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Measuring Trap Target Speeds

Discussion in 'Uncategorized Threads' started by argus tuft, Jun 5, 2007.

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  1. argus tuft

    argus tuft Member

    Joined:
    Jun 3, 2007
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    Location:
    Queensland, Australia
    Can anyone tell me the correct speed for a Standard down the line trap target as measured with a Radar Gun and at what point of flight it should be measured


    Argus
     
  2. Neil Winston

    Neil Winston Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    7,848
    Angus, you really can't do what you suggest - that is, measure the speed at some arbitrary point in its flight. Just using a gun as described hereafter, lock the trap and go for 42-43 MPH on a straightaway, the lower figure for yellow Decatur Guns, the higher for Sport-radars and Stalkers. But that's really cutting way finer than necessary. Just get it in that range and everything will be A-OK.

    Radar guns simply measure where they do, and that's a bit after the target gets above the roof of the house.

    There are certainly those who point it up and so on in the belief that they have lessened the cosine error by measuring the speed when the angle between the gun and the bird is less. But then that would sort of be canceled out by the fact that the speed would be measured farther out on the flight-path, and so slowed by some amount. In practice, it all "averages out."

    Luckily, it's mostly theory. The radar beam is not a pencil, it's a cone.* If you do it with a lower power gun and so have to be at the rear of the house, then there's really no difference - up orf lat, the readings are the same. If you are at the 16-yard line, the cone coverage just means that you are kidding yourself; the gun sees the target at about the same time no matter if you point it straight or up.

    So just point it out. That's what we are going to do at the Grand.

    Inside the house is _not_ more consistent and gives a speed which is about 2 MPH too high.

    On the roof of the house with a Decatur gun is _not_ more consistent, and is still about 1.5 MPH too high but I don't know why.

    In short, there is way more going on in these radar measurements than pointing the gun and a lot of it doesn't make any sense. The only way we are all going to get the same results is to do it the same way, and that's at the roof of the house looking straight out for low power, at the 16-yard line, looking straight out for more powerful guns. Go for 42/43 MPH for singles and handicap. Thirty-nine plus, maybe 40 for the right bird in doubles.

    Neil

    * and what's worse, a ragged-edged cone. What happens is that as you move more and more out toward the edge of the cone, sensitivity decreases; there's not sharp line. So it's a fuzzy edge, and best left out entirely, that means, use the center all the time; point it straight out.
     
  3. Jim101

    Jim101 Active Member

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    Jan 29, 1998
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    Location:
    Knob Noster, Mo
    I use one of the lower powered guns. I just set it up looking straight out over the roof. 42-43 mph seems about right.


    <a href="http://photobucket.com" target="_blank">[​IMG]</a>



    Jim
     
  4. Old Cowboy

    Old Cowboy Active Member

    Joined:
    Jan 29, 1998
    Messages:
    2,988
    My Radar gun is the same model as Jim's. IME, a target that shows 42-43 mph with the radar held level at the back edge of the roof will show 44-45 mph with the radar inside the house on a "Pat-Pal" measured right off the plate. From my limited experimentation and assuming both are done properly I don't think one way is >either< more or less consistent than the other. I'm curious Neil, why would you describe the reading taken from inside the house as "2 MPH too high"? It's actually going the same speed, just measured in a different manner-------

    John C. Saubak
     
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