Two observations:

1. The last 2 days cvs have crashed when I move the ILS freq. to nav 1 for SFO 28R. This does not happen every time.

[EMAIL PROTECTED]:/usr/local/FlightGear> ./bin/fgfs --disable-specular-highlightInitializing OpenAL sound manager
Oops AL error in sample set_volume()! 1.15 for /usr/local/FlightGear/Sounds/wasp.wav
Oops AL error in sample set_volume()! 1.3 for /usr/local/FlightGear/Sounds/coughing.wav
Fatal error: Failed to gen buffer.
(received from )
[EMAIL PROTECTED]:/usr/local/FlightGear>


2. The tower view doppler shift seems to be in the wrong direction. The frequency shift must be up when the ac is inbound and
transitions to a lower frequency as the ac passes the observer. This is because the inbound ac velocity is in the same
direction as the wave front velocity which means shorter wave length. As the ac receeds, the
wave front you hear is moving in the oposite direction as the ac, wheich means longer wave length
and lower pitch. I think the vlelocity that matters is the component of the ac velocity toward the observer.


I just drew a vector diagram to get the wave length observed, and then F observed should be the reciprical. Don't have a physics book handy, but this seem right:

F_observed = (C/(C - cos(t)*V))*F

where F is the stationary frequency, C is the speed of sound, t is the angle between the ac velocity vector
and the line to the observer from the ac, and V is the magnitude of the ac velocity.


Does anyone have a better derivation?

Not complaining, just trying to help.

Dave Perry




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