World Headquarters, Beaverton, Oregon, USA
Z Technology measurement systems
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Address specific measurement needs
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acceptance
documentation
confirmation
identification
resolution
Our television customers
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Over 1800 stations are broadcasting
and maintaining DTV digital plants
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New transmission formats
New power levels
New channel assignments
New antenna locations
New government regulations
Cost and people constrained
Antenna patterns
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Not always as you would expect
6.5 miles from 1000’ AAT
Horizontal Gain
Oded Bendov / Krishna Praba, Television Engineering Handbook, Jerry Whitaker
Vertical Angle Gain
DSS5800 DTV measurement system
DSS5800 system features
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Measures multiple signals and formats
Maps signal coverage to GPS locations
Displays a full set of measured parameters
Graphs signal parameters over time
Records signal parameters to clear text files
Exports files for further analysis
Easily setup for reliable, automatic capture
DSS5800 DTV measurement system
Programmable field
strength meter
8VSB data demodulator
GPS Receiver
Power and
Distribution
Laptop Windowstm PC
AC
DC
DSS5800 DTV measurement system
Programmable field
strength meter
8VSB data demodulator
GPS Receiver
Power and
Distribution
Laptop Windowstm PC
AC
DC
DSS5800 DTV measurement system
Programmable field
strength meter
8VSB data demodulator
GPS Receiver
Power and
Distribution
Laptop Windowstm PC
AC
DC
DSS5800 DTV measurement system
Programmable field
strength meter
8VSB data demodulator
GPS Receiver
Power and
Distribution
Laptop Windowstm PC
AC
DC
Data is collected automatically
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Analog: records all setups, time, location,
direction of travel, peak power, antenna
factors, frequencies, etc.
Digital: adds wideband parameters;
integrated power, etc.
DTV systems add data from the digital
decoder; sync/eq locks, tap values, etc.
Clear text data files are easy to read and
export to other applications
Setup with the “Job Editor”
Sample the signal
Start data collection
Data files are clear-text
Data is easily formatted for
export to other applications
Drive testing
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Rapid accumulation of coverage data
• Calibrated measurement equipment
• 7 ft. antenna height, on roads
• Automatic capture and recording
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Identification of problem areas
• Relative to previous runs
• Poor signal coverage
• Changes in coverage
Live coverage mapping
Drive test considerations
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Equipment configuration
• Antenna, Power, Mounting, Calibration
• Convenience and Safety
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Environment
• Location, Obstructions, Reflections
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Operator interface
• Driver Distraction, Information Displays
• Setup & Automatic Collection of Data
Mobile test antennas
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Horizontal dipole
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W. K. Roberts/FCC balun design
3dB beamwidth approximately 78o
Magnet mount, ~24” above roof
Cal per ANSI C63.5 w/antenna factors for dBuV/m
Vertical sampling antenna
• Mag mount 1/4 wave vertical
antenna
• Not true to horizontal component
• Characterized
Multiple frequency testing
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Same band, one antenna
• Factory antenna factors
• Element length vs. frequency vs. factor
• Characterize for multiple frequencies
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Multiple Antennas
• Power combiners
• Filters
• System characterization
Multiple antennas
VHF
UHF
LP Filter
HP Filter
Power
Combiner
dBuV/m
VHF ant correction factor + cable loss + LPF loss + Combiner loss + cable loss = VHF Antenna Factor (sys)
UHF ant correction factor + cable loss + HPF loss + Combiner loss + cable loss = UHF Antenna Factor (sys)
Add antenna factor plus cable loss to receiver reading in dBuV
to convert to field intensity in dBuV/Meter.
Measurement repeatability
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Equipment certification
• NIST traceable antennas, cables, field
strength meter
• Secondary reference
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Equipment setup
• 30 ft. antenna height vs. vehicle rooftop
• Antenna factors recorded with data
The Drive Test
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Set up the “job” for signal types and
frequencies
Click F1 “Sample” to check the reception
Click F3 “Record Continuous”
Drive until direction changes more than
~30 degrees; stop and adjust antenna
direction
Click F4 “Stop Measurements”
Take a break and look at the data
Analyzing the data
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Real-time map
plotting
• Colored trail of dots
for any parameter
• Plots value as a
color for each GPS
location measured
• Color may be
automatically or
manually scaled
Analyzing the data
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Map oriented data
• Colored trail of dots
for any parameter
• Tool-tip displays
selected value for
selected location
• Right-click for all
data taken at that
location
8VSB data parameters
On-site testing
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Problem resolution
Difficult locations
Sniff out problems
Using customer
antennas
Site suitability
8VSB signal w/outdoor antenna
DTV signal with indoor antenna
Signal Level
(voltage)
At Cursor Position
(frequency)
8.8 dB
0.33 MHz (freq)
20 Log(.38)=8.4 dB
Main Tap normalized
To 100%
3 uS
(time)
38% of Main Tap Energy
(voltage)
Example Case: One major reflection at 3 uS
causes a .33 Mhz ripple on the Spectrum Display
Percent
Reflection
(Voltage)
At Cursor
position
(Delay)
Spectrum & S/N time plots
Time plots of multiple parameters
Low vs. full power dtv signals
Outdoor antenna not much help
RF signal measurement products
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Systems designed to meet
specific industry needs
• digital and analog RF field
strength measurements
• automatic signal coverage
mapping
• 8VSB/DVB-T demodulated
data analysis
Portable test systems
• Custom Design
– Telescopic Masts
– Log Periodic Antennas
– Compass for Antenna
Pointing
– Manual or Electric
Rotation
– Rack-mount Packages
– 12VDC or AC Mains
Operation
Learn more about our systems
Z Technology, Inc.
14950 NW Greenbrier Parkway
Beaverton, Oregon 97006 USA
Tel: 503.614.9800 Fax: 503.614.9898
www.ztechnology.com
sales@ztechnology.com
NAB Contacts:
John Purdy, Jim Zook