Labradar V1 may need a service

[bigHUN]

I was browsing through many subforums have not seen a better spot for my questions, but right here to ask the real experts

I got this orange unit last summer from a second hand. Primarily to get some sense along my load development. For my airgun subsonic speeds I am using the FX doppler radar for years already. So, me kind of educated with radars.

Unfortunately.... I noticed only today, that the unit - reads the speeds "maybe normally" from multiple distances - but calculates most of the Average full with errors.
And that of course throws the ES/SD out of tracks.

Today, in this case I had a larger shot string monitoring and searching for best seating depth.

46.2 grain Varget, 155 gn Sierra Match 2155, multiple seating depths starting from minus 0.020, 0.026, 0.032, 0.038, 0.044 thau from land. (Lapua brass prepared).

Here is a screenshot that may explain it better, if nobody have seen it before.
The radar is reading, there was no interference from other shots I am using a wire trigger, the distance to barrel or muzzle doesn't effects the bullet speed reading. The error is in calculating the Average.
In my eyes this is an algoritam error. The firmware is latest available. The Labradar app and the SD card *csv file showing same numbers, so the calculation comes from the unit alone.



None of those Average speeds 3000+ shall ever exist.

Q:
Do we have a Labradar Service anywhere in Toronto or GTA, or in driving distance at least, if I can save myself time vs mailing the unit.

 

[ghughes]

Im not an expert but,
Try calculating the Vavg from the individual vel. values, I think you'll find it's correct.
What do the V10, 20, 30 represent? Are they down range calculations?

 

[legi0n]

the average looks good to me. I averaged the 11 velocities visible in your screenshot and I got 2998fps.
the V10, 20... are the velocities at the 5 distances you set up in the unit and are not used to compute the average

 

[Buck1950]

Your screenshot doesn't include shots 001 - 003, so we can't 'see' if the 'V-average" is accurate, but I get close to the same as legi0n. I don't think the 'V-average' is meant to be the 'average' of those 3 'V' speeds. But I don't have a Labradar, either.

 

[bigHUN]

The app screen is a bit missunderstandable if you never use it before.

This is for example a "series #13" which had 14 shots.
What is circled the multiple speeds downrange with a red pointer is a shot number 14.
Whichever shot number 11 or shot # 9 or shot # 5 you click on it and it will display the details for that shot only, and looks like as the next line.
The V10-V20-V30-V37-V44 are downrange distances.
In my case there are these measured values: 2976.5+2952.8+2927.4 = 8856.7 divided by 3 = 2952.2 is the Average of these three speeds, and not 2999.7
Unless, the 2997.7 is a speed at the muzzle ??? but then shall not be called "Vavg"

Every each speed exceeding 30xx I circled with red, none of the downrange numbers would generate 30xx.

Anyway, thanks for chiming in, I smell some errors in calculation, I will send it out for service.
Sent them email for mailing instructions.

My biggest issue is ... I was calculating the powder testing last week based on Labradar data, based on ES/SD.... Uhm, not much to say there.

 

[Longstud]

I don’t think your unit has any problems. The average is derived from the reading at your first selected distance and the number of shots in the string. The plus and minus just denotes how far above or below that shot lies in comparison with the calculated average. If you’re wanting to shoot1000 yards I’d be trying to shrink the ES and SDs lower. Chronographing loads with different seating depths is also not going to give real ES or SDs either. I hope this helps

 

[bigHUN]

I don’t think your unit has any problems. The average is derived from the reading at your first selected distance and the number of shots in the string. The plus and minus just denotes how far above or below that shot lies in comparison with the calculated average. If you’re wanting to shoot1000 yards I’d be trying to shrink the ES and SDs lower. Chronographing loads with different seating depths is also not going to give real ES or SDs either. I hope this helps

I agree with that the amount of powder load - plus the brass preparation - drives the ES/SD.
The seating depth is only a next step when the projectile "jump" effects the barrel harmonics.

Until I wait for Labradar answer I will make couple new powder loads with less amount, I want to stay away from speeds coming close to 30xx.
Speed kills the accuracy, and I can see that on the group size.
A 45.8 gn Varget (with lower speed and larger ES) was much tighter group then the 16.2 gn Varget (at higher speed but lower ES).
And this where contradicts to big shooter claims - to work the load development with lowest ES....

 

[bigHUN]

Question:
The LR settings for signal sensitivity, distance from barrel, also the alignment towards the target - shall not throw higher speeds numbers?
I guess....
So far I don't have missing shots, only higher numbers.

 

[bigHUN]

I got some comments in pm's but I cannot attach screenshot images there, so I will place them here.

This is my Samsung tablet screen, I cannot fit them all but scrolled down where starting the shot string.
I will randomly select some shot numbers. For example #1, #4, #9. In these case the Labradar picked up the muzzle speed plus two more ranges down the line.

 

[legi0n]

the Vavg is the average of (all 14) numbers in the red box


3014.6 + 3006.6 + 2990.6 + 2994.0 + 2985.8 + 3006.5 + 2982.8 + 2998.8 + 3004.2 + 3008.2 + 3013.8 + 2988.7 + 2989.0 + 3012.2 = 41995.8
41995.8 / 14 = 2999.7

 

[257Wby]

In addition to Legi0n comments.
The Series data is summarized in the green headings .
V avg. is the average for V0 ( muzzle velocity) of the 14 shots on the series.
V10, V20,V30, V37,V44 are the Averages for the 14 shots at the various distances the user specified for the series.
MAX, MIN , Ex SP. ,STD. DEV are calculated from the V0 data for the 14 shots .

 

[bigHUN]

....

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Thanks guys.

 

[bigHUN]

In contact with the MFG, they will modify the GUI for better interpretation of numbers.