1. VHF Reception Panel William Belt, Consumer Electronics Association Greg Best, Greg Best Consulting Charles Cooper, duTreil, Lundin and Rackley Kerry Cozad, Dielectric Communications Ross Heide, Cohen, Dippell and Everist Ralph Hogan, Society of Broadcast Engineers Jeff Johnson, Gannett Dave Young, Antennas Direct Victor Tawil, MSTV Kelly Williams, NAB

2. Topics  Background/Fundamentals Channel and bandwidth Antennas Transmitters RF environment VHF reception problems  Response to FCC questions  General observations

3. Background- Television Bands Low VHF (channels 2 to 6)  Frequency: 54 to 88 MHz  Wavelength: 5.55 to 3.41 meters (18.2 to 11.19 feet) High VHF (channels 7 to 13)  Frequency: 174 to 216 MHz  Wavelength: 1.72 to 1.39 meters (5.64 to 4.56 feet) 3 VHF BROADCAST FREQUENCY BAND PLAN

4. Background – Channel Width and Fractional Bandwidth DTV Channel Width = 6 MHz Fractional Bandwidth = ratio of channel width to center frequency Low VHF Channel 2 FB = 10.5% VHF Channel 6 FB = 7.1% High VHF Channel 13 FB = 2.8%  Difficult to maintain uniform amplitude and linear phase across channel  Problematic with compact receive antennas (electrically short antenna) 4

5. Background – Antenna Fundamentals  Size – Inversely proportional to frequency – Antennas are generally inefficient when less than resonant size (electrically short) 5  Impedance Bandwidth (VSWR) – Range of frequencies over which the antenna is impedance matched to transmission line – VSWR < 3:1 desirable for receive antennas – Electrically compact antennas have higher VSWR and either narrow impedance bandwidth or low efficiency

6. Background – Antenna Fundamentals  Directivity and Gain Measure ability of antenna to focus energy in a particular direction as compared to a reference dipole antenna Its possible to have high directivity (good focusing) but poor performance due to mismatch 6

7. Transmitting Antenna Design Considerations  Band  Radiator Type  Azimuth Pattern  Elevation Pattern  Polarization 7

8. Ch 10 TF-12 Gain ~ 12x Ch 5 TF-6 Gain ~ 6x Ch 20 TFU-30 Gain ~ 26x Antenna Length Comparison 72.9 ft 8 83.0 ft 60.9 ft

9. High Band VHF 6 Bay Panel Antenna 30.9 ft 9

10. Typical VHF Antenna Parameters Ant TypeChannelsRMS GainHt (ft) (H 2 ) Weight (lbs) TF-6L2-36101.015,000 TF-6M4-6682.810,400 TF-6H7-136.537.33,200 TF-12H7-131272.98,200 Panel 6L2-3695.817,380* Panel 6M4-6675.113,600* Panel 6H7-13630.02,600* Panel 12H7-1311.860.05,300* *For panel antennas, weight of support tower not included Optimum tower face size for panels: L: 10.5 ft; M: 9.2 ft; H: 3.4 ft

11. Background – Consumer Antenna Consumers avoid large antennas due to aesthetic reasons and Code and Covenant Restriction/Deed Restrictions Few Low VHF stations, no consumer demand No retail option due to revenue density requirements, return rates, shipping costs Multiple televisions in different rooms pose additional problems 11

12. Background – Smart Antennas  CEA909 / 909B Smart Antenna standard – channel, direction, gain, polarization sent from receiver to enabled antenna – Most applicable to single set indoors – Does NOT solve Low VHF size issue! – Market penetration limited to coupon boxes only and those were flawed! – No market potential until enhanced and included in flat panel DTVs 12

13. Background - VHF Transmitters VHF Transmitters  Median licensed L-VHF Transmitter Power Output: 2.4 kW Effective Radiated Power: 7.25 kW  Median Licensed H-VHF Transmitter Power Output: 2.7 kW Effective Radiated Power: 19.75 kW 13

14. Background – VHF Transmitters To improve Low VHF reception by 20 dB would be impractical  Would need to increase the TPO to 240 kW  Over 20 cabinets using liquid cooled transmitters would be needed  AC to RF efficiency of around 20% To improve High-VHF Improvement of 10 dB would be doable, but difficult  Would need to increase TPO to 27 kW  3 cabinets using liquid cooler transmitter  AC to RF efficiency of approximately 20% 14

15. Background - VHF Station Statistics  Few Stations Operate in Low VHF 39 full power stations 2% of all DTV Stations Operate in Low VHF  Significant Number of Stations in High VHF 425 Stations 25% of all DTV Stations Operate in High VHF Since transition, 16 stations have received authorization to move to UHF channel 15

16. Low VHF Environment  Evidence suggest Low-Band VHF has reception issues using indoor and outdoor type receiving antennas Reception previously possible with analog facility on same RF channel DTV Reception Issues  Man-Made Electrical Noise  Atmospheric Noise  Inefficient Receiving Antenna  Transmit Power Increase to reduce the significance of these issues is 15 to 20 dB 16

