Practical Operations Concerns about HD RadioAaron Read (WEOS, Geneva) An “engineering-lite” look at the issues and concerns surrounding digital broadcast solutions like HD RadioTM No, your presenters are not “drinking the iBiquity Kool-Aid”
What is HD Radio?Hint: the “HD” doesn’t stand for anything! Digital broadcasting by iBiquity Corp. IBOC = In Band / On Channel Backwards compatible All-digital someday, maybe. Bennies: Better audio quality, data services, PAD/PSD, multicasting
HD Radio: Hybrid Mode • Analog radios ignore digital (white noise) • HD Radios = analog > buffer > blend • Seven second delay • Lost digital = blend back • Multicast = mute
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 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? • No FCC mandate (unlike DTV) • Market-driven adoption • Will your listeners support it? • Promotion, sales, installation • Only HD Radio is NRSC-approved • Theoretically, others could do it
HD Radio’s benefits: FM & AM • Audio fidelity (not quality) • AM = FM, FM = CD (sort of)(20kHz) • No multipath • PSD / PAD • Data: iTunes Tagging, conditional access, downloads, etc • Multicasting! (FM only)
HD Radio’s problems: FM & AM Algorithm is lossy AM makes mess of band Requires good engineering Not cheap ($75k - $200k?) Getting in over your head
HD Radio’s problems: AM only Overall, not really recommended Adjacent-channel interference Self-interference Difficulty with Dir. Arrays Nighttime problems w/skywave Very low adoption by broadcasters
HD Radio’s problems: License Fees • Different way of thinking! • iBiquity has steep one-time fees • Multicasting have add’l fees • $1k/yr or % of revenue • Data service also have add’l fees
HD Radio -20dBc vs -10dBc • Standard HD was -20dBc (1/100th) • Deemed not enough by NAB or NPR • FCC authorized blanket -14dBc • Up to -10dBc in some situations • Can require much bigger xmitters
What about our FM antenna? • Short answer: it depends • Hi-level combining • Inefficient, but equal patterns • Separate/Interleaved • Redundant, efficient, but pattern problems & weight/wind load
Changing Perceptions • Breaks the “norms” • Digital = ON or OFF, not gradual fade in/out like analog • NO FRINGE COVERAGE • Old worries = multipath, stereo hiss, not loud enough • New worries = cascading algorithms, pre-processing, listener perceptions
Upgrading your technical plant • May need a lot of new $$$$ gear! • STL – bursty data, extra channels • Monitoring – delays and multicast • Audio Storage – cascading algos • Processing & Preprocessing • Arbitron PPM explosion • Extra webcasts, websites….staff? • HD is a computer – lifecycle?
Upgrading your schema • Adding multicast is like adding whole new stations! • Extra studios, processors, monitoring, access, audio gear, computers, program sources, staff? • 24 hours/day to 72 hours/day • Can you handle the workload???
HD Radio benefits Multicasting – streamline format, appeal to new listeners Fill untapped niches – earn more revenue Potential leasing = more revenue
Thinking outside the box • Rent out your HD2/HD3 for profit • Got a translator? HD2 on it! • Only Part 15? Rent another HD2 • Pay for install, get free rent • Unusual formats • The ten minute loop • Jazz, classical, foreign-language…?
Future thinking on HD Radio • No FCC mandate, but listeners might! • Costs are high = long term planning needed! • Probably longer than you’ll be there • New studio facility may be a must = long-term investment/planning
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 is right for you! Aaron Read can be reached via www.friedbagels.com/blog Need an engineer? www.sbe.org