The one glaring contrast between the DTV conversion and the plan for the pending channel re-pack is that there will be no simulcast period. It is channel A today and channel B tomorrow. That changeover has to be carefully planned due to potentially serious consequences. Thus the choice of re-using existing, re-tuning existing or new RF systems, transmission line and antennas is very important. Some major variables that go into these choices are availability of space, tower loading, RF component bandwidth, transmission line bandwidth and antenna bandwidth. Availability of skilled people to perform re-tuning and tower work cannot be ignored. This presentation will outline some transition scenarios and relevant antenna and RF choices and their relevant time-lines.

1. TV Repack – RF & Antenna
Transition Strategies
K e it h Pe lle t ie r, O c t obe r, 2 0 1 5

2. • Timeline
• Towers
• Antennas
• Transmission Line
• RF Systems
• Transition Scenarios
O ve r v i e w
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3. Repack / Transition Timeline
≥ 9 months
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4. Clearing Goal for 84 MHz
Rank DMA Size Ave # cleared Std Dev
1 NewYork, NY 23 10.2 1.2
2 Philadelphia, PA 23 8.3 1.3
3 Chicago, IL 21 8.1 1.3
4 San Francisco-
Oakland, CA
23 7.9 1.2
5 Boston, MA 17 7.1 1.2
6 Los Angeles, CA 27 6.9 0.98
Michael Kearns and Lili Dworkin
“A Computational Study of Feasible Repackings in the FCC IncentiveAuctions”
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5. Size of Repack ?
• 1600 to 1700 eligible stations
• 200 + need to move toVHF / channel share or go dark
• 1000 +/- 200 will be involved in the re-pack
• To clear channel 37 and above all states are impacted
except Alaska and possibly Wyoming
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6. Towers
• TIA-222 Rev G
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7. Towers
• TIA-222 Rev G
Ice
Wind Speed
Topography
Shape Factors
Get structural
analysis
Need detailed
site information
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8. Towers
• BasicWind Speed
• Antenna Elevation onTower
• Design Ice
• Tower Height
• Structure Class
• Exposure Category
• Topographic Category
• Height of Crest Above AverageTerrain
• Seismic Spectral Response Acceleration
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Site Criteria Needed for 222-G Antenna Proposal:
Much More Site Design Information is Required from
Broadcasters and/or Tower Engineers in 222-G
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9. Replication
• OET-69 “dipole factor”
ܲ௥ ൌ ܲ௧
‫ܩ‬௧‫ܩ‬௥ߣଶ
ሺ4ߨܴሻଶ
1 MW ERP AT CH49WILL BE ALLOCATED 622 KW ERP AT CH 25
‫ݔ‬ ൌ
ߣ௟
ߣ௨
ൗ
dB = 10 log x
2
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10. Towers – Antenna Wind-load
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Example: ChannelChanges
Channel 51
TFU-30JTH-R O4
Ø10.75” Pipe
27 Gain
(EPA) = 42.4 ft2
W = 3800 lbs.
45.2 ft.
Channel 24
TFU-30JTH-R O4
Ø14” Pipe
27 Gain
(EPA) = 68.7 ft2
W = 7000 lbs.
58.3 ft.
Same Gain Antenna Most Likely Not Required Due to Reduction in ERP 10

11. Towers – Antenna Wind-load
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Example: ChannelChanges
Channel 51
TFU-30JTH-R O4
Ø10.75” Pipe
27 (14.13dB)Gain
(EPA) = 42.4 ft2
W = 3800 lbs.
45.2 ft.
Channel 24
TFU-22JTH-R O4
Ø10.75” Pipe
20 (13.01 dB) Gain
(EPA) = 45.0 ft2
W = 3600 lbs.
43.5 ft.
Due to Reduction in ERP for CH 24, Same Transmitter can be used
1 MW ERP
Input Power = 37 kW
588 kW ERP
Input Power = 29.4 kW
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12. Antennas
• Pylon
• Narrowband
• Moving down in channel =
larger antenna (possibly)
• Some may allow adjacent
channel operation
• Less ERP required
at lower channels
to replicate
coverage
• Antenna not
necessarily longer
Replace
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13. Antennas
• Panel
• Broadband
• All stations have common
pattern
• Number of channels can be
limited by Power
• Owned by “vertical real-
estate” companies
• Broadcaster going dark may
open up space on panel
Re-use
• Joining a Panel
• FCC is not considering movingTx location during “re-pack” phase of the auction
• Application to move to a newTx site will be done post auction
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14. Multi-Channel Pylon
Example of a broadband slotted coaxial antenna design
WNYT Glens Falls, NY TLP-12W/VP-R (SP) channels 39 & 45
• 12 layer antenna with 4 way split
• Manufactured in ½” wall aluminum
• Elliptically polarized
Multi-sectional phase cancellation
LowerQ from thin wall
Leveraging Babinet’s principle
Channels 38 to 47 under 1.1:1 14

