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Old 02-17-11 | 03:08 PM
  #14946  
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waterrockets
Making a kilometer blurry
 
Joined: May 2006
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From: Austin (near TX)

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Originally Posted by mike868y
Got it, thanks. As far as actual calibration goes, can it drift over the lifetime of the device? Like is 250w on my pt now not what 250w was on my pt last season?
I've seen one PT change calibration, but that was on its way out (in need of a rebuild). Mine hasn't changed at all since I've had it. For the sake of consistency, I test with steady temperatures, and only if the wheel has been in the same environment for more than an hour, with no sunlight. I don't want thermal expansion affecting the test.

FWIW, I've found that it helps to do four tests and average the results. This gives me consistent results year over year (within 0.1%)
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