I am reading Unwired to see how one builds a Nexus -- my players want to build one. It mentions that 'Signal is normal cost'. I can't find the cost of raw signal. How much does it cost, and where can one find it?

It's in the table at the end of the Wireless World chapter of SR4, next to the cost of increasing the Response of a commlink.

Found it. Thanks. I'm not so up on Matrix stuff in 4E as my players usually don't play Hackers and so I handwave it.