TV Spectrum Repack & ATSC 3.0 - Jay Adrick - Technology Advisor - NAB Show New York
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TV Spectrum Repack & ATSC 3.0 Jay Adrick - Technology Advisor Cindy Cavell – Broadcast Consultant GatesAir Cavell Mertz TV 2020
Spectrum Clearing Impact For 84 MHz Estimated Range LOW High Eligible UHF Stations 1706 1706 Stations Eliminated to Clear Spectrum 222 249 Stations Remaining On Channel 433 262 Stations Required to Repack 1020 1164 • Estimated ranges based on DTC Study and FCC’s simulations TV 2020
Repack Timeline Event FCC Runs Post-Auction Channel Optimization Once Final Stage Rule is Satisfied FCC Sends Confidential Letters With Post-Auction After Optimization is Channel Assignment Complete FCC Issues Channel Reassignment Public Notice Once Forward Auction is Complete TV 2020
Repack Timeline Event File CP for Modified Facility 3 months after reassignment PN Post-Auction Filing Windows (channel changes or After staff processes initial expanded facilities) applications • Window 1: Stations unable to meet technical parameters in reassignment PN • Window 2: All other stations assigned to new channels Construction Deadline Up to 39 mos. after reassignment PN TV 2020
Will Stations Not Changing Channels Be Impacted? • Possibly if stations…. • Share a tower • Have stacked antennas • Operate on a shared antenna and transmission line …with a station that must change channel • FM stations on a shared tower with TV Additional issues • Who will pay the cost for accommodating these stations? Not covered by Repack compensation • Potential increased interference from neighboring stations (0.5% of population per other station) TV 2020
Open Issues for Full Power/Class A Stations • How to Repack Broadcasters Within 39 Months – Can broadcasters (and their lawyers and engineers) prepare and submit CP applications and reimbursement requests within 39 months? – Is FCC’s phased approach realistic? – Case-by-case exceptions for stations that can’t meet deadlines? • Whether $1.75 Billion Will Cover Reimbursement Expenses – How will FCC distribute funds if there is a shortfall? – How will FCC determine what expenses are “reasonable”? • How to Account for Loss of Translators TV 2020
Impact on Broadcast Technical Resources • Large demand on consulting engineers • Structural analysis • Transmitter installers • Tower crews – new towers and antenna installation • May need to look for alternative resources • Projects may delayed by many factors TV 2020
A Typical DTV Transmission Plant • Basic transmission system blocks: ANTENNA • Transmitter, comprising: • External RF Items: • Exciter • Mask Filter • Amplifier • RF Combiner • Power Supplies • Transmission line • Control • Antenna • Cooling System TRANSMITTER Other transmitter(s) (if applicable) FILTER RF POWER RF MASK TRANSMISSION RF EXCITER COMBINER LP AMPLIFIER FILTER LINE Program Material (Video, Audio, Power Supplies Data) Control Cooling TV 2020
What’s Impacted by Repack? • If moving from an affected channel to a new one: ANTENNA • The following items will need to be looked at for retune Very Likely or replacement: TRANSMITTER Possibly Other transmitter(s) (if applicable) FILTER RF POWER RF TRANSMISSION RF EXCITER VeryAMPLIFIER MASK COMBINER LP FILTER LINE Program Likely Material 100% (Video, Audio, Power Supplies Likely Data) Control Cooling Very Likely TV 2020
Coverage Replication • OET-69 “dipole factor” $ " ' " = $ (4 )' 1 MW ERP AT CH49 WILL BE ALLOCATED 687 KW ERP AT CH 25 TV 2020
Replicate with Same Size Antenna Channel 51 Channel 24 TFU-30JTH-R O4 TFU-22JTH-R O4 Ø10.75” Pipe Ø10.75” Pipe 27 Gain 20 Gain 45.2 ft. 43.5 ft. (EPA) = 42.4 ft2 (EPA) = 45.0 ft2 W = 3800 lbs. W = 3600 lbs. SAME SIZE AND WINDLOAD – LOWER GAIN TV 2020
Replicate with Same Gain Antenna Channel 51 Channel 24 TFU-30JTH-R O4 TFU-30JTH-R O4 Ø10.75” Pipe Ø14” Pipe 27 Gain 27 Gain 45.2 ft. 58.3 ft. (EPA) = 42.4 ft2 (EPA) = 68.7 ft2 W = 3800 lbs. W = 7000 lbs. REQUIRES LARGER HEAVIER ANTENNA TV 2020
