Mitchell Lazarus reports for the Communications Law Blog that the Federal Communications Commission is constantly changing allocations to different parts of the radio spectrum to find more space for broadband mobile signals. Analog television signals, for instance, are no longer using the old UHF and VHF frequencies. Now it is clear that the 3.7 to 4.2 GHz band will be cleared for mobile broadband use. Transcontinental microwave systems in the 1950s and 60s carried long-distance telephone calls and network TV programs on the frequencies, which is still used for microwave links as many as tens of miles apart. Many satellites used 3.7-4.2 GHz for television program distribution to giant backyard dishes. The microwave traffic left these frequencies for fiber optic cable. But satellite systems still use 3.7-4.2 GHz signals today, particularly for video distribution. The FCC already, last August, issued a Notice of Inquiry about what the frequencies future should sound like. "The omnibus spending bill that Congress passed in March included the MOBILE NOW Act, which directs the FCC to report on 'the feasibility of allowing commercial wireless services, licensed or unlicensed,' to use or share 3.7-4.2 GHz," Lazarus writes. Now the FCC is taking comments through May 31 on what services should be dedicated to the part of the radio spectrum, though all suspect some kind of mobile service to be using 3.7-4.2 GHz in the future.