Distances - Driver

[SingleDigit]

I just got my new ST on their latest promotion and set up a basic sim in my garage. Out of the box I started with a PW and my distances looked good. I worked my way through my bag and noted that my driver was way short. I kept at it knowing that I didn't hit every ball clean. After about 20 shots, my shots barely increased in distance but was still about 40-50 yards short.

I went to WGT to play Pebble and came back to Practice mode. I noticed that my distances shortened across all irons (~10 yards). I adjusted the elevation and it seemed to have worked, except for my driver still.

Has anyone else seen this? I am setting the red dot at the base of the tee. Am I doing anything wrong or does ST just not work with a driver?

[doublebogey]

If you upgrade firmware to 1.4 using PC app driver distance supposed to improve ~4%. But yes ST does seem short on drivers (I've tested all my clubs on range w ST and they all seem pretty close except for driver - and maybe 3 wood). I was playing a round last week and my drives are def 20+ yards longer in real life vs ST. Some have attributed to ST not giving right carry distance to lower spin drives (I see on my ST my backspin on drives typically in low 2,000's which should allow ball to carry further in real life but not quite so w ST).

[Joko]

I'm going to take mine to the range next week during a lesson and see what the instructor thinks.

[SDL]

I also just picked up a ST in the latest promotion, and I am experiencing similar problems with the driver. In fact, I seem to be getting similar distances with a 3 hybrid as with a driver on the ST range. I've also seen a few really high backspin rates (over 10K) on an occasional drive although most are around 2K. I'm using an iPad and can't upgrade to the 1.4 firmware until the Apple version is released, so I'm still hoping the new firmware will make a difference with the driver.

How is the driver distance on WGT?

[luv2golf]

Drivers horrible on WTF (sorry - WGT). Why don't you just connect ST to your CPU and do firmware upgrade. You'll get the firmware on your ST but just older IOS version on your ipad.

[SDL]

Good idea, Luv! So I downloaded ST 2.1 for the pc on a separate computer, but what's the next step? Is there a way to connect the ST and PC through Wi-Fi or is it better to connect via USB?

[luv2golf]

Just connect via USB same cable you charge your ST with.

[ernie18]

everything up to 3 wood works good for me (gw-6iron, 5 hybrid 3hyb, 3 wood) i for some reason cant hit a good drive. so im not sure if its me or the unit yet. though i did have good drives on e6 while playing.


ive read to tee it back an inch behind the red dot as well as put the logo towards the red dot so it can take a picture better of it.

[SingleDigit]

Thanks guys. I am software version 2.1 and my unit firmware is 1.350. Do I need to update the firmware? I am running on an iPad so do I need to do what SDL did? I am headed to the range today to test for the first time and if my drives are as bad as what ST is saying, its going to be a long day!!!

One final thing. Is there a way to delete shots from your history as ST just missed the shot or I set the ball up wrong as it shows 0 spin for example.

[Sascha1818]

on apple 2.0 version you can delete the shot you just took. The X on top of the screen. On PC 2.1 and next apple 2.1.1 you can delete any shot in the session before you save it /close it.

[ernie18]

yes for the 1.4 firmware. for apple products i dont know, but i know it was a simple install with the pc version maybe if you have a pc just do the install and that way the firmware gets updated ?

[m3w]

Driver distances are definitely way short. I compared mine to a GC2 on several occasions. Average driver distance on GC2 was around 230y, on Skytrak it was around 170y. Returned it as an RMA. The second unit I got showed the exact same yardage as the first. Needless to say, I returned that one too.

[Mitch Cumstein]

I'm seeing the same thing with my new SkyTrak running 2.1 with 1.4 firmware. On the course my drives are ~230+y but they're about ~210 on ST.

[Sascha1818]

Yes Seth said there will be a small tweak in 2.1, nothing major.

[Wyzyguy]

New here. Not sure if this has been discussed already but... What makes the driver distance incorrect? Does it not capture the ball speed correctly? Is it a matter of a different modeling software? My guess is that my ball speed with the driver is low by about 7-14 MPH on a good strike based on #'s off TrackMan & TruGolf.

