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Radar check of target speed from the 27 - OK?

Discussion in 'Uncategorized Threads' started by Neil Winston, Dec 16, 2007.

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  1. Neil Winston

    Neil Winston Well-Known Member

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    I posted the rules for setting targets by speed on another thread. Here's what I wrote:

    Here's a section from the September 2007 rulebook, the one that will cover the 2008 target year. It covers the difference between radar guns, in part at least.

    (start of rule)

    "F. Rules for the use of Radar Guns and Chronographs to set Target Speed

    There are two types of radar guns, high-power and low-power. The practical difference between them is that high power guns work reliably from the 16-yard line and low power guns don’t.

    High power guns (Decatur, Stalker, most “police radar guns” and similar) are to be used at the 16-yard line. The trap oscillation is stopped, and the target measured is a straightaway. The gun is pointed horizontally. The correct speed for a singles or handicap target is 42 MPH with a tolerance of plus or minus 0.5 MPH. The correct speed for the right target of a doubles pair is 39 MPH with a tolerance of plus or minus 0.5 MPH.

    Low power guns (SportRadar, Bushnell, and similar) are to be used at the back of the traphouse and at the level of the top of the traphouse. (Holding the gun higher than that will lead to a target which is too fast.) The trap oscillation is stopped, and the target measured is a straightaway. The gun is pointed horizontally. The correct speed for a singles or handicap target is 42 MPH with a tolerance of plus or minus 0.5 MPH. The correct speed for the right target of a doubles pair is 39 MPH with a tolerance of plus or minus 0.5 MPH.

    When a radar gun is used from inside the house, the correct speed for a singles or handicap target is 44 MPH with a tolerance of plus or minus 0.5 MPH. The correct speed for the right target of a doubles pair is 41 MPH with a tolerance of plus or minus 0.5 MPH.

    A chronograph is to be used as close to the trap as practical and tipped up at approximately the same angle as the flight of the target. The correct speed for a singles or handicap target is 67 ft/sec. To set doubles with a chronograph, set a singles target to 76 ft/sec. and then switch the trap to throw doubles without changing the spring tension.

    Note: target speed may be set by distance as above or by speed as determined by a radar gun or chronograph. Target must be set by measured speed or distance but not both."

    (end of rule)

    So far, so good. With a high-power gun, set targets from the 16.

    But it's as the day progresses that these guns really start to show their stuff. A setter can walk down the line behind the shooters and, by checking them all from a particular trap until he gets a real straightaway or two, see if anything has changed.

    Or can he? A shooter is certainly justified in wondering if, when you move back from the 16 to the 27, the readings stay the same. And are the results from the 27 as "good?"

    Since I do a lot of that back-fence checking myself, I'd determined to my own satisfaction that if there were any differences they didn't amount to much. But I'd never done a serious test, which is to say, I'd never written anything down.

    Yesterday, Minneapolis Gun Club President Jim W and I went to trap 5 to find out. Jim set the trap to 20 degrees with an angle meter, backed off a few turns from the day's Jackpot settings, and using a Decatur gun on a tripod, we clocked five targets from the 16. We then took the tripod to the 27 and measured five more.

    Jim added three turns of spring tension and we repeated the test, discarding the first target after the change. And so it went, ending when we had tested four spring tensions from each of the distances, 16 and 27 yards.

    Are the speeds the same?

    [​IMG]

    Yes, the speeds are the same. The total average difference, 0.25 MPH is similar to typical differences between two consecutive targets. And it's only one-quarter of the spread in speeds permitted by the above rule. As a practical matter, it's nothing.

    And are they equally variable? That is, do the 27-yard readings "jump around more" as a result of the weaker radar return signal is seems like the gun must be getting from farther back?

    Five targets four times is not enough to answer this question, and variability is a sticky problem anyway. With that warning, let's look at this admittedly inadequate test of variability.

    [​IMG]

    At least there's nothing here to say there's any difference between the ability of the Decatur gun to measure speed at these two distances.

    These data support the claim that a setter has justification in checking the speed of targets from the 27, even though they were originally set by speed from the 16.

    Neil
     
  2. quicky

    quicky Member

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    Thanks Neil!

