progressive Alliance government, instead of addressing the huge scam that has taken place on the allocation of the fourth licence in 2G mobile services has taken the position that nothing needs to be done,' the statement said.

I know "spectrum" means "wide range of something" usually, but I wonder what it means here.

Source : http://www.rediff.com/money/2008/nov/06left.htm