At what point can I assume its a defective unit? Or is this the limitation of ST?

[calebm1001]

How bad do these readings need to be for me to believe I have a defective unit? I have a lot of footage of hitting center or clearly to the right of center and getting a bogus HLA that sends my flight path on a left launch angle. I understand the tolerance is roughly +/-2, but is that EVERY shot?! On some shots that are cleary center, I will get 6* HLA to the left. I never get anything that seems out of the ordinary to right. It's as if this unit has a left HLA bias and it has been this way since I got it.

In the images below, I am hitting to the right of center according to my FMJ. The laser line is going straight down the alignment stick and the ball is clearly hitting into my screen heading in that direction. Yet, in ST range and TGC nearly every single ball starts left. This happens on literally 90% of the shots I hit on ST - 9 out of 10 full shots are like this. When I swing easier with a low ball speed it tends to pick it up correctly.

I have been at this for four months. Made a few posts about alignment to try and get some advice. Have a large black sheet behind me etc. Skytrak is level. Is on my smaller CCE hitting mat so is at the same height etc. Nothing I do fixes this other than aligning the ST to be looking across me to the left so it's forced to read everything as going right, if that makes sense.

Is this something I should be weary of and send in for a checkup since I am still inside warranty?

EDIT: Look for the impact marks on the screen and you will see the little black outline of the ball. I realize they are hard to see in these potato images.

[Mouse Potato]

This thread is very interesting for me. I bought ST back in January and immediately noticed what I thought was a left bias in many of my shots. I took the unit to the driving range and shot shape was pretty accurate but the unit was definitely reading a little left of where the shots were actually going. I thought that this was simply an alignment issue.

the units alignment tool is awful however. You can see from the naked eye that the laser dots are pointing way left of the actual target line. If I lined the unit up using the alignment tool, the ST unit would be pointing right of target which would increase the amount of left bias on the shots.

I haven't been able to do any more testing as I had a hip operation last month meaning I can't hit any balls until early July. Should the 'string method' be used to line the unit up, or should ST be providing a unit that measures its own alignment correctly? This is not a cheap piece of electronic equipment after all.

Russ

[colinjm18]

They did remove the alignment mode in a past update because it wasn’t very accurate. Lots of people wanted to keep it so they added it back. They say the best way is to have the unit square to target line.

[Mouse Potato]

Thanks Colin, now this may be just me but I think that this is a basic requirement for a device that relies heavily on good alignment. If the unit doesn't know what is 'straight' then in my view, there is a problem.

[Gresh12]

I wonder if they could creat an alignment mode where you lie down an alignment rod over the red dot aligned with your target. The Skytrak would do its photos and either calibrate that as straight (maybe impossible to software correct on that at this stage) or like the leveling feature tell you how offline you are so you can adjust unit until it is reading square to the alignment stick.

I have never setup any of the other launch monitors myself before using them as they’ve always been at someone else’s facility but presumably GC2 would have to be aligned well also (maybe the radar units less so)?

[Gresh12]

I raised this before and it didn’t get any real traction at the time but my unit very rarely produces a HLA between -1.9 and +1.9 that isn’t just straight. The range view rounds to nearest degree so it wasn’t obvious to me unless looking at raw data but I just don’t see figures like .2, . -.7, 1.3 etc. Once it gets outside of 2 I see lots of variety.

I still think the unit is good for the price point but when I’m doing a skills assessment or playing TGC I do get some shots I’m confident weren’t that far left IRL.

[Morini]

I raised this before and it didn’t get any real traction at the time but my unit very rarely produces a HLA between -1.9 and +1.9 that isn’t just straight.

You are absolutely right. The large range of "straight" is a clue that HLA measurement is not a precise measurement. And that should be no surprise. VLA is very accurate because the ST needs only to compare the x and y movement of the ball in the two images. For HLA, you are comparing the size of ball in images. The smallest change in ball size you can easily detect is one pixel (or larger), but with image processing, sub pixel accuracy is achievable.

Thus, the confidence band shot to shot of Skytrak is low. If it reads that any one shot was 10 yards offline, it could in reality be dead straight or even more offline. HLA error is a concern for all perpendicular photometric launch monitors, GC2 included.

Now instead of looking at a single shot, we are looking at say a hundred shots, we can be more confident, assuming no bias left or right. On average, your shots will be correct yards offline. Still, a bit deceptive. That approach you stuffed to 6 feet in sim play, could in reality have been off the green. Or the opposite.

Come to think of it, if additional hardware were to be developed, I'd much rather have an overhead/behind ball cam to measure HLA more accurately, than say club data.

[calebm1001]

This is a great look into how Skytrak obtains the info from its cameras. How close is GC2 compared to ST?

I would agree with you on getting more accurate HLA over club data. However, wouldn’t ST having accurate club data give us a better idea of HLA as well? As if killing two birds with one stone?

[calebm1001]

I don't think some of the comments here really understood what to look at or didn't read the entire post. Let me try to clarify and point somethings out in hopes that other experiencing this can find some help as well...

