IBOC / HD Radio Engineering Concerns

Aaron Read (G.M. : Finger Lakes Public Radio)

TM

:

Already decided HD Radio TM is right for you? Here’s a look at what you’ll need to do.

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

A little housekeeping first…

 CBI listserv: www.askcbi.org  Opening for Student position on CBI executive board. E-mail app to [email protected] by Nov.15

th  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

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

Is it required?

 Unlike DTV in 2009, it’s optional  All-digital possible, but not authorized by FCC yet  Pressure to migrate comes from listeners, marketplace, campus politics, etc.

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

What happens with HD Radio?

 Analog > Buffer > Blend to Digital  Takes a few seconds  Analog delay for time-align  IBOC uses HDC (AAC) codec  If HD is lost, blends back to analog  Or mutes for HD2, HD3, etc

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

Simple FM IBOC Transmission Topology – All IBOC Gear at Transmitter Site

diagram courtesy of The IBOC Handbook, page 401

FM IBOC Transmission Topology – with Exporter and Exgine Modules

diagram courtesy of The IBOC Handbook, page 405

FM IBOC Transmission Topology – with Exporter & Exgine Modules, plus Importer

diagram 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

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

What is HD Radio? (AM)

 Also just bits & bytes, just 32kbps  No multicasting  PAD/PSD, just barely  Improved audio quality

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

Multicasting

 Killer app  Extra stations hidden in the signal  Require an HD tuner to hear  Subdivides 96kbps total  Ext.Hybrid is separate

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

iTunes Tagging

 www.hdradio.com/iTunes_Tagging  Press TAG button  Radio saves tag to iPod  Next time iPod synchs, iTunes buys it automatically  Very cool, but limited receivers / stations doing it.

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

More HD Radio power, pleez!

     Standard was -20dBc (1/100 th ) 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

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

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 xlator  WEOS/W212BA case study

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

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-Promotion

The IBOC Handbook : Understanding HD Radio TM 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