Unlicensed Dremel
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Got a used 35P.
But it came with only 2 skyscreens instead of three.
So I put one in the front of the 2 foot pole and 1 in the rear, and used the two cables in the "Start" and "Stop" jacks, but of course none in the Mid-point jack.
So, question is, can you, or can you not use this chrony with just two of the 3 skyscreens?
I thought you could - I thought that it would recognize that there was no middle cable plugged in and just "do the math" from the front to the rear one. Might not be as accurate as with three, but it would work, I thought.
Well, I'm getting readings of 455 to 474 with my arrows. This is a heavy-ish 485 gr arrow from a 60 lb compound bow - so it should be about 200 fps less than those readouts - maybe 250 to 275 fps. (Is it possible these are in some format other than feet per second? Deca-meters per minute?
)
So what gives? What can I garner from those readouts? Is there some math I can apply to those to arrive at a correct figure, or MUST I buy a third (middle) skyscreen to use chrony this at all?
Clearly it's working and taking consistent readings. They're just way off from accurate. So some math simply needs to be applied, it would seem. Just divide by two, perhaps? But that seems too low - I think these arrows are going faster than 227 to 237 but maybe not.
And I'm in bright sunlight so that's not the issue.
Thanks very much. I read the instructions but they don't address whether you can just skip having a middle screen. It sort of implies that you must have it, but not absolutely clear on that issue.
The instructions also talk about "Switches" and settings for them. I don't know what it's talking about - there are no switches of any kind on the unit. All there is, is (a) three buttons, and (b) three input jacks, (c) battery compartment, and (d) printer cable output jack. That's it.
EDIT: Note that the instructions describe the velocity measured from the first to the last screen as the "primary velocity" and the velocities measured from the 1st to the middle, and the middle to the last, as the "proof velocities, which are then measured against one another to tell you whether the primary velocity is suspect or not. But even if it cannot measure a proof velocity, can't it just measure the primary, is what I'm asking. These primaries though are obviously way too high. I mean, it appears to be actually measuring the primary velocities, but not accurately. That would make sense if one or two were that high perhaps, but not all of them.
http://stevespages.com/pdf/oehler_model_35p_proof_chronograph.pdf
SECOND EDIT: Ok, now I see that the switches are inside the battery compartment. So what switch do I throw to make this work - make it disregard the middle/proof screen? Or is that possible? I adjusted the screens to make them exactly 2 feet apart, and I'm consistently getting around 467 average readings, with only 8-10 SD. Makes no sense to me.
THIRD EDIT: Nevermind; once I found the switches, all became right with the world. It was set for 3 feet between skyscreens instead of 2 feet. So, the answer is yes, it works with just two like I thought. Thanks all.
But it came with only 2 skyscreens instead of three.
So I put one in the front of the 2 foot pole and 1 in the rear, and used the two cables in the "Start" and "Stop" jacks, but of course none in the Mid-point jack.
So, question is, can you, or can you not use this chrony with just two of the 3 skyscreens?
I thought you could - I thought that it would recognize that there was no middle cable plugged in and just "do the math" from the front to the rear one. Might not be as accurate as with three, but it would work, I thought.
Well, I'm getting readings of 455 to 474 with my arrows. This is a heavy-ish 485 gr arrow from a 60 lb compound bow - so it should be about 200 fps less than those readouts - maybe 250 to 275 fps. (Is it possible these are in some format other than feet per second? Deca-meters per minute?
)So what gives? What can I garner from those readouts? Is there some math I can apply to those to arrive at a correct figure, or MUST I buy a third (middle) skyscreen to use chrony this at all?
Clearly it's working and taking consistent readings. They're just way off from accurate. So some math simply needs to be applied, it would seem. Just divide by two, perhaps? But that seems too low - I think these arrows are going faster than 227 to 237 but maybe not.
And I'm in bright sunlight so that's not the issue.
Thanks very much. I read the instructions but they don't address whether you can just skip having a middle screen. It sort of implies that you must have it, but not absolutely clear on that issue.
The instructions also talk about "Switches" and settings for them. I don't know what it's talking about - there are no switches of any kind on the unit. All there is, is (a) three buttons, and (b) three input jacks, (c) battery compartment, and (d) printer cable output jack. That's it.
EDIT: Note that the instructions describe the velocity measured from the first to the last screen as the "primary velocity" and the velocities measured from the 1st to the middle, and the middle to the last, as the "proof velocities, which are then measured against one another to tell you whether the primary velocity is suspect or not. But even if it cannot measure a proof velocity, can't it just measure the primary, is what I'm asking. These primaries though are obviously way too high. I mean, it appears to be actually measuring the primary velocities, but not accurately. That would make sense if one or two were that high perhaps, but not all of them.
http://stevespages.com/pdf/oehler_model_35p_proof_chronograph.pdf
SECOND EDIT: Ok, now I see that the switches are inside the battery compartment. So what switch do I throw to make this work - make it disregard the middle/proof screen? Or is that possible? I adjusted the screens to make them exactly 2 feet apart, and I'm consistently getting around 467 average readings, with only 8-10 SD. Makes no sense to me.
THIRD EDIT: Nevermind; once I found the switches, all became right with the world. It was set for 3 feet between skyscreens instead of 2 feet. So, the answer is yes, it works with just two like I thought. Thanks all.
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