Overview of MaxxCasting by Geo-Broadcast...
Transcript of Overview of MaxxCasting by Geo-Broadcast...
Overview of MaxxCasting by Geo-Broadcast
Solutions John Kean
Senior Technologist NPR Labs – National Public Radio
Feb. 5, 2013
Background
Many are familiar with on-frequency repeaters (boosters) ◦ Most recall stories of unsatisfactory performance
Distorted audio (multipath)
Weak coverage
Interference to primary transmitter’s signal
◦ Some were problematic and were turned off
MaxxCasting
An FM repeater system, but that is where similarity ends…
Brings some new technologies to repeater networks to resolve performance issues ◦ Research into parameters that determine multipath interference
◦ Advanced geographic tools to intelligently design repeater networks
What is MaxxCasting?
Multiple lower-power, lower-height transmitters ◦ Placed strategically for desired zone
◦ Spaced optimally to provide coverage fill-in (major roadways, building penetration)
Frequency and modulation synchronized with primary transmitter using Harris Synchrocast®
Harris Broadcast Synchrocast®
NPR Labs’ Role
Design parameters ◦ RF Lab simulations of
primary transmitter and MaxxCast repeater signals Both mobile
(Rayleigh) fading and fixed signals
Process audio with professional broadcast hardware
Received with standard consumer car and home radios
NPR Labs’ Role
Listener tests ◦ Measure consumers’
opinions of MaxxCast design parameters
◦ Conducted at Towson University, designed and supervised by Dr. Ellyn Sheffield
◦ Listener keep-on, mean opinion scores
◦ 19,000 data points
Design Parameters
Listeners evaluated ◦ mono and stereo
modes
◦ Speech, music, voiceover
◦ Time-of-arrival between signals
◦ RF ratios between signals
◦ Compiled as tables, then surface charts
3
7
12
2004
816
Time (uS) D/U (dB)
Keep-On Scores - Primary Stereo - Booster Mono
90%-100%
80%-90%
70%-80%
60%-70%
50%-60%
40%-50%
30%-40%
20%-30%
10%-20%
0%-10%
Advanced RF Design Tool
Terrain-sensitive analysis of field strength
High-resolution Shuttle Radar Topography – city block level
Able to consider signals from multiple MaxxCast transmitters (nodes)
Population counts with US 2010 Census data
Current Coverage
Escondido Coverage
6-Node Maxxcast Network Added
Escondido Coverage 6-Node MaxxCast
KPRI(FM), Population Example
Indoor Service (65 dBu @ 2m)
Portable Service (74 dBu @ 2m)
Present Station 913.137 410,749
With Escondido MaxxCast
1,046,797 526,915
change 133,660 (+14%) 116,166 (+28%)
Notes: MaxxCast population counted after deduction for interference 2010 U.S. Census
Interference Effects of 6-Node MaxxCast
Interference Effects of 6-Node MaxxCast
GBS MaxxCasting Why Do Stations Need MaxxCasting?
There are 94 million persons in the top 15 Arbitron metro markets
Those top 15 markets have radio revenue of $4.8 billion
Many of those markets full signal stations are not covering up to 15% of the markets’ potential listeners
Therefore, those stations are not reaching 14 million potential listeners
Therefore, those Stations are missing out on $.720 billion in potential revenue
How much of those potential revenues should belong to you?
INCREASE COVERAGE, LISTENERS, RATINGS AND REVENUE WITH MAXXCASTING