What is HD Radio?
HD Radio uses an in band, on channel (IBOC) method to transmit up to three digital program streams combined with the existing analog signal over an FM broadcast transmitter, or a single digital program stream combined with analog on an AM transmitter.
Will I need a special radio to receive the digital signal?
Yes. Currently there are only a few on the market, Boston Acoustics being the leading one at this time, but more will soon follow.
Will my existing radio become obsolete or be degraded by the digital signal?
No, not under normal circumstances. Studies show that a few cheap, poorly made receivers may experience a small increase in hiss in the signal, but the vast majority will do just fine. There is no mandate to turn off analog AM or FM as there is with analog TV, which is scheduled for deactivation in 2009. Some AM news and talk stations have chosen to decrease their analog bandwidth from 8 kHz to 5 kHz to give themselves a bit more digital bandwidth, but not FM.
Will HD Radio be CD quality?
No, but it will offer many advantages. CD quality requires a 1.5 mbs (megabits per second) stream and the FM signal can only accommodate a 96 kbs (kilobits per second) stream. The Ibiquity Corporation, the developer of the digital encoding algorithm, took great care to design a system that is far superior to the average mp3 player used by the home computer. An HD Radio listener will immediately notice the absence of hiss and multipath noise associated with analog FM and the elimination of static and power line noise associated with AM reception. The digital FM transmission will also offer a frequency response of 20 Hz to 20 kHz, an improvement over the 15 kHz top end limit of the current system.
Will I be able to hear additional programming on my digital radio?
Yes, this is probably the most exciting feature of digital FM. WSHU now broadcasts both our existing programming on HD1, and the news and talk programming from our sister station WSHU-AM on HD2, all from our 91.1 transmitter.
Will HD Radio improve my fringe area reception?
No, not currently. The digital signal has not proven to be as robust as the analog. Good digital reception is currently limited to a stationís prime reception areas. This may improve with better receivers and transmission technology as time goes by.
Will existing embedded services such as reading for the blind carried by some stations be affected?
No, studies show that IBOC transmission of HD Radio has no affect on the FM subcarrier transmissions used by these services.
What other features can I expect?
HD Radio offers the potential for quite a few additional benefits. At the start, Program Associated Data (PAD) will include such items as song titles and information about upcoming programs, displayed as text on a small screen on your HD Radio. Future uses may include weather bulletins and other emergency information, news headlines etc.
See pictures of the new WSHU HD Transmitter
* HD Radio is a trademark of the Ibiquity Corporation