chicago fire digital project
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Chicago Fire Digital Project. Commander Leonard Edling Chicago Fire Department. Chicago Fire Department. Portable Radio Audio Intelligibility in Noise Testing June 23 - 25, 2009. Test Overview. - PowerPoint PPT PresentationTRANSCRIPT
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MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Chicago Fire Digital Project
Commander Leonard EdlingChicago Fire Department
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MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Chicago Fire DepartmentPortable Radio Audio Intelligibility in Noise
TestingJune 23 - 25, 2009
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MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Test Overview• Test the radio “Transmitted Speech
Intelligibility” while operating in typical fire ground background noise conditions
• Instructions given to test scorers:– Test messages would be a series of fire ground related radio
transmissions. Most transmissions will have noise in the background.score the perceived speech intelligibility of the received transmission.
– Test were not meant to try and score the “delivered audio quality” of the transmission. Rather, the goal is to measure the transmitted speech intelligibility in various operating environments.
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MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Test Overview (cont.)Score: Subjective Scoring Definition:
4
5 100% clear and intelligible speech (100% understood what was being said even though noise was present)
Less than 100% but greater than 50% intelligibility
No Received Message
0% intelligibility (speech is present but not intelligible at all)
Less than 50% but greater than 0% intelligibility
50% intelligibility (I could understand about half of the received message)
0
1
2
3
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MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Best Practices• Using the “IAFC Best Practices”, transmit
audio quality and intelligibility can be improved significantly
• Keys for improvement– The position and angle of the radio microphone
• Holding the radio microphone 1-2 inches directly in front of the SCBA Voice Port (IAFC Best Practice, Section 1, Recommendation 2)
– The volume level and clarity of voice • Speaking in a loud (not shouting), clear voice produces
the best transmit audio quality and intelligibility (IAFC Best Practice, Section 1, Recommendation 3)
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MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Radio Microphone Positioning
STANDARD POSITION• 3”-5” from Voice Port• Hand blocking port• Facing noise source
“BEST PRACTICES” POSITION • Against Voice Port or near
mouth area• Facing away from noise
source
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MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Radio Microphone Positioning
STANDARD POSITION(3”-5” from Voice Port,
Hand blocking port)“BEST PRACTICES” POSITION(against Voice Portor near mouth area)
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MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Other lessons Learned• Radios should be optimized for use• Accessories Can have a big impact on performance• Noise Suppression software can have significant
impact• Multiple settings may be needed for different types
of users• PASS Alarm Protocol Identified
– 3 Step Protocol1.Turn off PASS device before radio communications2.Cover PASS device with other hand3.Talk between PASS device chirps
• Training needs to be completed for all radio users
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MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Audio Test Recording Samples
Analog:
Digital:
Analog:
K950 Saw Cutting SCBA Low Air + PASS
Digital:
StandardBest
Practices StandardBest
Practices
Noise Shield
2
CurrentCFD
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MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
QUESTIONS?
Commander Leonard Edling
312-745-1045