IBOC / HD Radio TM : Engineering Concerns Aaron Read (G.M. : Finger Lakes Public Radio)

No, your presenter is not “drinking the iBiquity Kool-Aid”

IBOC / HD RadioTM : Engineering ConcernsAaron Read (G.M. : Finger Lakes Public Radio)

Already decided HD RadioTM is right for you? Here’s a look at what you’ll

need to do.

A little housekeeping first…

CBI listserv: www.askcbi.orgOpening for Student position on CBI

executive board. E-mail app to [email protected] by Nov.15th Must still be a student thru Dec.2011

Fill out a feedback form, dammit!!

Essential Questions

Session is not about operational issues / concerns.

It’s about the engineering of HD Radio, and how it applies to your situation.

Are you an AM station?

We’re not going to talk much about AM.

Has a lot of problems, is only sparsely implemented.

Download these slides: www.friedbagels.com/cbi/

What is HD Radio?Hint: “HD” doesn’t stand for anything

HD Radio=brand name Digital sidebands

straddling the analog carrier

Some RF energy on adjacent channels In-Band / On-Channel =

“IBOC” Backwards-compatible


Is it required?

Unlike DTV in 2009, it’s optionalAll-digital possible, but not

authorized by FCC yetPressure to migrate comes from

listeners, marketplace, campus politics, etc.


What happens with HD Radio?Analog > Buffer > Blend to Digital

Takes a few secondsAnalog delay for time-align

IBOC uses HDC (AAC) codec If HD is lost, blends back to analog

Or mutes for HD2, HD3, etc


Simple FM IBOC Transmission Topology – All IBOC Gear at Transmitter Sitediagram courtesy of The IBOC Handbook, page 401

FM IBOC Transmission Topology – with Exporter and Exgine Modulesdiagram courtesy of The IBOC Handbook, page 405

FM IBOC Transmission Topology – with Exporter & Exgine Modules, plus Importerdiagram courtesy of The IBOC Handbook, page 413

What is HD Radio? (FM)

Digital carriers = bits & bytes 96kbps std (+12 or +24 ext.hybrid or “MP3”

mode; More carriers closer to analog carrier = no work with 92kHz SCA)

Multicasting (HD2, HD3…HD7) PAD/PSD, iTunes Tagging, Downloadable

Content, etc. 20kHz audio bandwidth No multipath interference or stereo hiss


What is HD Radio? (AM)

Also just bits & bytes, just 32kbpsNo multicastingPAD/PSD, just barelyImproved audio quality


Multicasting

Killer appExtra stations hidden in the signalRequire an HD tuner to hearSubdivides 96kbps total

Ext.Hybrid is separate


iTunes Tagging

www.hdradio.com/iTunes_TaggingPress TAG buttonRadio saves tag to iPodNext time iPod synchs, iTunes

buys it automatically Very cool, but limited receivers /

stations doing it.


More HD Radio power, pleez! Standard was -20dBc (1/100th) FCC blanket increase to -14dBc

Up to -10dBc in specific cases Hi-lvl combining / common amp – derating by 50%

-20dBc common amp TPO = 4.00kW (16.0kW) -14dBc common amp TPO = 2.65kW (10.6kW) -10dBc common amp TPO = 1.98kW (8.52kW)

Means a MUCH bigger transmitter is needed! MUCH better HD coverage – better for HD-n, too


FM translators and boosters Boosters (Single Freq. Network)

NRSC-5 specs carrier synch, but no radios support it yet. Only prelim testing.

Translators require separate iBiquity license (i.e. $20k)Unless you get a heterodyning xlatorWEOS/W212BA case study


FMeXtra?

Digital SCA (Subcarrier) service Compatible with hybrid IBOC, but not

all-digital IBOC. Transmits 64 – 156kbps

Stereo, RDS, analog SCA = less kbps avail. Transmits DATA, but architecture only

supports audio via AAC at the moment.

Shameless Self-PromotionThe IBOC Handbook : Understanding HD RadioTM Technology

Looking to really learn the engineering of IBOC / HD Radio? Read this book! First Overview of the Approved

NRSC-5 (IBOC) Standard. Authored by David Maxson Illustrated by Aaron Read

Available on Amazon.com

Final Thoughts

Questions – and please no: Rants, Screeds, Diatribes, Harangues, Raving, Tirades, Bullyragging,

Vociferation, Bloviating, Railing, Objurgating, Badgering, Molestation, Nettling, Ruffling, Badgering, Pestering, Heckling or Persecution.

Tell us your situation, we’ll opine if HD Radio or FMeXtra is right for you!

Aaron Read can be reached via www.friedbagels.com/blog Need an engineer? Yes you do! www.sbe.org

IBOC / HD Radio TM : Engineering Concerns Aaron Read (G.M. : Finger Lakes Public Radio)

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