Mapping of FM

and HD Radio Coverage

Brian Casey, Leandro Franca, and Thomas Shanks

April 22, 2009

2

Project SummaryProject Summary

• Measure radio station coverage through:

– RF Field Strength (conventional method)

– Signal-to-Noise Ratio of audio (what listeners actually hear)

• Provide maps of data

• Determine statistical information of SNR

• Compare results with and without HD

3

Block Diagram of SystemBlock Diagram of System

•BLUE 75Ω coax w/ F connector•RED 50Ω coax w/ UHF connector•GREEN Data connector•BLACK Audio cable RCA to 1/8”

Antenna

BPF88-108MHz

25dB AmpNF~5.6

SpectrumAnalyzer

HD RadioHD Radio

Analog FM Radio #1

Analog FM Radio #2

Audio Input (PC)

ComputerAnalyzingSoftware

GPS

DIOS

plitt

er

Magnetic MountWhip

4

Car and hardware photosCar and hardware photos

5

Software DesignSoftware Design

6

Transmission of Test TonesTransmission of Test Tones

1 kHz250 ms

1 kHz250 ms

Silence250 ms

Silence250 ms

• 100% modulation, stereo on, other sub-carriers and processing off

• Enable/Disable HD

• Interrupts programming, so time of tests 1:30 - 6:00 am

7

Cost AnalysisCost Analysis

Item Planned Final Our

Rohde & Schwarz FSH3 Spectrum Analyzer

8,200 8,200 -

Consumer HD Radio 150 99 - Laptop 800 800 - NI LabVIEW Professional 4,299 4,299 - BR-355 GPS 43 43 - Labor ($35/hr per person) 8,400 10,500 - USB to PS/2 adapter 10 30 10 Amplifier 4-way Splitter 20 20 20 Misc. components 320 385 185 Audio Card - 90 90 Car maintenance 60 60 60 Gas/200 miles 40 40 40 NI Sound and Vibration - 3,999 - RF BPF - 250 - Magnet Mount and Antenna 77 77 77

Total (in USD) 22,429 28,892 482

8

Changes since PDRChanges since PDR

PDR Now

Matlab gnuplot

Rapid switching on/off of HD Separate runs

3 radios 2 radios

Sony radio as reference Sony DSP not good for reference

Drive whole metro area Drive northern third of area

Simultaneous SNR of radios Alternate SNR capture of radios

DIO for HD on/off detection Button in LabView for HD on/off

9

RF Power vs. Distance From TransmitterRF Power vs. Distance From Transmitter

10

RF Power MapRF Power Map

(dB

m)

11

SNR MapSNR Map

12

Driving PathDriving Path

Full path Validation Path

13

DemonstrationDemonstration

• Show working automated system (test drive)

• Describe functionality of sub systems• Provide data plots and distribution information

14

Remaining WorkRemaining Work

• Post-processing software to create maps

• Implementation of NI Sound and Vibration Toolkit for SNR and ITU-468 Filter

• Calibrate and Validate SNR

• Drive Path

• Compare with and without HD

• Plot final data

• Prepare documentation and post everything on site

15

Future WorkFuture Work

• Full coverage drive

• Calibrated antenna to determine field strength from dBm measurements

• Use truly representative radios

• Analyze time and environmental variances of signal

16

Questions?