I Call For Revisiting The Transmission Standard — David D. Smith, Sinclair Broadcast Group

by David D. Smith, President, Sinclair Broadcast Group
Friday, April 2, 1999

As you may recall, over two years ago we (Sinclair) and several other broadcasters initiated an industry discussion regarding the amount of transmission power that UHF stations would be permitted to have in order to provide equivalent geographic coverage to that of today. While the initial powers granted to UHF broadcasters were significantly below that granted to VHF broadcasters, a coalition within the UHF industry was successful in establishing much higher power levels that enabled a fair replication of today's coverage.

During the initial effort to resolve the UHF power issue, we became suspect of the transmission standard known as 8VSB. Our suspicion was focused on the concern that the 8VSB modulation standard could be fatally flawed because of its sensitivity to a condition commonly called "multi-path". Over the last two years, while waiting for the availability of commercial DTV receivers, we took the opportunity to learn more about the 8VSB standard. Several weeks ago we conducted a simple test in Philadelphia and reached a preliminary conclusion that the 8VSB transmission standard could not replicate our current coverage for indoor reception inside of our City Grade contour. Please take a moment to review the following piece by Nat Ostroff for additional information about that test.

Our investigations and Philadelphia test lead us to believe that we need to take the following action. We must revisit the transmission standard and determine if today there is a better solution than the current one. We do not need to examine the entire standard, only a very small portion of it. Our sense is, there may very well be a more appropriate solution for our industry. Many other countries have adopted a transmission standard called COFDM. Therefore, before any final conclusion can be reached, a side by side comparison test should be run. Without wanting to over-dramatize this issue, let me suggest that transmission power issue was a 1 on a scale of 1 to 10. This issue is a 10 on the same scale. We need to know the facts and we need your support to push ahead. We will be circulating a letter to the FCC and any other necessary government agencies asking them to support this test for the benefit and furtherance of over the air free television.

We would be happy to discuss the results of our Philadelphia tests with you so that you can better understand the magnitude of the problem. Please contact us by phone or e-mail. If you feel that a meeting should be arranged at NAB, call me immediately.

Sincerely,

David D. Smith,
President
Sinclair Broadcast Group

4/2/99

TO: All Broadcasters Concerned About Their DTV Coverage

FROM: Nat Ostroff, Vice President, New Technology
Sinclair Broadcast Group, Inc.

SUBJECT: Consumer Reception of DTV in the Home - A Call for a Test

Can we afford to lose the ability to reach into our consumers' homes that are located inside of our Grade A and City Grade contours, just for the privilege of becoming digital broadcasters? At Sinclair, we answer to that question with an unequivocal NO!

On March 24th, 1999 a meeting was held in Washington, DC with a small group of broadcasters to review the results of a series of tests performed in the Philadelphia market to determine the consumer's ability to receive DTV signals indoors. The selected test sites were restricted to be inside of the City Grade of the four high power, co-located, DTV stations on the air in that market. The criteria for success was the ability to receive DTV pictures when good NTSC pictures were available using antennas suitable for indoor applications.

The results of those tests, based on the above criteria, indicated that the 8VSB modulation system, that is part of the ATSC standard, provides inadequate reception in homes, inside of both the City and Grade A contours. In these locations, analog UHF TV is easily received today without the use of outdoor antennas. In fact, the results indicated that DTV is not only unable to replicate today's coverage but appears to fall far short of being easily received by the consumer in areas of high signal strength.

The tests were designed to confirm the CEMA published representations that, if a CCIR 3.5 grade or better analog picture could be received inside the home, a DTV picture would also be available using typical indoor antennas (ref. CEMA INTERNET SITE). If DTV was not received, then a large directional outdoor type antenna was brought into the home or office to attempt to receive DTV.
In ALL of the indoor locations investigated, good UHF NTSC pictures were available but DTV was NOT received on the same simple antennas. In most locations the large antenna (stacked array of four dipoles backed with a reflector) was also unable to provide useable signals to the DTV receivers. In short, the test showed that DTV could NOT replicate today's analog TV coverage inside of typical consumer homes that were located within the station's Grade A or City Grade contours. The 8VSB transmission system, which was designed for outdoor reception, was just not capable of overcoming the multi-path distorted signals found inside of homes and offices.

