We Need Better PPM Field Tools
Rick Sewell is Chicago engineering manager for
been a lot of discussion over the past year about the resiliency of PPM
encoding. If you had a meter with trending topics on radio broadcasting
websites, it would certainly be near the top. From the PPM encoder, through the
station’s processing and transmitter equipment, out to the listener’s receiver
where it finally reaches the PPM meter, there is obvious trepidation by
engineers, programming, sales, management and owners about the ability of the
system to accurately represent a station’s audience.
have a situation in our local facility that has certainly allowed a little
doubt to creep in for me. We PPM encode our Internet streams. Since we don’t
have a computer constantly monitoring the streams, the decision was made to put
the PPM monitor directly in line after the PPM encoder then into the streaming
encoder. So there is nothing between the PPM encoder and the PPM monitor. You
would think that this would be an ideal situation for the Monitor, and you
would never have a red light as long as you had audio running.
However, this is not the case. We regularly get the red light
on the monitor of all four of our streams. One solution was to put audio
processors inline feeding the PPM encoders. This certainly helped, but we still
see times where we get the red lights. If the PPM encoding has trouble making
it through in what would seem to be an ideal situation, how is it working in
the not-so-ideal real world?
When there is so much at
stake, such as the very competitive PPM-rated market our local cluster is part
of, every station is looking for every advantage it can get. Just one PPM meter
registering a station’s encoding can not only make a big difference in ratings
but the station’s bottom line as well. When you have meters ending up in very
noisy environments, no wonder there was an eager market for a device that
promises to enhance the PPM encoding for a station.
is where the Voltair came in. It’s been about a year since stations have begun
to implement the Voltair in their air chains. The promise of better ratings by
simply inserting a device into your air chain is something that is hard to
resist for most programming personnel in a competitive situation. Our
programming staffs work very hard and sweat a lot of details, from how long the
jocks talk, to “Will this song keep more listeners tuned in than tune out?”
As engineers, we look at the scientific part of this. Does this
masked audio actually make it to the PPM meter? Arbitron (now Nielsen Audio)
provided us with a tool for checking with the PPM encoding monitor. Most of us
by now are familiar with the glow of the little green light giving us
confidence that we have PPM Encoding present on air. We do our best to avoid
the blinking red light letting us know there is a problem somewhere along the
line. After all, it’s been said many times in this competitive PPM environment,
that “If you don’t have PPM encoding you might as well be off the air.” While
no one would actually turn off a transmitter because they have a PPM issue,
that phrase does sum up that the PPM encoding is just as important as our
transmitters, STLs and other vital equipment.
I for one
have always thought the PPM encoding monitors are a useful tool in a general
way; however they don’t really give you the whole story. Most of us have our
PPM monitors set up in the most ideal receiving and listening environments.
They usually get their audio directly attached to expensive receivers which in
turn are attached to expensive antennas. No wonder we have green lights. Good
signals and no background noise to compete with the masked audio.
So, with the green light on the PPM monitor, the job for us
engineering the station is done in regards to PPM. After all, you’re only as
good as the tools you have on hand. I would like to see Nielsen provide
engineering and programming better and more accurate tools for determining what
is actually happening with our PPM encoding in the real world.
What I propose is not more hardware. The hardware is already in
the hands of engineers and programmers. We use it every day. The smart phone
with an app designed to decode PPM would greatly enhance our ability to
determine whether we are getting our encoding out in the real world.
It would not have to be something elaborate or require a phone
with an FM chip. It would actually be more accurate if it simply uses the phone’s
microphone to pick up the audio along with the ambient noise present at that
We could simply open the app, let it listen and
then give us a green or red indication that it is able to decode PPM audio. It
could be that simple. A call sign indication would be useful as well. It would
go a long way in demonstrating that the present system is working or if it
really needs to be improved.
Nielsen has announced that
they are already taking steps to improve the “density” of the PPM encoding. It
would be great if we have an app, like the one I proposed, that would allow us
to do before and after comparisons in the actual field. It might give many of
us some confidence that we don’t need to purchase some encoding enhancement
device; that our encoding is doing just fine.
Read an update on this story by Rick Sewell. This commentary originally appeared in Crawford's "Local Oscillator" newsletter.
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