Nautel-Digital-Radio-Showcase-Hal Kneller
Hal Kneller is a 40 year veteran of the broadcast industry working both as an engineer for WGCU, WGSM, WCTO, WPAT as well as owner/operator of five of his own stations.
Before joining Nautel as Market Development Manager, Hal worked for iBiquity Digital Corporation as Director of International Broadcast Development where he played a pivotal role in the promotion of Digital Radio.
With his unique insight into the complex issues surrounding HD Radio, Hal is happy to assist broadcasters contemplating the move to digital to ensure they make the decisions that are right for them.
If you have any questions about Digital Radio you can contact Hal directly at [email protected]
Read more Digital Radio Showcase
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by Hal Kneller


Conditional Access (CA) is a technology by which the ability to hear an audio stream or access a data service over HD RadioTM signals would be inhibited except for those so authorized. While the idea has been around for a few years and there have been some experiments by several broadcasters using multicast audio or data services, the system hasn’t really gained much traction. Earlier implementations were somewhat expensive and, at times, unstable. In order to secure the desired broadcasts, make it easier for broadcasters, and of course, cost effective, there has been some system redesign.

The current thinking is to have NDS (developer of the HD Radio CA system RadioGuardTM) host a database and control the CA from their server farm. Stations would require an Importer SSL software application, and not a separate hardware box (formerly known as the Protector). Stations would contract with NDS, and via a web browser, enroll receivers into the system removing the need for the Initiator hardware box, and transmit required information back to NDS. By subscribing through NDS as a service provider, stations eliminate the worry and expense of purchasing and maintaining equipment to support CA. There is an exception to the enrollment in that a manufacturer may authorize a class of receivers at the factory, such as the new JVC KW-NT3HDT HD Radio receiver with GPS navigation and real-time traffic guidance.


The initial system illustrated here had all the equipment at the station connected to a national database housed at NDS. Current thinking is to move the system to NDS and link to the station's Importer via IP.

According to iBiquity, all of the current chipsets for HD Radio technology support the required serialization and data encryption for CA, which is either an audio program (on any one or more multicast channels except HD-1), or a data service such as real-time traffic. However, it may be a year before consumers actually see these on store shelves given the time it takes manufacturers to implement.

The system requires both a serialized receiver (similar in concept to the Electronic Serial Number or ESN in a cell phone), and data encryption of the audio (or data) stream so that NDS can both recognize the receiver’s serial number as being valid (permissioned), and send information to decode the encryption creating a double security system. This is similar to cable or satellite TV set top boxes which determine the channels a subscriber can access, technology in which NDS already plays a major roll.

Potential applications for CA include audio information services that provide news, magazines and books to blind and print-handicapped people (stroke victims or amputees). Copyright laws state that such services should not be broadcast openly to the general public making CA an appropriate technology for their use. Other uses include a pledge-free channel to public radio listeners who have already paid their membership fee, adult entertainment, concert channels, and other special programming.

CA could be charged per program, for a given time period, or free with access restricted at the station’s discretion. The first commercially available receiver – available through the Internet – the Dice iTR-100A is specifically designed for audio information services and accessible by people with sight disabilities. It is otherwise a fully-functioning HD Radio receiver featuring RBDS on the display, which many tabletop receivers have never offered.

If you have any questions about Digital Radio you can contact Hal directly at [email protected]

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