Practical Operations Concerns about HD Radio & FMeXtra : Aaron Read (WEOS, Geneva)

No, your presenters are not “drinking the iBiquity Kool-Aid”

Practical Operations Concerns about HD Radio & FMeXtra :Aaron Read (WEOS, Geneva)

An “engineering-lite” look at the issues and concerns surrounding

digital broadcast solutions like HD RadioTM and FMeXtraTM

See also : http://www.hdradio.com and http://www.dreinc.com

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

Digital method of broadcasting created by iBiquity Digital Corp & “blessed” by NRSC. IBOC: uses existing AM & FM spectrum.

“Hybrid” system of analog & digital. Backwards-compatible with today’s radios. All-Digital possible in future (not FCC auth. yet)

Allows for better-quality audio, data services, multicasting (FM only).


HD Radio: Hybrid Mode

Analog radios just ignore digital sidebands (white noise)

HD Radios tune to analog, detect digital, buffer for a few seconds, and blend from analog to digital audio. Requires PRECISE delay of analog to match digital’s

~7sec delay If digital signal is lost, blends back to analog.

For multicast channels, radio will mute (most radios will eventually switch back to main channel analog)


HD Radio: Kibbles and bits

AM HD = 36kbps hybrid / 40-60 digital FM HD = 96-120kbps hybrid / 300 digital Based on the HDC (AAC) codec – audio

quality is comparable. It’s all just bits, so partitioning is possible.

Using the bits for things other than audio also possible.


Must my station install HD Radio? Unlike DTV (Feb.2009) there is no FCC

mandate for HD Radio. Market-driven system = listeners may effectively

demand it. Competition with iPods, satradio, podcasts

HD Radio is the only “official” digital broadcast solution to receive the NRSC’s blessing. BUT…technically there could be other IBOC solutions

that are not HD Radio, but none exist as of now.


HD Radio’s benefits: FM & AM Audio fidelity (not quality)

AM sounds like FM, FM sounds like CD (20kHz audio B/W) Elimination of multipath interference

Audio sound is consistent across your broadcast range. FM has multicasting – extra radio stations in one signal. PSD (aka PAD) – Artist / Title & more Data Services: Conditional Access, On-Demand Audio,

iTunes Tagging (one-button purchasing), Downloads, Images/Video…what else?


HD Radio’s problems: FM & AM HDC algorithm is lossy = Source material quality

considerations / cascading algorithms. AM digital sidebands = noisy band (nighttime, esp)

Also true for FM, but not as problematic TIGHT tolerances = Requires GOOD Engineering Initial costs are not cheap: $75,000 - $250,000

Ongoing licensing fees to iBiquity (a different paradigm) Getting in over your head: what exactly you going to do

with those extra channels/features? “Is the ROI really there for you?” vs.

“Is your station’s mission/operation suddenly obsolete?” (eek!)


HD Radio’s problems: AM

Overall: Not recommended! Severe adjacent-channel interference problems,

audio fidelity is questionable, no multicast (data rate too low), Dir.Array questions

Extremely low adoption by comm. broadcasters. Will HD Radio remain the NRSC standard for

digital broadcasting on AM????


HD Radio’s problems: Lic. Fees iBiquity charges steep one-time licensing

fees to buy & activate an HD xmitter. Multicast channels have add’l fees:

$1000/yr minimum or % of revenue. Data services also have fees. Paradigm Shift in broadcaster thinking!


HD Radio’s problems: -10 vs. -20 IBOC digital sidebands are -20dB (1/100th)

to the analog signal.(analog=1000 watts, digital=10 watts)

Controversy that this is not enough ERP. Proposal & Studies for -10dB (1/10th) ERP.

Less efficient = much bigger transmitters ($)More interference concerns.NPR Labs study is a must-read.


What about my FM antenna? Depends on implementation.

Hi-level combining uses existing antenna Ensures equal coverage patterns

Separate antennas has benefits (redundancy, overall simplification) but may have unequal coverage (very bad!) and requires add’l tower space & weight.


Changing Perceptions

IBOC “breaks the norms” of radio. Coverage only to ~60dBu = NO FRINGE!

The FCC’s warned us for years not to count on fringe!! Digital = ON or OFF…no gradual fade to static

Old worries: multipath interference, stereo hiss, not sounding “loud enough”.

New worries: cascading algorithms, bad processing, poor antenna placement / receiver quality, PAD/PSD done right/wrong.


Upgrading your technical plant You may need all-new ($$$) gear!

STL’s: HD data “bursts”, AES output Monitoring: 7 sec delay, multicast channels, remotes,

headphone processing Audio Storage: MP3’s = Cascading algorithms Processing: diff. for analog vs. HD Extra Arbitron PPM’s (if you’re in a PPM market) Extra webcasts of multicast channels? HD not as battle-tested, requires more regular and $$

$ maintenance.


Upgrading your schema

Adding multicast channels is like adding new stations:Extra studios? Processors? Monitoring?

Access control? Audio gear? Computers?Extra staff??? Extra programming???

It’s like having to fill 72 hours every single day.

Are you ready to handle this extra workload?


HD Radio benefits

Bragging rights! Getting late in the game for this, but you might still be able to claim first in your market.

Fitting in with ethos at your college (some are really into “digital media”)

Better teaching environment. Digital Platform = Flexibility for new ideas

iTunes tagging!


Thinking outside the box

Rent out your HD2/HD3 channel for profit. Rent someone else’s HD2/HD3 channel for a

better signal range. Offer to pay to install HD Radio = cheap rent.

Unusual formats on HD2/HD3 5 minute loop of headlines, weather, traffic & sports

plus one or two sponsors. Bring an underserved format to your market! NPR is

a pioneer here: XpoNential Radio (AAA) Radio Ahora (Spanish), Classical24, etc.


Future Thinking: HD Radio

FCC doesn’t mandate it, but your listeners might! Costs are high = Long term planning needed!

Probably longer than you will be at your college. IBOC and/or Multicasting may effectively require

substantial upgrades in automation / studios / STL / processor / xmitter plant IBOC for AM – suddenly that squeaky chair is quite audible! Very different processing vs. sound the same for analog-blend.

Despite greater B/W (~15kHz vs. 20kHz) & no pre-emphasis.

Professional Engineering Support is a MUST!


Shameless Self-PromotionThe IBOC Handbook : Understanding HD RadioTM Technology

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

Newly-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 is right for you!

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

Practical Operations Concerns about HD Radio & FMeXtra : Aaron Read (WEOS, Geneva)

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