17. Impulse Noise (ch. 6) 75 MHz 85 MHz 95 MHz 10 dB/div 17

18. References Technical Papers and Report  “Reasons Channels 2 through 6 Are Not Commercially Viable for DTV,” R. Evans Wetmore, P.E., Fox Technology Group, October 4, 2004  “Impact of Impulse Noise on DTV Reception at Low VHF,” Victor Tawil, Charles W. Einolf  “8-VSB/COFDM Comparison _Washington, Baltimore and Cincinnati.” NAB/MSTV Report January 2001  Book by Edward Skomal, Man-made Noise, Van Nostrand, 1972  Articles by G. Hagn, A.D Spaulding, D. Middleton, W.R Lauber & J.M Bertrand on Man-made Noise  Books by A. U. H. Sheikh on Man-made noise, 1986  Articles by R. Dalke, R. Achatz & G. A. Hufford, and by J.D Parsons & A.U.H Sheikh, 1992 18

19. High VHF Environment  Evidence presented suggest High-Band VHF has reception issues using indoor type receiving antennas DTV Reception Issues  Man-Made Electrical Noise  Inefficient Receiving Antenna  Transmit Power Increase to reduce the significance of these issues is likely on the order of 10 dB or more 19

20. Impulse Noise Interference (Leaf Blower)

21. Question no. 1  What changes could be made to VHF station transmissions (power, antenna and others) to improve the reception of their signals within their service areas?  Limited options to improve the VHF service: Low VHF  Power increases will help, but there are physical and practical limitations to achieve any significant reception improvement High VHF  Power increases will improve reception in some cases. However increase power can lead to increase interference to other stations. Implementation constraints will have to be taken into account.

22. Question no. 2  Have improvements in technology made it possible to improve consumer receiver/antenna performance, especially for indoor reception?  There are no “silver bullets” that will offer dramatic improvements in DTV for the VHF bands. Antenna size will continue to limit Low VHF improvements  Improvements in computer simulation and design technology have allowed incremental improvement of antennas. To date however, most of these incremental improvements have been realized in antennas that operate in the UHF and High VHF bands. While antenna companies could realistically make additional incremental improvements in the size and performance of Low VHF antennas, known physical laws preclude radical “order of magnitude” type improvements

23. Question no. 2 (continued)  Indoor reception problem is probably the best candidate for a high technology solution. Options such as smart antennas or the use of wireless repeater systems to make it easy for consumers to relay signals from compact outdoor antennas through the roof or a wall to indoor televisions. Development of solutions such as these often depend on the cooperation of the television manufacturers to implement a new feature or technology in their flat panel televisions. This is a difficult since television manufacturers are reluctant to add additional cost to their products. It is unlikely that any new technology for improving reception will occur in the near future.

24. Question no. 2 (continued) In the receiver signal path, improvements to shielding, input filtering and overload resistance and linearity may help relieve some reception issues. None of these improvements however will offer the radical improvements necessary ensure good performance in the Low VHF band Reducing the spurious and out of band emissions from consumers devices may help

25. Question no. 3  Should the FCC set consumer antenna performance standards? Increase maximum power limits?  FCC should not set consumer antenna performance standards. The universe of antenna characteristics including, gain vs frequency, VSWR, bandwidth, and other technical characteristics, coupled with the variability of the individual viewer's geography, make a one size fits all performance standard difficult and impractical  Need to standardize descriptive terminology and performance measurement standards could be helpful to manufacturers, retailers and consumers

26. Question no.3 (continued)  Should the FCC set consumer antenna performance standards? Increase maximum power limits? Yes, increasing maximum power limits will improve reception, especially at High VHF for indoor reception. Power increases however increase the interference distance, and are limited by physical, and practical constraints

27. Question no. 4  What options are available for improving TV service in the lower VHF band ?  There are currently very few, if any, avenues for improving TV service in the Low VHF band. Practical power increases will marginally improve reception, but given the increased RF noise level in the band, and physical limitations on the size and efficiency of the transmit and receive antennas, the increase is not sufficient to compensate for these deficiencies  Reducing the spurious and out of band emissions from consumers devices may help

28. Question no. 5 What is the most optimal use of the lower VHF band?  There are several options for sharing the Low VHF band with existing broadcast licensees. Options include :  Designate it as a Spectrum Innovation Band and Permit alternative uses of Low-VHF band, such as:  Long distance digital data back hauls  Rural law enforcement and local emergency responders  Others, where use is to be determined by entrepreneurs

29. Question no. 6  How should we be thinking about the VHF band in general – what is the best use of that spectrum?  Low VHF  The answer is highlighted in question no.5  High VHF Other than the current use of the band, Group did not have an opinion on this question

30. Final Thoughts  Improvement in VHF reception is difficult and limited by: The laws of Physics RF environment Practical limitation of transmitting and receiving equipment design

31. Thank You