All-Digital Testing Expands
to other ideas it has proposed
help AM radio, the FCC considers all-digital AM HD Radio technology
to be a “more complex reform” proposal that would require
“additional comment, research and analysis.” The agency called
for further comment on all-digital and other longer-term AM
improvement ideas, such as modification of the pre-sunrise/post
sunset AM operating rules.
session devoted to AM at this fall’s Radio Show brought up the
all-digital option. Panelists were careful to note that NAB is
championing a “digital sunrise” rather than an “analog sunset”
and that the association is not talking about a mandated digital
NAB source told RW that technology transitions take time because not
all stations can “go at once.” Such transitions are best as an
“evolution” and not as a mandate, said this source.
of iBiquity Digital’s all-digital AM technology continues,
meanwhile. Beasley Broadcast Group Vice President of
Engineering/Chief Technology Officer Mike Cooney is now head of NAB’s
Technical Committee; the former head of the group, Barry Thomas, is
now director of engineering at Wilks Broadcast Group, which is not an
Labs had conducted testing earlier on CBS Radio station WBCN(AM) at
1660 kHz in Charlotte, N.C., as reported here and discussed at the
spring show. More recently the organization conducted all-digital
testing on Greater Media’s WBT(AM) at 1110 kHz, also in Charlotte,
and Beasley’s WNCT(AM) on 1070 kHz in Greenville.
data are being evaluated. An engineer close to the committee said,
“We’re not seeing a clear set of results,” due to variations
such as different power levels and air chains of stations tested so
the fall show, NAB Senior Engineer David Layer shared audio clips
received in Boston, Syracuse and Washington of the all-digital
testing. Of the two-day testing on WBT, he said, “As often is the
case with skywave propagation, the first night we got a pretty good
signal in Syracuse. The second night it wasn’t nearly as good.”
said the WBT test was the first time an all-digital AM signal had
been put on a Class A station, “so it was the first time we had
confirmed that you could receive the all-digital signal over the
with the testing hesitated to make any conclusions because NAB Labs
intends to continue the trials.
said he anticipates that, at some point, once NAB Labs has processed
all the data, it would come back to the broadcast community with a
report. Later, NAB confirmed it hopes to present a paper about the
testing at the spring NAB Show.
It’s been some 10
years since there was any testing of the all-digital AM IBOC system.
Should the agency ever approve implementation of all-digital AM IBOC,
it would first need data about the technology’s performance.
indoor tests, the test group used an Insignia Narrator receiver.
Labs is looking for other stations that already transmit the hybrid
analog-digital signal to test, especially Class C AM facilities on
frequencies 1230, 1240, 1340, 1400, 1450 and 1490 kHz, frequencies
not yet used for testing. We’ve previously reported NAB Labs wants
to test on the majority of the band, not just on parts of it.