15. Coaxial line “stick” length, 3 MHz Guard Band
14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
20
19 ¾
19 ½
33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51
20
19 ¾
19 ½
Prohibited Channel per catalog
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16. Coaxial line “stick” length, 1.5 MHz Guard Band
14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
20
19 ¾
19 ½
33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51
20
19 ¾
19 ½
Prohibited Channel per catalog
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17. Transmission line
• Get a line sweep
• 6 1/8” line 20’ stick
length
• Ch 16 and 20 are OK
(<1.03:1)
Maybe Re-use
Sweep curtesy Ed Murlatt and associates
Channels 14 to 24
1.5 MHz Guard
3.0 MHz Guard
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18. RF Systems
• High Power RF System Components (25kW-80 kW)
WR1150
Ch44-69
WR1500
Ch18-48
WR1800
Ch14-17
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19. RF Systems
• High Power RF System Components
Coax to
Waveguide
Transitions
Narrowband
Replace
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20. RF Systems
• High Power RF System Components
Waveguide
Magic Tee
Combiner
New Slabs
Required
Re-tune
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21. RF Systems
• High Power RF System Components
Waffle Iron
Low Pass
Filter
Re-tune
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22. RF Systems
• High Power RF System Components
Constant
Impedance
Band-pass
Filter
Replace
Lower Channel Equals Larger Foot Print
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23. RF Systems
• High Power RF System Components
Waveguide
Switch
and Coaxial
Water-load
Re-tune
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24. RF Systems
• Medium Power RF System
Components (10kW-25 kW)
All components are broadband except
waveguide filter
Replace filter
Re-use all else
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25. RF Systems – Practical Considerations
• Field re-tuning not practical
– Limited qualified talent
– Some parts may need to be replace
• If you have a two tube system
– Re-tune one tube and operate into new CIF
– Send all other system parts for refurbishment
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26. Transition Scenarios
FLASH CUTFLASH CUTFLASH CUTFLASH CUT
• On air with original channel today
• On air with new channel tomorrow
GOT BACKUP?GOT BACKUP?GOT BACKUP?GOT BACKUP?
STAGEDSTAGEDSTAGEDSTAGED
NEED TEMPORARY
TRASMISSION FACILITY
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27. Transition Scenario’s - Staged
• Eliminates Nationwide Flash Cut
• Potential Relieve for Tower Crews
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28. If you have backup
• Operate off backup site while work is done at
main site to get ready for new channel
• Expect several months of back-up
operation
• Reliable back-up is important
• Back-up Antenna Must be Broadband
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29. Analog antenna still up?
• Operate off current digital channel
• Replace analog antenna (top mount)
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30. Currently no Aux Antenna ?
• New side mount on new channel
• Replace top mount post cut over
• Side mount becomes backup
• If re-using Tx line tower a top channel splitter can
be used to feed side mount
• Side mount can go at separate site and be used as
part of SFN or as backup post transition
• Put up side mount on current channel
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31. Candelabra ?
• Candelabra – New full power antenna
• New Stacked antenna with another broadcaster
• Space available by broadcaster going off air ?
• SpaceAvailable by Old AnalogAntenna
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32. Dual Channel Slot?
• Several dual channel slots went up during DTV conversion
• These are currently operating on one channel only
• Antenna, line and combiner are ready for broadcaster in
market repacked to that adjacent channel
• Operation from same aperture on adjacent channel will
mitigate interference
• Apply to FCC to change broadcast site
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33. Panel?
• Join existing or new panel as tenant
• Space made available by broadcaster going off air ?
• Will require combiner work
• New manifold combiner
• Possible broadband port addition or module
replacement in CIF
• Vertical real estate company owns and upgrade hardware,
broadcasters lease
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34. New Multi-Channel Pylon
9 % = ch14-21 (8 channels)
ch30-38 (9 channels)
ch34-42 (9 channels)
ch42-51 (10 channels)
Channels 38 to 47 under 1.1:1
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35. ATSC 3.0
• AddV-Pol to help mobile reception
• Single Frequency Network (SFN) topology
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36. Conclusions
• A temporary or back up transmission facility will be
required
• Antennas will most likely have to be replaced
• Good chance that transmission line can be re-used
• Some RF system components can be re-used
• Don’t plan on field re-tuning (resource limited)
• Least expensive option would be to move to existing
transmission site if it is available in the market
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