VHF Reception Panel Topics Background- Television B in addition to s Background – Channel Width in addition to Fractional B in addition to width Background – Antenna Fundamentals

VHF Reception Panel Topics Background- Television B in addition to s Background – Channel Width in addition to Fractional B in addition to width Background – Antenna Fundamentals www.phwiki.com

VHF Reception Panel Topics Background- Television B in addition to s Background – Channel Width in addition to Fractional B in addition to width Background – Antenna Fundamentals

Bergholdt, Brad, Freelance Columnist has reference to this Academic Journal, PHwiki organized this Journal VHF Reception Panel William Belt, Consumer Electronics Association Greg Best, Greg Best Consulting Charles Cooper, duTreil, Lundin in addition to Rackley Kerry Cozad, Dielectric Communications Ross Heide, Cohen, Dippell in addition to Everist Ralph Hogan, Society of Broadcast Engineers Jeff Johnson, Gannett Dave Young, Antennas Direct Victor Tawil, MSTV Kelly Williams, NAB Topics Background/Fundamentals Channel in addition to b in addition to width Antennas Transmitters RF environment VHF reception problems Response to FCC questions General observations Background- Television B in addition to s 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) VHF BROADCAST FREQUENCY BAND PLAN

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Background – Channel Width in addition to Fractional B in addition to width DTV Channel Width = 6 MHz Fractional B in addition to width = 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 uni as long as m amplitude in addition to linear phase across channel Problematic with compact receive antennas (electrically short antenna) Background – Antenna Fundamentals Size Inversely proportional to frequency Antennas are generally inefficient when less than resonant size (electrically short) Impedance B in addition to width (VSWR) Range of frequencies over which the antenna is impedance matched to transmission line VSWR < 3:1 desirable as long as receive antennas Electrically compact antennas have higher VSWR in addition to either narrow impedance b in addition to width or low efficiency Background – Antenna Fundamentals Directivity in addition to 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 per as long as mance due to mismatch Transmitting Antenna Design Considerations B in addition to Radiator Type Azimuth Pattern Elevation Pattern Polarization Ch 10 TF-12 Gain ~ 12x Ch 5 TF-6 Gain ~ 6x Ch 20 TFU-30 Gain ~ 26x Antenna Length Comparison 72.9 ft 83.0 ft 60.9 ft High B in addition to VHF 6 Bay Panel Antenna 30.9 ft Typical VHF Antenna Parameters For panel antennas, weight of support tower not included Optimum tower face size as long as panels: L: 10.5 ft; M: 9.2 ft; H: 3.4 ft Background – Consumer Antenna Consumers avoid large antennas due to aesthetic reasons in addition to Code in addition to Covenant Restriction/Deed Restrictions Few Low VHF stations, no consumer dem in addition to No retail option due to revenue density requirements, return rates, shipping costs Multiple televisions in different rooms pose additional problems Background – Smart Antennas CEA909 / 909B Smart Antenna st in addition to ard 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 in addition to those were flawed! No market potential until enhanced in addition to included in flat panel DTVs 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 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% 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 Low VHF Environment Evidence suggest Low-B in addition to VHF has reception issues using indoor in addition to 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 Impulse Noise (ch. 6) 75 MHz 85 MHz 95 MHz 10 dB/div References Technical Papers in addition to Report “Reasons Channels 2 through 6 Are Not Commercially Viable as long as 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 in addition to Cincinnati.” NAB/MSTV Report January 2001 Book by Edward Skomal, Man-made Noise, Van Nostr in addition to , 1972 Articles by G. Hagn, A.D Spaulding, D. Middleton, W.R Lauber & J.M Bertr in addition to on Man-made Noise Books by A. U. H. Sheikh on Man-made noise, 1986 Articles by R. Dalke, R. Achatz & G. A. Huf as long as d, in addition to by J.D Parsons & A.U.H Sheikh, 1992 High VHF Environment Evidence presented suggest High-B in addition to 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 Impulse Noise Interference (Leaf Blower) Question no. 1 What changes could be made to VHF station transmissions (power, antenna in addition to 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 in addition to 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. Question no. 2 Have improvements in technology made it possible to improve consumer receiver/antenna per as long as mance, especially as long as indoor reception There are no “silver bullets” that will offer dramatic improvements in DTV as long as the VHF b in addition to s. Antenna size will continue to limit Low VHF improvements Improvements in computer simulation in addition to 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 in addition to High VHF b in addition to s. While antenna companies could realistically make additional incremental improvements in the size in addition to per as long as mance of Low VHF antennas, known physical laws preclude radical “order of magnitude” type improvements Question no. 2 (continued) Indoor reception problem is probably the best c in addition to idate as long as a high technology solution. Options such as smart antennas or the use of wireless repeater systems to make it easy as long as 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 as long as improving reception will occur in the near future. Question no. 2 (continued) In the receiver signal path, improvements to shielding, input filtering in addition to overload resistance in addition to linearity may help relieve some reception issues. None of these improvements however will offer the radical improvements necessary ensure good per as long as mance in the Low VHF b in addition to Reducing the spurious in addition to out of b in addition to emissions from consumers devices may help Bergholdt, Brad San Jose Mercury News Freelance Columnist www.phwiki.com

Question no. 3 Should the FCC set consumer antenna per as long as mance st in addition to ards Increase maximum power limits FCC should not set consumer antenna per as long as mance st in addition to ards. The universe of antenna characteristics including, gain vs frequency, VSWR, b in addition to width, in addition to other technical characteristics, coupled with the variability of the individual viewer’s geography, make a one size fits all per as long as mance st in addition to ard difficult in addition to impractical Need to st in addition to ardize descriptive terminology in addition to per as long as mance measurement st in addition to ards could be helpful to manufacturers, retailers in addition to consumers Question no.3 (continued) Should the FCC set consumer antenna per as long as mance st in addition to ards Increase maximum power limits Yes, increasing maximum power limits will improve reception, especially at High VHF as long as indoor reception. Power increases however increase the interference distance, in addition to are limited by physical, in addition to practical constraints Question no. 4 What options are available as long as improving TV service in the lower VHF b in addition to There are currently very few, if any, avenues as long as improving TV service in the Low VHF b in addition to . Practical power increases will marginally improve reception, but given the increased RF noise level in the b in addition to , in addition to physical limitations on the size in addition to efficiency of the transmit in addition to receive antennas, the increase is not sufficient to compensate as long as these deficiencies Reducing the spurious in addition to out of b in addition to emissions from consumers devices may help

Question no. 5 What is the most optimal use of the lower VHF b in addition to There are several options as long as sharing the Low VHF b in addition to with existing broadcast licensees. Options include: Designate it as a Spectrum Innovation B in addition to in addition to Permit alternative uses of Low-VHF b in addition to , such as: Long distance digital data back hauls Rural law en as long as cement in addition to local emergency responders Others, where use is to be determined by entrepreneurs Question no. 6 How should we be thinking about the VHF b in addition to 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 b in addition to , Group did not have an opinion on this question Final Thoughts Improvement in VHF reception is difficult in addition to limited by: The laws of Physics RF environment Practical limitation of transmitting in addition to receiving equipment design

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Bergholdt, Brad Freelance Columnist

Bergholdt, Brad is from United States and they belong to San Jose Mercury News and they are from  New Almaden, United States got related to this Particular Journal. and Bergholdt, Brad deal with the subjects like Automobiles; Automotive Repairs and Service Stations

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