    Now, what is the schedule for the interesting info. on high-altitude patterning? We are waiting with bated breath! Quicky
     
  3. Bob Hawkes

    Bob Hawkes Well-Known Member

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    Neil, I/we use a Decatur for setting targets also. I have found a slightly greater difference than what you are showing. BUT, I did not use a tripod as you did. I don't know if that would make a difference. I did not write any notes down, so I don't have any records of exactly what we had for readings. One thing I have done, is check consistancy between our Star's, Pat's, and WW handset. It was interesting to see which spring stayed the same even with temperature changes day to day. I also found the thoughts interesting about the "old" WW handsets perhaps averaging a wider target spread.

    Question? Do you recommend using a tripod for checking speed, or is a "steady" hand/posture sufficient? I always enjoy your thoughts and comments on this site. Thank you for your input and all of your work for us. Bob Hawkes, MMSC
     
  4. Neil Winston

    Neil Winston Well-Known Member

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    Bob, unfortunately I have to recommend strongly _against_ using a tripod with the Decatur gun. It's convenient and in this case, there wasn't much to do so it was "safe," but even with the little steel bushing provided with the gun the case is not nearly strong enough to withstand tripod mounting on a regular basis. The case will break, and sooner rather than later in my experience*. Just hold it; it works fine that way.

    I think writing it down is the only way to fully explore this kind of situation. In this case, Jim pulled the targets and read the readings to me while I wrote them down. Maybe he will comment here on his - or anyone's - ability to determine what was going on as he did the test, without a written record to go back to.

    Quicky - half the data is on a hard disk in a dead WinBook laptop but Ron Baker has suggested how to get at it; the rest is on thirty rolled sheets of pattern paper under my dining-room table, secure but unanalyzed. I'll have to ask you to keep bating your breath.

    Neil

    * Like this:

    [​IMG]

    And this is not just a cosmetic problem. As you know, Bob, all the numbers the unit will ever need are sealed up within the case at the time of manufacture - it's just the job of the microprocessor to find the right ones to put up in the readout when they are needed. But the design depends on the impermeability of the case. With damage like this the numbers can run out through the hole and begin to pile up invisibly around your feet and lead to a nasty fall if you aren't careful.
     
  5. Paladin

    Paladin Well-Known Member

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    My findings parallel yours Neil. I've not noticed a perceivable difference with random speed checks. I believe the Decatur's are a very powerful radar gun. We have even used two Decatur's, alternating the readings, and all was ok. I've taken many readings at 35 yards back and not noticed a difference. Again, unscientifically done. One certainly does have to wait for a true strait-away target or three, to be accurate about it if a squad is shooting.
     
  6. Ithaca$$$Grade

    Ithaca$$$Grade Active Member

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    Yesterday was about as perfect weather conditions that we have in MN this time of year. There was absolutely no wind to speak of when we were throwing targets, 3:45 in the afternoon, bright, sunny day.

    I was surprised how consistent the readings where, in both straight aways and on the angles. We threw some targets on auto also to see how much the readings varied from straight aways. A full left target 38 mph, full right, 38 mph, right on the mark.

    For those interested, we were throwing the targets off of a Pat trap, with a rubber band "spring", 3 different tension settings, with a heat lamp in the bunker and a magnetic heater on the oil reservoir. The trap had been used all day and we threw a few "see one" targets before Neil started recording the speeds.

    I know that shooters in our area are a lot more "comfortable" with the target settings when the club's they are shooting at use a radar gun to set the targets. More so concerned about the gun than the height pole. At the Minneapolis Gun Club we'll gladly reset the height of the targets if someone has a concern but once they're set with the Speed Pro gun and the speed is right, that's what we shoot. And, after going through the testing with Neil, I'll feel more comfortable checking the targets either up close or further back.

    Thanks Neil for taking the time to run the tests.

    Jim W
     
  7. washandwear

    washandwear Member

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    Just so you know. Jim and Neil didn't state the outdoor temperature when these radar readings were taken - this is real dedication to the sport - Brrrrrr!!!!!

    I shot Saturday morning early and it was -4F when we started around 8:30am.
     
  8. Paladin

    Paladin Well-Known Member

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    Neil, you mentioned that Jim used an angle meter reading of 20 degrees to set the trap angle. Is the angle meter usage something that is on the radar screen with you or the ATA? Suggested guidelines maybe, just as there were for pre-rulebook radar/chronograph usage?
     
