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More Thoughts on What ATSC 3.0 Can Teach Radio

Alan Hughes responds to Dan Slentz’s musings

Alan Hughes

The author comments here after reading the commentary “What Can ATSC 3.0 Teach Radio” by Dan Slentz.

Over-the-air TV, like broadcast radio, is the cheapest and fastest way to communicate to large audiences. These are one-way communication systems where the whole audience gets the same thing simultaneously.

It is possible to separate parts of the audience using the Alternate Frequency System available in DRM and DAB+ digital radio, which can specify areas as small as 7 x 7 kilometers (4.35 miles x 4.35 miles). It requires GPS to be automatic from the user’s perspective, but it won’t work indoors since the needed satellite GPS reception is blocked.

Since broadcasting and OTA are one-way systems, how and where are the data to make appropriate individualized advertising to be gathered? Smart TV’s microphones and cameras? Existing smart speakers provide data, which could be sold, which will enable control like cable TV companies have had.

Is the broadcast industry ready for the privacy issues of having microphones and cameras always on while watching TV?

Dan Slentz in “What Can ATSC 3.0 Teach Radio?” suggests using the MAC address. Consider the data requirements to send for an audience of a million TVs and sending the different content data as well as the 48-bit MAC address a million times. How long would that take? The remaining available data rate available in HD Radio once the sound data has been used is tiny for additional content such as unique addressing and its unique information.

After 20 years, ATSC 3.0 is finally an admission that COFDM modulation, which is used in all other digital TV systems outside of North America and South Korea, is much better than ATSC 1.0. COFDM can reject reflected signals (in the analog days these were called ghosts). The extensive use of outdoor TV antennas has kept broadcast TV popular as it is free to the user and the signal reliably is good.

ATSC 1.0 uses MPEG2 compression, the least efficient system; and in much of the rest of the world MPEG4 compression is used, which halves the data rate, allowing for more HD programming. Now ATSC3.0 is capable of Ultra High Definition because of the latest compression, which halves the data rate again. However, UHD requires more data for the extra sharp images.

I agree that having more channels from the same transmitter does not necessarily improve profits. In Australia all TV stations transmit two high-definition programs and three standard-definition programs. The SD programs are generally old reruns, cheap programming or advertorials that the advertisers pay the broadcaster to transmit. These programs generally get much lower ratings.

The problem with FM zoning is that the translators are located in areas where the main signal is poor, not where a particular audience type lives. DRM and DAB+ use the Alternate Frequency System which can specify the four-corner GPS co-ordinates of a rectangle as small as 7 x 7 kilometers and send the data to that area. It is not part of the HD Radio specification.

Advertising the presence of the steakhouse down the road is already being done by Google via cellphones and smart speakers.

The reason the cable companies became dominant in TV was because of the selection of “Never Twice the Same Color” (i.e., NTSC analog TV) and later ATSC 1.0, which with the use of indoor antennas shows the wrong hues, ghosts and, in ATSC, unreliable reception.

ATSC 3.0 can broadcast up to 57,000 kbps. It is difficult to have new innovations with HD Radio because the highest bitrate is only 96 kbps, and nearly all of this is required to get reasonable sound quality or for additional, poor sound-quality, subchannels. For AM HD Radio the number is either 20 or 40 kbps.

In HD Radio, you need to use the primary and secondary signals. In all-digital HD FM, the secondary digital signal is radiated at 1% of the main signal power, which makes the reliable digital coverage area much smaller than analog. By comparison DRM can have up to 186 kbps and all digital signals are of the same power which is not limited by interference to and from adjacent channel broadcasters including your own.

The author is a broadcast technical author from Australia and has spent a lifetime in training technicians. Radio World welcomes opinion and points of view on important radio broadcast industry issues. 

[Also by this author:“A Better Way to Revitalize U.S. Radio”]