can the transponders be wrong

[bmfgsxr]

Correct. But that's not what we're talking about currently. You made the incorrect statement that it doesn't matter at what point on the track you time a lap, it'll be the same as timing it from somewhere else. That's rather stupid.

Set up two transponders, one (transponder A) at start/finish, one in T8 (transponder B).

Make a mistake in T10 on lap 4, run off the edge of the track losing some time,  then continue to start/finish.

The lap that was run at full speed from T8 to T8 without error (recorded by transponder B, part of laps 3 and 4 relative to start/finish (race scoring))  will be X.

The lap run from start/finish to start/finish (recorded by transponder A, lap 4) will be SLOWER because you screwed up T10 before completing the lap RELATIVE TO START/FINISH.
 
The reverse will then also be true on the next recordings (provided another rider error isn't made). Transponder B will record a slower lap (T8 to T8, with a screwup in T10) and transponder A will get a full-speed lap (start-finish to start-finish with no errors)

How hard is that to grasp? Everything is relative to the observer's (timer's) location.

- Roach

boy oh boy has this become something. sure, potentially you could run different lap times with two beacons set up. but regardless of anything, if you are timing 8 laps of a race from one point your lap times should just about mimic the times the transponders will record on the front straight. if your only going to time one lap from turn 8, and compare it to one lap run from start/finish to start finish there is a possibility that the times could be different. but that is not the original question i asked. 8)

[THE_D.O.C.]

i'm still curious why roach needs two transponders for a precise lap? one suffices everywhere but in roachville. who cares if you boffed turn ten? why on earth should it matter? why the whole talk is off topic for this thread. the fact is, transponders don't lie. racers do.

[bweber]

Why even use a transponder or stopwatch if you just want your AVERAGE lap time.  If that is the case, take the amount of time that elapses between the green flag dropping and the the time you pass the checkered flag waving and divide it by the number of laps you ran.  That is your average lap time, but who looks at average lap times? What good is the average lap time?  
I just wanted to point out how a stopwatch (with a good operator) and a transponder could disagree on something like best lap time during a race.  Someone may come in and look at the time sheet one of their pit crew made, or even check an on board lap timer and see they ran a best lap of 1:14:39 at Blackhawk during race.  Then they may get the official print out showing the transponder times and be disappointed when the transponder records their best lap at 1:14:8.  
It has been explained and it is a simple concept.

[r6_philly]

Dafan, you're right, but that's not what I meant. You are correct, but your example isn't timing the same lap. You're comparing lap charts, not laps. We do lap timings from different locations on the circuit all the time, all you need to do to get the lap charts back in synch is to net out the differences between the untimed portions. Rework your example and you'll see what I mean, the difference in lap times in your lap chart can be brought back to perfect alignment with some simple adjustment. That was my original point, i.e., that lap times for the same lap from accurate timings will be identical regardless of where they are taken.

First of all, I am not splitting hair :D

I wasn't talking about lap charts from different location of the track. I merely broke down the track into 3 sections to illustrate why 2 readings can occur.

Simply consider this: a vehicle is accelerating along a track at a CONSTANT rate of acceleration. If you measure between any 2 points of equal distance, lets say 1/4 mile, you will yield different results because the difference in average velocity based on the point in time of the run. So if you consider that over a variable acceleration (such as a human racer) it would dictate that an constant average of volocity will not be able to be achieved. So based on the variance of the average velocity, you will yield a different lap time reading, even though you are timing the same distance lap after lap, from 2 different points. 2 seconds a lap would be a lot to achieve as a different, but there will be difference.

Of course the over all elapsed time would be the same in both cases, but distance is only one factor here, and the same distance would not yield The same time.

Ok I am pretty convinced of my view here, please help me figure out that I am wrong if I am. Or I think I over paid for that engineering stuff :D

[G 97]

If my buddy is timing me in T8 at Summit and the beacon for the transponder is past start/finish, what happens if I let off the throttle after I go by my buddy? Or crash in T9? Or how about I pull into the pits?

Unless the person with the stopwatch and the transponder beacon are in the same location, you are looking at two different laps (that happen to have an overlapping section). One starts and finishes at the beacon, one starts and finishes at the stopwatch location. Unless you are so consistant that your speed/time doesn't ever vary in any given section of track at any time, the two won't agree.

- Roach

A lap is nothing more than a circle.  It does not matter where you start or finish.  As long as you complete the circle.  The only lap times that would vary greatly are when starting and ending.  Other than that it does not matter where the transponder is positioned or the stop watch.  The lap times will be extremely close.  You can time from anywhere, it does not matter.  A lap is a lap.  Rather simple.  
Time from T-1 or T-8,  Your times will be the same.

[Nate R]

But if you have 2 diff locations, the same lap is impossible. You will have to complete more than a lap to make both see a lap, and thus the time could vary greatly.

Let's say transponder A and B are both on the front straight of a track.

You pass transponder A after completing a lap around from that point. Then stop, and then roll past transponder B which is 1000' later. Transponder B will have a MUCH longer lap time than transponder A. Both are recording one lap from the point of the respective transponders. Think about it, you can have differences.

Now, where do you want to do this experiment? Will my $1000 be in cash, check, or Cashier's check?  ;)

[G 97]

But if you have 2 diff locations, the same lap is impossible. You will have to complete more than a lap to make both see a lap, and thus the time could vary greatly.

Let's say transponder A and B are both on the front straight of a track.

You pass transponder A after completing a lap around from that point. Then stop, and then roll past transponder B which is 1000' later. Transponder B will have a MUCH longer lap time than transponder A. Both are recording one lap from the point of the respective transponders. Think about it, you can have differences.

Now, where do you want to do this experiment? Will my $1000 be in cash, check, or Cashier's check?  ;)

Yeah, I understand that.  If you intentionally go out and stop or slow after hitting a transponder etc.   ::)
Everyone know the first lap is crap anyway. ;)

The point is, a lap is still a lap.  Over the course of multiple laps it does not matter from where the location the lap was timed from.  

[TZDeSioux]

This argument is gay and annoying.

[bweber]

This argument is gay and annoying.

SuperDuck, I know the stuff you post is of the highest importance, like eating cheetos, who's going to BHF and how many times you've crashed this year.  I checked your post history.  It is really important and insightful stuff.
Nice comment.

[MudDawg]

Yeah, I understand that.  If you intentionally go out and stop or slow after hitting a transponder etc.   ::)
Everyone know the first lap is crap anyway. ;)

The point is, a lap is still a lap.  Over the course of multiple laps it does not matter from where the location the lap was timed from.  

So with that in mind EVERY lap you run is exactly identical?  man...you must be good.  Dunno about you but I fluctuate in laptimes....some are good laps some are bad.  Sometimes it's traffic, sometimes I overcook braking into a turn.  I guess you don't......ever.

And Duck is right.  This is annoying.

[TZDeSioux]

SuperDuck, I know the stuff you post is of the highest importance, like eating cheetos, who's going to BHF and how many times you've crashed this year.  I checked your post history.  It is really important and insightful stuff.
Nice comment.

I try not to be insightful but the point was that the same thing is being said over and over and over and over with a few hypothetical situations thrown in here and there and then the same point over and over and over again.  

[THE_D.O.C.]

geeee... i say this thread is silly, and i'm a spoop. mr. duck is right.

i gotta do it again.

"hey, could you go stand in turn five and time me? my lap times are faster from there."

HA HA HA HA HA HA HA HA HA HA HA HA!!!!!!!!