  9. Southern Gent

    Southern Gent TS Member

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    Just curious but how does .25 MPH get to be one-quarter .5 MPH.

    Even if you take the range of tolerance, you have .5 MPH vs. 1.0 MPH.
     
  10. Neil Winston

    Neil Winston Well-Known Member

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    Paladin, several people I know to be serious and realistic have good luck with angle meters. I have several, two of the electronic type, and I can't set two traps alike with them. Three is totally impossible if you are trying to set them at Metro Gun Club in Blaine, Minnesota, and I have witnesses.

    They are not on _my_ radar screen, I'll tell you that, but just as the ATA has encouraged clubs for years to use radar and chronographs even in the absence of rules, clubs can use angle meters if they want, and maybe something will come of it. It took eight years for radar and chronographs so don't look for results tomorrow.

    Neil
     
  11. Neil Winston

    Neil Winston Well-Known Member

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    no longer needed.
     
  12. Southern Gent

    Southern Gent TS Member

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    "Zero point two five is one quarter of one."

    Thanks, I misread the datum.
     
  13. Paladin

    Paladin Well-Known Member

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    Neil, we initially had doubts about the angle finder,,until it was discovered the pedestals that the height pole rested on were not at a consistent height, after being transit set two years previous. Maybe due to freezing and thawing ground. Unless a pedestal is known to be correct, I don't trust them. The digital level has worked very well for us. This is with Pat's only though.
     
  14. washandwear

    washandwear Member

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    Paladin

    Do you have a preference/recommend an angle meter that works for you?

    Happy Holidays
     
  15. Paladin

    Paladin Well-Known Member

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    I'll paste the excellent suggestions from Bob Schultz;


    "IF your Pat Trap is located in the house properly. Meaning that when the target on the arm is at rest, with the machine cocked, it is at the same level as the top of the pad on post three...then a target launched at 21.2 to 21.5 degrees will be very close to 9.5 feet high at the 10 yard distance. Each full degree on the angle finder represents 6.2 inches of elevation change and each tenth of a degree ( measured with the Digital Angle finder) is 5/8 or .62 inches. This seems close enough for me.

    Knowing this, if you are setting targets on a bad day with windy conditions you can set the targets to the standard setting THEN make minor corrections to adjust for the prevailing conditions. However, you would be amazed at how little of an adjustment is necessary from your standard target to obtain shootable targets.

    The point being, on a good day you can set very consistent targets field to field and shooters will be happy. On a bad day you can adjust from a known standard on each field and throw very consistent targets and shooters will be happy. Last time I checked we do this for fun. Most shooters like to shoot good targets and good scores. If you want to have shooters return to your club, make an effort to set the best targets you can. They will appreciate the effort and come back for more."
     
  16. Paladin

    Paladin Well-Known Member

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    Maybe I misunderstood your question. As far as which angle finder to use, get a Sears 10" digital level. It slides just perfectly between the throwing plate and the plate that the targets sit on. About a year ago, they ran $29.99 to $39.99 depending on if they were on sale.
     
  17. Neil Winston

    Neil Winston Well-Known Member

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    Up just this once.
     
  18. JBrooks

    JBrooks TS Member

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    I can assure you that if you set targets this way they will be either too low or too high. At least according to every squad.
     
  19. BAP

    BAP TS Member

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    I have checked and rechecked my setting poles until I was sure they were correct. I have been setting the targets to the pole and then listing the angle of the machine on the wall of the house. All the settings are between 19 and 21 degrees with the settings of each individual house varying slightly on different days which I attribute to wind and changes in humidty. There may be some variation due to the use of a sports radar gun which only measures the speed in whole numbers. Over all I am pleased with the results and feel that I can come close with a digital angle meter on my fields but that is by using the results of each house individually and not adding them. Whats your take on this Neal? Bill Parson Jr.
     
  20. Bob Hawkes

    Bob Hawkes Well-Known Member

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    Bill, You've got to bite the bullet and spend the $600+/- for the better gun. I used the same one as you for a couple of years. If you go to the better one you will be surprised how much the ability to read in tenth's of a MPH means. You are able to set a much more consistent target field to field. BTW, We find it just as quick and more accurate to use the pole on top of the stake. I prefer the pole with the radar gun and intend to remove our 50 yard stakes. That should conform with the new writing in the rule book. Shoot well and often, Bob H.
     
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