Replicate with Lower Gain Antenna If the tower that the antenna is currently on will NOT support the length and/or weight of a larger antenna without significant modifications, The FCC may allow the use of a lower gain antenna and a higher Transmitter Power Output to make up the ERP. TV 2020
Staying On Air During Repack • Initial equipment and services requirements may be driven by factors such as the type of transition…ad hoc vs market or regional coordinated • Your station will likely need a temporary antenna, transmission line and replacement or standby transmitter to maintain service while rebuilding the primary transmission system TV 2020
Staying On Air During Repack • It may be possible to choose an interim site that could be utilized not only as a replacement site for the main antenna while it is being replaced and as a future site that could be used in conjunction with a future Single Frequency Network (SFN). TV 2020
Repack and Preparing for ATSC 3.0 • Two major considerations during repack will impact your future transition to ATSC 3.0 • Purchasing the right antenna • Purchasing the right transmitter TV 2020
ATSC 3.0 and Antenna Replacement • ATSC’s Physical Layer was designed to reach mobile, portable, handheld and receivers with indoor antennas. • Signal density, lower C/N and improved error correction • All stations should consider adding V Pol if replacing an antenna during repack…stations may have to add some of their own money to the purchase • Substantial longer term savings gained by not having to replace an antenna (all at the station’s expense) later TV 2020
ATSC 3.0 and Transmitter Replacement Three considerations when selecting a replacement transmitter during repack • Can the exciter(s) upgraded to accommodate ATSC 3.0? • Will the new transmitter support the additional 2dB of PAPR? • Will the new transmitter support additional TPO for additional V-pol? TV 2020
ATSC 3.0 and Transmitter Replacement Stations will likely have to add capital to the FCC reimbursement if the replacement is higher power than the current TX (unless higher power is needed to replace a lower-gain antenna) • Longer term savings from not having to replace the transmitter when transitioning to ATSC 3.0 TV 2020
Single Frequency Networks (SFN) aka Distributed Transmission System (DTS) • DTS uses “big stick/smaller fill-ins” • SFNs can be more “cellular” in nature – several medium-power sites • ATSC 3.0 lends itself well to SFNs because of the modulation scheme (OFDM) • Possibility to fill in nulls in the coverage caused by terrain or antenna nulls. TV 2020
Single Frequency Networks (SFN) aka Distributed Transmission System (DTS) • SFN systems use a series of on-channel “boosters” • Coverage from all sites cannot go outside the post-repack FCC- determined coverage area • May be able to use smaller SFN sites to recover areas lost when fill-in translators are lost to the repack (doesn’t really address extended translators in places like the Pacific NW) TV 2020
Why are SFNs Important? • Not only to get the signal to the entirety of the station’s protected contour, but to get GOOD signal to as much of the contour as possible. • Portable indoor devices and outdoor mobile devices need higher signal strength to receive well. • This is a great way to achieve best overall signal density across the entire coverage area TV 2020
Using Distributed Transmission to Increase Signal Availability WRC-DT (ATSC 3.0 1 MW ERP on Ch. 36) TV 2020 23
WRC-DT Adding 4 SFN Distributed Transmission Sites TV 2020 24
WRC-DT Adding SFN Combined Power (closeup) TV 2020
Condition Population @ 80 dBµV/meter Single transmitter (DC) 2,819,869 Combined (all five transmitters) 4,596,775 Percent gain: 63% Population served by exactly 246,442 two transmitters: Population served by exactly 1,497,278 three transmitters: Population served by exactly 1,763,638 four transmitters: TV 2020 26
Using SFN to Save Spectrum Example: Iowa SFN Ch. 36 4m Receive Height TV 2020 27
ATSC 3.0 Transition& Implementation Guide Available for Download Executive Summary & Detailed Technical Guide TV 2020
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