Commentary: Digital Is a Hungry Bandwidth Beast
I read with great interest the commentary by Joe D’Angelo of
iBiquity Digital Radio (“AM
Radio: Where Do We Go From Here?” Sept. 26 issue) regarding
HD Radio as a path for AM to evolve. I also read the reader posts to
that piece. All interesting.
have had the privilege to speak with a few people from iBiquity in
the past and, even though our points of view differed, the
conversations were always cordial. I was offered the same experience
from the folks from DRM. These conversations are what make
broadcasting fun and exciting, especially from a technical point of
of the reader comments to this article resembled arguments made about
Microsoft’s dominance of the computer marketplace. Okay, let’s
use that analogy to discuss the two major forms of digital
equate iBiquity vs. DRM to the Microsoft vs. Linux debate. One you
pay for the privilege to use, and the other you get for next to
nothing. Yet another analogy is closed source development vs. open
let’s talk about some real-world issues. Digital broadcasting is a
hungry bandwidth beast. There can be no argument here. I have
personally listened to the effects in several markets and it isn’t
pretty. Digital is not a good neighbor. Get enough digital neighbors,
and you wind up in a “radio slum.”
down to the issue of the medium-wave broadcast band and digital. (We
can no longer call it the AM band.) The big questions are: At what
power would one be able to run, and will it even work properly with
multiple tower arrays that most of us have to run?
have seen the bandwidth proof of the system I take care of and, quite
frankly, it stinks. Even AM stereo would sound lousy on this array.
These are facts, not pipe dreams or pessimistic ballyhoos.
Let’s go a step farther with real-world performance expectations.
In my case, I have a 5 kW AM (aka medium-wave) and a 100 kW FM that
are at the same ground level. After a survey I determined that the
two stations covered the same area. (Not a usual situation.) So,
other than fidelity and noise, both were equal.
this in mind, and depending on the allowed digital power, this would
equate to either 1 kW or 500 watts for the former 5 kW AM facility.
(That would mean huge power savings, by the way.) But then, we have
the issue of nighttime power vs. the four-tower array. This could be
bad for Gotham City, i.e. 540 watts or 270 watts vs. 2700 watts
Things don’t look good for Batman and Robin.
we have to cover the same area, let’s talk about this for a moment.
In the case of DRM, you need a rather significant signal-to-noise
ratio to get DRM to decode. The approximate same scenario also
applies to IBOC.
the SNR is not met, the listener hears nothing at all. Instant
tune-out occurs, assuming pure digital. Now you have the general
manager and station manager on your back after you have spent a lot
of money and time to implement the new wave of broadcasting.
to sell the listener on HD Radio is the main focus. Let’s be
honest. It will take deep pockets and large promotions to get the
ball rolling. If it is done right, the returns could be significant
indeed, but it is up to the station(s) in question to sell HD Radio.
Don’t depend on the listener to get excited and go out and pop the
money to try your grand experiment.
In this same vein, don’t expect the listener to get excited when
all you are presenting is lame programming. One has to present a real
reason to listen. Give them something to talk about, brag about.
It is a huge investment that will take time to pay off. The upside is
that there is so much young talent out there; this should not even be
an issue. Get these young people excited.
the medium-wave band survive? No one knows for sure, although Europe
is sure it is completely dead and worthless. I don’t subscribe to
that thinking at all. There is a lot we can do and should do.
are truly blessed to have Commissioner Pai as our advocate. Give him
a good reason to be just that.
Payne is a contract engineer with Townsquare Media, Western Division
in Twin Falls, Idaho.