Look at the impact on the screen (circled in black) compared to the red laser line. That laser line is set directly on top of the FMJ alignment stick (as noted in the OP). So, the way ST works, that means 12" to the LEFT of that, is where my aimpoint should be, because that is how far away the red dot shoots out past the alignment stick. I also circled that and drew a line to represent my TRUE aimpoint.

If you see the ball flight calculations, you can clearly see that the ball started left. But I hit the ball right towards the laser, about 6" from the laser.

[calebm1001]

trhuke I’m going to go ahead and ignore all of you comments moving forward. You didn’t even look at the photos posted or read what I posted. Or you did and just don’t understand. No worries, just can’t continue to explain if you’re struggling to understand what you’re seeing. I appreciate the advise but it’s just wrong.

[calebm1001]

Coz everything is aligned. The offset is where it needs to be etc. it’s all good though. I’m working with ST. Seth is callin me on Monday to talk before sending in.

[Wizard of Coz]

I understand your frustrated. If something is a miss with the unit none of us can fix it. Many times it's user errors and that's what i'm looking for as are many others. Like I posted earlier if you happen to be heading to kalamazoo bring it with I would be more than happy look at it. Im 99.9 % sure I could confirm it being jacked up or not in less than 5 minutes. You could check out my cave
too.
I used skytrak since 2016.

Oh and I agree with Morini and his way of getting it lined up but I also agree with you and wouldn't be happy doing that. My skytrak happened to be lined up with hitting parallel to my case.

[StanMI]

Just for giggles, have you turned on the "Alingment Mode" in the Skytrak to see where it says it's aimed ? I know everyone says it's not always accurate, but Just a thought. Also, have you tried it without the FMJ on ? Looks lik e that was asked once maybe ibmissed the answer.

[calebm1001]

I have. And actually, as of a couple weeks ago Alignment mode doesn’t work at all. The second dot never shows and my unit goes into a continuous reconnect loop. I have to restart everything to get back to the range.

[dg_1983]

Just a couple points from me.......the laser line - you are assuming that's parallel to the internals of the skytrak? Not only do you have plastic case of the skytrak tolerances to consider it sounds like you also have tolerances of the FMJ in your allignment. I guess my point is that you don't know how accurate that laser line is to start with. We are talking individual degrees so the smallest of errors make a difference.

The other thing to consider is your suggestion of 12inches parallel left of that laser is your ball-target line. The throw of the laser is massively impacted by your height of the skytrak unit compared to the mat. The higher the unit the further that laser throws so the further left that dot will appear

I guess all in all, I'm in the camp of getting my hitting setup parallel to what I want , hanging a string line and adjusting the unit until it shows a string hit shot as launching straight consistently.

Fwiw it's about getting the data to be reflective, not having a nice plastic box perfectly alligned. I don't not believe any other measurement is impacted because HLA is off.

[kalcormier]

This!.....

[Morini]

This again.

As stated earlier, it is better to be less scientific about alignment.There is no guarantee that the internals are lined up parallel to the case. Simple solution. Tweak unit alignment until straight shots go straight. Once this is done, your HLA should be accurate ON AVERAGE, but shot to shot some may be off due to the HLA measurement error

If ST (without FMJ) needs to be more than 3 degrees offline in order for HLA to be accurate, I would send it back. Same if HLA error shot to shot regularly exceeds tolerances.

[Morini]

I guess im just not willing to point my unit left to trick it into thinking I hit a straight shot. Hopefully their CS team can provide some assistance.

This is clearly where we diverge. You are not tricking your unit. You are actually aligning the internals with your target line.

There can be error in the internal alignment of the ST in its own plastic case. This is typically small. There can be a MUCH larger error alignment error added if the unit does not sit parallel in the FMJ case.

In an ideal world, it shouldn't be this way, but it is. There are fairly tight tolerances, and there are individual variances. It would be very hard to solve with physical pre-alignment alone. Trackman aligns itself with a camera facing down the target line, sometimes using a string (surprise surprise). Not an option for ST as there is no software alignment option. Personally, I'd use 3 degrees alignment error as cutoff for sending it back. But that is a personal choice. To each his own.

[calebm1001]

True, and maybe I’m just expecting way too much out of this unit for it’s cost. It does work when I point the unit left. It’s unfortunate the alignment mode doesn’t work and the FMJ doesn’t have better QC. We shouldn’t have to hit a dozen chips, then some full shots and adjust the unit as needed. For 2gs I would think that should and could be much easier.

it is what it is and seems to be one of the few issues that we can live with unless we want to spend more than double on a GC2.

[Morini]

Agree that we shouldn't. I was pi**ed for a while, and you have all the right to be. It felt like a hack, but once I saw how accurate it was, I moved on.

Lately, I am too lazy to bother chipping, so I just eyeball and stripe a 7 iron. I generally get it right on first or second try.

There are some things you could do to speed things up:
1. Put screws in FMJ (saw your post about this somewhere else)
2. Mark the floor with tape or pen
3. Easiest of all for you, since you already use an alignment laser, just note where the laser points on screen when unit is correctly aligned, aim the unit there next time, no need to chip.