Wisconsin Public Radio is proud to be among the first radio stations in the United States to implement the new "HD" digital radio service. HD Radio promises to increase the quality and reliability of our signals while adding additional features.

A VERY SHORT HISTORY HDRadio is a term coined by iBiquity Digital Corporation. iBiquity was created in the year 2000 by the merger of the two leading developers of AM and FM digital broadcasting, Lucent Digital Radio and USA Digital Radio. Early in its development, the format was called IBOC or "In Band On Channel" which described the ability to add digital audio channels, not only in the same band (AM or FM), but also within the same channel space already occupied by the existing station. iBiquity now holds the patent on In-Band-On Channel broadcasting in the United States. The Federal Communications Commission (FCC) and some innovative broadcasters were very interested in introducing "digital-quality" radio to existing AM and FM listeners but did not want to allocate more spectrum or move the existing stations to new frequencies. They also wanted the system to be initially "backwards compatible" since there are an estimated 700 million broadcast receivers in the United States! Another reason broadcasters were interested in a digital radio service was the growing popularity of satellite radio (XM and Sirius) and internet streaming or "webcasting". They saw both technologies as long-term threats to the existence of over-the-air commercial and public broadcasting. THE ADVANTAGES OF HDRADIO HDRadio or "In Band On Channel" allows the addition of digitally-produced channels to be added to existing AM and FM stations within their own existing channel space. It gained popularity in the US because: It uses no new spectrum so current licenses remain the same. Every station keeps their current power and class status. It’s compatible with existing stations, services and (initially) receivers. It has lower implementation costs because much of the existing analog equipment can (usually) be re-used. It can be introduced in stages - first a hybrid service (compatible with existing analog receivers) then later a "pure digital" service offering more features and channels (using new digital receivers). In the FM/HD version, the main digital channel can "blend to analog" if the digital reception is interrupted. The FM/HD main channel signal sounds almost CD-quality, drastically reduces "popping" (aka multipath) and increasing the station's "dynamic range". The AM/HD version is stereo and sounds similar to today's FM stations with greatly increased frequency response. Both the AM and FM band systems have other data carrying capabilities and options such as Program Associated Data (PAD) which can display the station's call letters, program or song titles, artist or guest names, news, weather, and even sports scores on the listener's radio. Because of their additional bandwidth, FM/HD stations can carry Secondary Audio Channels (SAC) using a system called "multicasting". One FM station could have as many as two or three audio channels in addition to their "main channel".

"Wisconsin Public Radio is proud to be a pioneer in this new field of broadcasting. We're really looking forward to the new signals and services possible with this new technology." - - Steve Johnston, WPR Director of Engineering & Operations WPR & HD Radio Home How HD Radio Works New HD2 Services Listen to WPR's HD2 All Classical Service Now HD2 Classical Schedule Purchase HD Radio Desktop Receivers Purchase HD Radio Auto Receivers Improving HD Reception Frequently Asked Questions About HD WPR's Tradition of Broadcast Innovation Other HDRadio Links NATIONAL HDRADIO STATUS CHECK Stations on the Air: 1,934 Stations Multicasting: 863 Source: iBiquity Corp