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Old 04-21-2011, 03:18 PM   #13
Bret Kepner
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Location: Saint Louis, Missouri, USA
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Default Re: Red Light Answer

Having conducted my own Drag Racing School for fifteen years, it astonishes me how many veteran drag racers still don't understand anything about the starting line electronics array.

Pat's information is absolutely correct. The Stage-Loc system does not rely on a receiver since it has no function in the timing system; it merely keeps the "staged" bulb illuminated even if the front wheel has rocked back out of the actual "staged" beam. I'd venture a guess more than ninety percent of all racers have no idea the Stage-Loc system even exists let alone how it works.

In 2011, all NHRA National Event facilities have Stage-Loc and it's usually a permanent function requiring no activation. This means it is also functioning at regular events at most of these tracks.

Concerning the infamous "stationary red light", Jeff Stout's assumption is not fiction but fact. If the front wheel vacates the beam for a thousandth of a second, a red light will register. It has been proven a "flicker" of the "staged" bulb for less than two hundredths of a second will not even appear in the bulb since the filament will not have cooled before the electricity resumes its current through the filament. A flicker of three hundredths or less will not be apparent to the naked eye so nobody will see it, anyway. The vast majority of all video cameras record at a rate of one frame every 0.040 seconds, (four hundredths), so a flicker of less than that amount will not be visible on video, either.

Sun reflection is still a (rare) problem at some tracks but the effect has been reduced by variable infra-red frequencies used in the system. I still race at a few tracks with the old "headlight and photocell" arrangement and these problems are much more common with forty year-old equipment.

Hang in there, Pat. We'll keep you distracted as long as we can!
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Bret Kepner
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Last edited by Bret Kepner; 04-21-2011 at 03:20 PM.
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