[bbb287]

I also am seeing a 7-10 MPH difference in the reported ball speed on the ST vs a Zelocity device that I have. I have a 'demo' unit and opened an incident with the SkyTrak support group. Was informed that it would be 2-3 days before they got back to me....I am using the latest PC version, so the 'improved' distance for the driver is already included.

During my testing, I was able to have both the ST and the Zelocity capture data from the same swing, so it was a direct apples-to-apples comparison.

[Mitch Cumstein]

It's possible a ball speed issue is present for all clubs but the effect in terms of distance is smaller. bbb287 - are you seeing the same thing with all clubs?

[bbb287]

I am seeing slightly lower ball speeds on the irons 5 & 6, approximately 2-5 MPH. The short irons appear to be correct. Hybrids (4&5) are low by 5 MPH. My 4 wood is also low by 4-8 MPG....
So with my ST device, only the short irons appear to be correct, the rest are always reporting lower ball speed MPH, as compared to the Zelocity device that I have access too.....

[luv2golf]

Yes, there's an IOS update coming, not sure why it's been 2 plus weeks for the PC version but they can't get the IOS update out?

Again, makes me question if there will be any sim software out before February 2016.

Maybe they are waiting for the PGA show?

[TorchRedRob]

This is interesting. I'm curious to hear from davray666 how it might be possible to have a big speed miscalculation like this, from an image processing standpoint. Especially if it's only with certain clubs and/or ballspeeds.

[davray666]

TorchRedRob to give an accurate answer on that question I would need to know how Rapsodo calibrates the units during manufacturing and how the lens correction is applied.
I don't, but here is a theory specifically targeted towards the problem of ball speed accuracy difference between clubs.

The lenses ST uses are wide angle and low cost. The wide angle creates a fish eye like distortion that needs to be corrected before any vision processing is performed.
The low cost lenses typically have a large non linear geometric distortion that requires an individual calibration step during ST unit manufacturing. There is more like image sensor position error introduced during manufacturing etc ...
This all boils down to the need for a unit calibration where correction data is stored in the unit it self. I doubt that Rapsodo does this, but I don't know.

If the calibration/correction is not done individually? You might get a non linear error on position. In the case of driver vs iron where the assumption is that the driver creates a higher ball speed. The ball image will be captured further away from the image center where the distortion is higher. If this is incorrectly corrected because they use a static correction map, you might well get a speed error for drivers while irons are OK. Typically this would just add to the overall error and still be acceptably accurate because the lenses are probably close enough, but if you get a particular bad lens then it can create big deviations in a totally unpredictable way.

If the driver distance is incorrect due to unreasonable back spin numbers, then the root cause is different. I did a side by side GC2 vs. ST a few days ago.
My ST unit has been tested against Trackman and it is accurate for everything except high loft wedges and typical short game shots with those. But that is a unit design limitation and not related to the unit I have. You all have that problem.

What I did observe was that GC2 vs. ST data was very similar for all shots I tested except those where you hit it in an unusual way. Say a 7 iron that is hit thin resulting in high ball speed, high back spin and low launch angle. There I could see significant diff. in GC2 vs. ST for both back spin and distance.
So I suspect that ST will make a best effort to measure the spin. If it can't or if the spin number it measured is unreasonable it will show you a typical number derived from ball speed and VLA.
If I can find the time I will do a bit more testing on this ...

[Wyzyguy]

TorchRedRob
I did a side by side GC2 vs. ST a few days ago.
My ST unit has been tested against Trackman and it is accurate for everything except high loft wedges and typical short game shots with those.

Hello davray666,
To be clear. Your driver & 3W #'s are equal when comparing ST , GC2 & Trackman?
How about ball flight curvature? Thanks for all your input. I am a new user and this info is very helpful.

Thanks. Wyzyguy

[davray666]

You might want to check this out and especially the attached XL sheet. Should answer all your questions.
But keep in mind that based on what people are saying here. This is valid for my unit and not necessarily yours.

http://golfsimulatorforum.com/forum/skytrak/38238-st-versus-tm