Thursday, August 11, 2005
HD (Digital) Radio is a HOAX!
My observations about the proposed NRSC-5 HD radio iBiquity AM and FM digital broadcasting specifications are totally based on actual measured engineering data and scientific facts. Every scientific engineering report and actual measurements of the AM and FM systems clearly have stated that both the proposed AM and FM systems create additional interference on main and adjacent channels. That issue is clear and settled, just read the documents.
NRSC-5 is not completely compatible with analog AM and FM and degrades coverage and audio quality of both the transmitting station as well as other adjacent channel stations. Indeed audio on AM has to be "brick wall" filtered to about 5 or 6 khz maximum bandwidth, and the when an FM station transmits an NRSC-5 iBiquity digital signal, the FM stereo suffers a 6 to 15 db signal to noise (hiss) penalty when received on typical analog stereo receivers. These facts are represented in the original documents filed by iBiquity with the FCC as well as comments filed by independent engineering studies. Read the reports and these facts will become self evident. There is more then enough scientific engineering evidence so that these facts should be accepted by everyone concerned.
The NRSC-5 HD radio iBiqity system, as proposed and now being tested, has a basic compatibility conflict with analog AM and FM and interferes with existing coverage of AM and FM stations. On these points we should all agree. The science is clear.
The discussion about if the IBiquity NRSC-5 proposal is if we should accept the proposed NRSC-5 flaws because of its alleged benefits. That is an emotional, political, marketing, monetary, and subjective judgement, based on future predictions, and is not measurable by scientific instruments. Proponents of the NRSC-5 system are claiming their conjectures are scientific "facts", and anyone who disagrees with them is somehow ignorant, unscientific, or backward. Their comments are rife with bigotry.
The real questions about NRSC-5, that should be under discussion, and my answers are:
1- Is it necessary or desirable to allow a compromise adjacent channel digital system like NRSC-5 to create interference and degradation to existing stations? -NO.
2- Are the huge equipment expense for transmitters and antennas and licensing costs to both stations and listeners necessary to attain the alleged benefits? -NO.
3- Will the analog signal degradation drive listeners away to other services like satellite radio, MP3, iPods, podcasting, and other developing technologies? -YES.
4- Is it necessary or allowable to trespass on your neighbors property (frequency and coverage) to attain alleged future benefits for your station? -NO.
5- Will the public abandon their existing radios and swarm to buy expensive, proprietary new NRSC-5 HD radio ones? -NO.
6- Are there other, currently available, much less expensive, compatible, on channel (not adjacent channel) technologies available that will create the same benefits on AM and FM with fewer of the deficiencies, drawbacks and much less expense? -YES.
7- Is the NRSC-5 proposal consistent with real world FCC frequency and station assignments? -NO.
These are some of the vital questions that must be discussed and resolved before NRSC-5 can be accepted. Yet it seems that most are more interested in emotional, political, opinionated, mudslinging they mislabel as "engineering", "science", and "facts".
I am very much in favor of digital audio and digital broadcasting but I am totally against the NRSC-5 proposal, because it is seriously flawed, misrepresented, problematic, and dishonest.
Fortunately there are other, existing, on channel (not adjacent channel) systems that have far fewer compromises, are much less expensive to implement, and actually provide most of the benefits claimed for NRSC-5!
I will detail these later in my next installment.
The bright future we all envision for digital broadcasting is not to be found with NRSC-5!