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Just wondering, can you doppler a turbine?

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Old 09-16-2008, 03:50 PM
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LGM Graphix
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Default Just wondering, can you doppler a turbine?

Wondering how fast this pass was on my Kingcat at the Princeton rally this weekend. I know the jet has been on radar at 235mph but I think this pass was faster, not sure. Can turbines be doppler'd? The pass is at 5:44 on the video.
http://www.youtube.com/watch?v=p_WvBO4tmEc&feature=user

Jeremy
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Old 09-16-2008, 04:27 PM
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Default RE: Just wondering, can you doppler a turbine?

You can dopler a turbine, but the music in this video is blaring making any dopler impossible it showed up as a bunch of noise on the spectrometer.
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Old 09-16-2008, 04:47 PM
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Default RE: Just wondering, can you doppler a turbine?

I have never been able to Dobbler a turbine but I have trouble with 4 strokes too.
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Old 09-16-2008, 06:02 PM
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Default RE: Just wondering, can you doppler a turbine?

I thought the music might make it tough, oh well, just thought I'd ask thanks anyway guys
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Old 09-25-2008, 02:17 AM
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Default RE: Just wondering, can you doppler a turbine?

Can someone explain where/how you doppler off a video?

Thanks.
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Old 09-25-2008, 08:55 AM
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Mike Connor
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Default RE: Just wondering, can you doppler a turbine?


ORIGINAL: nesikachad

Can someone explain where/how you doppler off a video?

Thanks.
I use Windows sound recorder to record a 2-4 second wav file from the video.
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Old 09-25-2008, 09:13 AM
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Default RE: Just wondering, can you doppler a turbine?

Mike,

Thanks but now I feel even dumber.

Exactly how does this work? I have no idea and middle school science class isn't booting up in my hard drive all that well.

If you could educate a dummy I'd be appreciative!
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Old 09-25-2008, 09:40 AM
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Default RE: Just wondering, can you doppler a turbine?

Open up your compatible video file in Sony SoundForge,

Resample the whole file to 44kHz

get the part you want to doppler, copy and paste it into a new file with 44kHz sampling,

resample the new part to 11kHz for the doppler software (the less samples, the easier to identify the doppler shift)

save it as .wav format, open it up in doppler software

and voila.. very accurate readings..
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Old 09-25-2008, 10:16 AM
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Default RE: Just wondering, can you doppler a turbine?


ORIGINAL: nesikachad

Mike,

Exactly how does this work?
If you don't have the knowledge and software like liquid_TR you can do this.
The Windows sound recorder is under accessories, entertainment.
Place the microphone by your speaker.
While the video is playing you can record a short wav file starting it just before the aircraft reaches the camera during a close in level pass.
The recording should include the flight just before reaching the camera through just after passing the camera. Usually 2-4 seconds.
you can get the Doppler software at http://www.sprut.de/electronic/soft/scope.htm . (Goggle can translate to English)
There are several threads in this forum with info on this software.
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