In
a recent petition to the FCC in the United States, a Texan broadcasting
corporation rightly points out that “all-digital systems represent the
future of radio.” This is the premise of its request to allow the
introduction of pure HD in the medium wave in the U.S. As some
broadcasters are questioning the current performance and the limited
testing of HD in this band and its reception quality and coverage, such a
request has certainly opened a digital Pandora’s box. It has also shown
that something better than the current simulcasting scenario (mainly
used in the FM band, with its own interference issues) is needed.
“Simulcasting”
is a bit like “digital” or “hybrid” and can have a lot of meanings and
nuances. The word generally refers to broadcasting in analog and digital
at the same time, whether in the VHF or AM bands (mainly medium wave,
as simulcasting in shortwave could be a step too far and engineers do
not really recommend it).
Simulcasting exists in pure
digital. In a very broad sense, we could say that DAB can broadcast
simultaneously up to 18 (different) programs covering the same area and
using a chunk of 1.5 MHz of spectrum in Band III. Or DRM can broadcast
up to three (different) audio programs and one data program using the
spectrum occupied by an analog medium wave channel or half a FM channel
(96 KHz) and in Bands I and III as well. Some broadcasters have taken
the simulcasting route (same program in analog and digital) in the
belief that it will deliver the same power and coverage in both modes —
nonsense in physics. This would be a bit like sharing an apple between
two brothers and hoping that each will enjoy the whole fruit.
Even
if digital radio is less energy hungry than FM or AM (DRM for example
only requires a maximum of 10% of the power needed for FM analog),
simulcasting needs compromises simply because analog and digital carry
audio differently. Simulcasting requires extra equipment, extra energy,
if the same coverage is to be maintained, extra planning and extra care.
So
why go for simulcasting then, at all? Simulcasting is a good way to
introduce digital radio and the extra benefits related to audio quality,
richness of content and data. India has taken this path with its 35
medium-wave transmitters that simulcast in analog and DRM, while slowly
introducing pure digital DRM.
As digital transmitters
are calibrated and receivers slowly emerge, ready to be bought by the
listeners, simulcasting is a valid transition path.
In
DRM, at least, one single transmitter can support broadcasting both an
analog and a digital DRM signal side-by-side, or even where available in
the band (this refers mainly to the VHF Band II). The extra costs of
simulcasting dictate, though, that a switch off date needs to be set, as
this concentrates the minds and efforts and does not stretch the
project into uncertain times. And like so often, timing is everything.
There
can be an abrupt switch off, like in Norway. There can be a transition,
a voluntary switch to digital (medium wave) only, as it is on the
discussion FCC agenda just now.Or there can be a consultation, a digital
review, as recently announced in the United Kingdom. The British
Digital Minister rightly considers that, due to the changes in
technology and competitive landscape in the past five years, “the debate
about the future digital transition program for radio has shifted.”
So,
while switch off straight away or simulcasting seemed the best two
possible scenarios, the situation looks a bit more complex with the
addition of IP or broadband delivery and other platforms to the digital
radio mix. After all, when a program is terrestrially broadcast and also
streamed, we also have simulcasting.
This digital
cocktail preoccupies many of the broadcasters, the politicians and
especially the observers of the mysterious millennials or “snowflakes.”
The figures are quite clearly in favor of terrestrial. In the U.K.,
online and apps deliver 11%, the channels on digital TV 5%, with DAB
digital radio scoring about 40.4%, the result of the push and investment
of almost three decades. In Australia FM is still supreme with 7.8
hours listening a week, AM 4.7 hours, digital radio 1.3 hours and online
1 hour (according to the research commissioned by the regulator in May
2018).
Is simulcasting then the dawn of digital radio?
Or is it a permanent state of affairs paralyzing those afraid to lose a
significant, though maybe declining analog audience, but very keen to
chase new younger audiences and their new digital habits?
Simulcasting
the same programs on both analog and digital only makes sense if analog
cannot reach them (as it happens in parts of India and surely
elsewhere). Maintaining the analog signal and adding the digital part
immediately offers the chance to present the same channel but, at least
in DRM, also bring new content on at least the two extra channels
created in digital. These can be used for new content and can increase
revenue opportunities while increasing competition. In this way
simulcasting offers enhanced capacity to carry the same in analog and
digital but also something new and better, more attractive that can
prove the advantages of digital radio.
Simulcasting
can stifle or enhance radio. In the U.S., leaving simulcasting and
pitching for pure HD in AM is seen as a way of saving the valuable
medium-wave band. There are other ways, too, as mentioned by Larry Todd,
vice president of WRNJ Radio, in the article he wrote for Radio World
on a solution to the AM Problem.
Simulcasting analog
and digital radio signals is more than a technical issue. It is about
creating new attractive content rather than just duplicating existing
programs and formats. It is about accepting competition, opening the
radio market and about a strong belief in radio and its digital
terrestrial future.
If simulcasting is just buying time for an unidentified “better” hybrid future, digital radio will remain in limbo.
Source:-https://www.radioworld.com/
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