TV Spectrum Repackingk4co.org/MiscDocuments/RepackOverview2019.pdf · FCC Auction Status Dashboard $10 B $20 B. New UHF Band Plan •TV UHF spectrum reduced to channels 14 - 36 •

TV Spectrum Repacking

Jay AdrickConsulting Engineer Cavell Mertz and Associates

FCC Auction Status Dashboard

$10 B $20 B

New UHF Band Plan

•TV UHF spectrum reduced to channels 14 - 36• 600 MHz Wireless spectrum channelized into 5 MHz pairs•TV service remains 6 MHz channels •Duplex gap between wireless uplink and downlink•Guard band spectrum between services

WHITE – TV Channels Gray – Guard bands Blue – Wireless Channels

How Many Stations Directly Impacted?

Spectrum Recovered

MHz

Highest Remaining TV

Channel

Full PowerStations

Class AStations

Total Stations Directly

Impacted*

84 36 593 144 737

Directly impacted stations are those currently assigned to spectrum that is to be cleared for wireless services

*Some participated in the auction, thus reducing the number of directly impacted stations

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

Spectrum Clearing Impact For 84 MHzEstimated Range

Estimated ranges based on DTC Study and FCC’s simulations* Numbers do not include the impact on Canadian stations

Action as a Result of the Spectrum Auction Number

Stations Eliminated (Not Including Channel Sharing)* 145

Stations Moving From UHF to VHF* 30

Stations Relocated Within the UHF Band* 917

Stations Relocated Within the VHF Bands* 70

Canadian Stations Forced to Relocate 62

TV Repack Report Card

* US stations Only

17 LB13 HB

Are Stations Not Changing Channels Impacted?• Yes if stations….

• Share a Tower• Have stacked tower top antennas• Operate on a shared antenna and

transmission line …with a station that is forced to change channel• FM stations on a shared tower with TV

• Additional issues

• Potential increased interference from neighboring stations (0.5% of population per other station)

Repack TimelineWe’re on the clock!

Construction Phases

April 13 April 2018 April 2019 April 2020 July 2020July 12

Repack Issues

Impact on Broadcast Technical Resources

• Large demand on consulting engineers time

• Structural analysis

• Transmitter installers

• Tower crews – new towers and antenna installation

• May impact planned radio projects.

• May need to look for alternative resources.

• Projects may get delayed.

A Typical DTV Transmission Plant• Basic transmission system blocks:

• External RF Items:• Mask Filter• RF Combiner• Transmission line• Antenna

ProgramMaterial

(Video, Audio,Data)

RFPOWERAMPLIFIER

RF

Control

Power Supplies

TRANSMITTER

Cooling

MASK FILTER

COMBINER TRANSMISSION LINE

Other transmitter(s)(if applicable)

ANTENNA

RFEXCITER

LP F

ILT

ER

• Transmitter, comprising:• Exciter• Amplifier• Power Supplies• Control• Cooling System

What’s Impacted by Repack?

ProgramMaterial

(Video, Audio,Data)

RFPOWERAMPLIFIER

RF

Control

Power Supplies

TRANSMITTER

Cooling

MASK FILTER

COMBINER TRANSMISSION LINE

Other transmitter(s)(if applicable)

ANTENNA

RFEXCITER

LP F

ILT

ER

Very Likely

Very Likely

Likely100%

Very Likely

Possibly

• If moving from an affected channel to a new one:• The following items will need to be looked at for

retune or replacement:

Transmitter Replacement is Likely• Most transmitters are ~10 - 20 years old

• Older UHF transmitters designed around band segments

• May require new amplifier pallets, combiners or driver modules - availability of obsolete devices unlikely

High Power RF Output Systems• Waveguide bands, generally: • WR1800, Ch’s 14-21• WR1500, Ch.’s 18-49• WR1150, Ch.’s 46-69

• Above isn’t exhaustive. Waveguide also has prohibited line lengths on a per channel basis. Consult Manufacturer.

• Mask Filter Cavities are per Channel• In general, a new RF system will be needed

Channel Compatibility of Coaxial Transmission Line

3 MHz guard band dates back to analog with aural carrier 0.25 MHz from band edge. DTV signal enables a relaxing in guard band requirements.

Tower Structural Analysis• TIA-222 Rev G

• Ice

• Wind Speed

• Topography

• Shape Factors

• Tower owner will need to get a structural analysis

Channel change effects• Higher channel moving down-band

• Less power for equivalent coverage

• Larger antenna

• Lower channel moving up-band

• If station was maximized at 1 MW ERP, likely that coverage will be lost

• Smaller antenna

• OET-69, F(50,90)

• dBu

• Example

• Moving from Ch. 51 to Ch. 24

2.3 dB

•

Dipole Factor, equivalent coverage

Replicate with Same Size Antenna

Channel 51TFU-30JTH-R O4Ø10.75” Pipe27 Gain14.1 dB

(EPA) = 42.4 ft2

W = 3800 lbs.

45.2 ft.

Channel 24TFU-22JTH-R O4Ø10.75” Pipe20 Gain13 dB

(EPA) = 45.0 ft2

W = 3600 lbs.

43.5 ft.

Similar size and wind load.Lower gain, but still more than dipole factor -> Could re-use transmitter if it has been determined that it is feasible to do so.

Replicate with Same Gain Antenna

Channel 51TFU-30JTH-R O4Ø10.75” Pipe27 Gain

(EPA) = 42.4 ft2

W = 3800 lbs.

45.2 ft.

Channel 24TFU-30JTH-R O4Ø14” Pipe27 Gain

(EPA) = 68.7 ft2

W = 7000 lbs.

58.3 ft.

Requires larger, heavier antenna.

Cincinnati Market RepackOctober 18, 2019

• 1947 Analog channel 4• 1952 Analog channel 5• Pre-repack DTV channel 35• Post repack DTV channel 20• Virtual channel 5

WLWT

• 1949 Analog channel 7• 1952 Analog channel 9• Transition DTV channel 10• Pre-repack DTV channel 35• Post repack DTV channel 20• Virtual channel 9

WCPO-TV

• 1949 Analog channel 11• 1952 Analog channel 12• Transition DTV channel 31• Pre-repack DTV channel 12• Post repack DTV channel 12• Virtual channel 12

WKRC-TV

• Analog channel 19• Pre-repack DTV channel 29• Post repack DTV channel 15• Virtual channel 19

WXIX-TV


WCET-TV


WSTR-TV


WPTO-TV


WCVN-TV

• Original Analog channel 25• Later Analog channel 38• Original DTV channel 47• Repack Transition channel 20• Post repack DTV channel 28• Virtual channel 25

WBQC-CD


WYDC-CD

• First Analog channel 39• Second Analog channel 38• Third Analog channel 25• Pre-repack DTV channel 38• Post repack OFF Air• Virtual channel 25

WOTH-TV