The effect of these tests seems to indicate that DTV coverage is going to be significantly less than today's analog coverage when the consumer tries to receive it using available reception techniques. It also raises questions as to the viability of the representations, put forward by CEMA and the ATSC to both the professional and consumer communities, as to the ability of DTV to penetrate into the market.

The next question to be asked... Is there another technical solution for receiving the 8VSB transmission standard? At Sinclair, we are not sure. One option may be to wait for the development of a so-called "active" antenna. To help answer the question, the test procedure called for the indoor use of a large directional dipole array in an attempt to recover the digital data. This effort was largely unsuccessful, even with attempts to optimize the antenna position. This result raises doubts as to the effectiveness of any small active antenna design that might emerge in the future.

It has been over five years since the 8VSB system was evaluated and adopted. Perhaps something better is now available. Recent reports from Europe seem to indicate that the COFDM system deployed there has demonstrated very robust performance inside of buildings and in multi-family dwellings. The transmission standard is a tiny part of the ATSC standard and a change to it would not require another "grand alliance" effort. In fact, the very same receiver manufacturers who are making 8VSB are also making COFDM receivers now. The change to the transmitter plant would also be a minor effort requiring only a change in the modulator. The early consideration of COFDM, by ACATS and the ATSC, was done at a time when the technology was immature and not representative of today's commercial implementation.

Thus it seems that there may be another system worth looking at now. Certainly the demonstrations of COFDM as a transmission system for ENG applications, by several large companies, highlights its potential, albeit at a reduced data rate. A recent FCC ruling that allows COFDM to be used at MMDS frequencies also seems to recognize that the technology has merit. In fact, the use of COFDM for MMDS may revolutionize that industry by providing a solution to the "line of sight" problem.

The loss of indoor reception for our City Grade and Grade A viewers is an unwelcome and unacceptable outcome of the conversion to DTV. We at Sinclair believe that conclusion should be true for all broadcasters. Our birthright and unique position in our communities is based on our ultimate ability to reach our audiences without the use of wires, to provide free entertainment and information. We are a wireless service. It is implicit in the word "broadcasting".

The CEMA model for DTV reception that requires a rotatable outdoor antenna at 30 feet above the ground is a bankrupt concept based on a 1950s view of the world. The proof of that lies in the reality of multiple TV set households. Does the consumer have to install a separate antenna with its own rotator for each set in the home in order to watch more than one channel at a time? Will the consumer give up channel surfing? Under the present scheme that will be the outcome. Certainly we can and must do better!

Recent tests by CBS in New York, reported in the trades, continue to claim good results with outdoor antennas, while not offering any comparative data about the ease of indoor reception with respect to today's analog signals. In fact, the report that good DTV reception was achieved in many cases only by pointing the antenna away from the station and receiving a bounced signal off of a building seems to indicate the delicate and unique nature of the received path. We can only wonder, what would be the situation in a multi-station market?

For those of you who want to rely on cable and satellite as the ONLY means of reaching your future audiences, I can only ask you to consider your first cable carriage negotiations after the return of the analog spectrum. Remember, the 85% penetration rule for the turn off of today's stations can be reached by counting all the digital sets connected to cable in your market. In that not too distant world we could be reduced to nothing more than just another cable program provider in the midst of many.

In an attempt to determine if a better option is available to us, Sinclair is prepared to sponsor a side by side test of the 8VSB and the 6Mhz COFDM-based DTV transmission systems using similar data rates. It is hoped that this effort will find wide interest and support within the broadcast community. The test can be run very soon after NAB and will be open for all to witness. It is our hope that such an effort will allow the broadcast community to actually see the true comparative performance of the systems we are mandated to install and be able to support the best one for our future.

If you are interested in supporting this effort with your intellectual resources or want to find out more about the Philadelphia test results, please contact me or David Smith directly at Sinclair. If you want a personal briefing, that might be possible during the NAB convention.

Thank you for your past support on the vital issues confronting our industry like last year's power issue that resulted in a favorable resolution for the UHF industry. Unlike the power issue, this is not an intra-broadcast issue. It is something that every broadcaster should want to have resolved as it effects both the VHF and UHF communities equally. This is a broadcast industry issue and a reflection of our future ability to compete in an ever more difficult competitive world. It is not an engineering decision. It is a business decision.