NAB Labs has been conducting field tests, lab tests and allocation studies related to all-digital AM HD Radio transmission and reception.
The goal is to understand the effect that all-digital AM transmission may have on the FCC’s current rules, according to NAB Senior Director of Advanced Engineering David Layer, should the industry decide to ask the commission to authorize all-digital AM HD Radio transmission.
Field driving tests for nine stations are now complete.
The big takeaways are that the coverage of the all-digital AM signal “greatly exceeds” the hybrid AM HD Radio signal, said Layer. The all-digital AM HD Radio signal is also more robust than its hybrid counterpart.
NAB Labs also learned during the field tests that coverage is “highly dependent on co- and adjacent-channel interference” and nighttime performance “is an issue,” and needs to be investigated more thoroughly, according to Layer. “It’s unlikely a broadcaster would want to turn their analog off at night and replace it with this,” he said.
We’ve reported if the FCC authorized all-digital AM transmission, it would probably be for daytime use first.
Co-channel testing should be wrapped up in a couple of months and he hopes to present that material at the NAB Radio Show.