My Lab Radar

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jasmay
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My Lab Radar

#1 Postby jasmay » Tue Dec 15, 2015 9:47 am

Is anyone using one yet?

Anyone managed to sneak one out of the states to play with?

Matt P
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Re: My Lab Radar

#2 Postby Matt P » Tue Dec 15, 2015 11:01 am

Not yet but been told the mine should ship Jan/ early Feb but we'll see :roll: :roll: .
Matt

pjifl
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Re: My Lab Radar

#3 Postby pjifl » Tue Dec 15, 2015 9:55 pm

I have had one for about 3 weeks and am experimenting comparing it against different Magnetospeeds.

I was going to wait until I had done more comparisons before mentioning this but have done two comparisons in fair detail so here goes.
Correlation between the LR and both these MS units is exceptional. Maybe it is a fluke which is one reason I wanted to test more MS units before reporting the results. Which is the most accurate I am not certain but knowing how LR works I think it should be possible to derive more accurate results from LR Doppler readings. MS uses a short baseline and there are possible triggering inconsistencies and varying offset from the bullet. Having said that I think MS is also exceptional but there may be greater differences between units.

Mean difference over 24 shots for one unit is about 4 f/s. and the other unit over 12 shots is about 1 f/s.
SD of the error in each case is about 2 f/s. An SD based on 12 samples is not a good idea but these results give me a lot of confidence in both.

I have tried to attach two graphics but this may not work. I have never attempted it on this site before. The second comparison starts in a freshly cleaned and very lightly JBd barrel which accounts for lower V initially.

It is only now that I understand how the LR works. It does not acquire the velocities in the bullet track until about 10 yards out because of a time lapse between muzzle blast detection by its built in microphone and Radar signal powerup. But then it takes a V reading every milli sec out to about 70 yards.
So the only way it can 'measure' muzzle V is by doing some fancy maths. I imagine it does a correlation then extrapolates back to t = 0. I see nothing wrong with this and since it depends on many readings I would expect high accuracy.

The catch is about when the muzzle blast is heard by the microphone, because every ft from the muzzle accounts for a lost milli sec for our typical rifles.

The unit can be set for 6in, 12in, and 18in from the muzzle. I used it further away so expect maybe 1 or 2 f/s zero error. At the moment I am mounting it on a camera tripod but must make something that goes lower.

Now for some pros and cons. And before I do this - again - I am very pleased to have the LR AND the MS. The following are not really criticisms - rather they are different properties. I do not think the LR simply replaces a MS.

1/ MS has to be turned on and armed just before shooting. Need to reach up and forward and and look up at lights and buttons.
MS can be prepared beforehand and be on the barrel ready. Just plug in the black box before the shoot and it is close and within reach and down at hand level. (easy to forget to start, however)

2/ Reading LR during a shoot is much harder and disruptive while MS unit is in a convenient spot on the mound.
I suspect LR could be set up so it was nicer to use from a table.

3/ LR does have to be aimed fairly accurately or it will not acquire. The idea of just plonking it down behind a shooter is flawed.

4/ Placing LR close to a muzzle is not as easy as it sounds. Especially when one uses large complex front rests or bipods.
Which makes it harder to turn on and control and read when shooting and gives more zero error.

5/ The multiple readings out to about 80 yards seems to me to be of limited value. Examining a 'Track' as they call it shows an increase in variation in V readings starting at about 50 yards (Much the same with 308, 7mm and 6.5mm from what I have seen). I think people who want to derive BC from these readings will find they will not have enough essential data to give accurate BCs. Pro units follow a bullet all the way to the target and these will do the job. In any case, I think many shooters place far too much faith in BC. Accuracy is more important.

6/ Sometimes LR picks up adjacent shots - something MS never does.

7/ To many the LR will always be favored because it can not change barrel vibrations. I find with a very heavy barrel MS seems to have little effect but would expect it to be a problem on many lighter barrels.

8/ LR bypasses the problem of reaching around large barrel weights and tuners.

Perhaps I have forgotten a few things.

Now to send and hope the files (graphs) make it.

Peter Smith.
You do not have the required permissions to view the files attached to this post.

AlanF
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Re: My Lab Radar

#4 Postby AlanF » Tue Dec 15, 2015 10:33 pm

Thanks Peter - very interesting.

You mentioned the LR needs to be turned on and armed just before shooting. Do you mean it needs to be armed before every shot?

pjifl
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Location: Innisfail, Far North QLD.

Re: My Lab Radar

#5 Postby pjifl » Tue Dec 15, 2015 10:55 pm

No need to arm it for every shot. It collects all in a series before you close it off.

But because it is supposedly heavy on batteries it will turn itself off if you are very slow.
This is all settable and OK to use but not like the MS where you almost forget it and battery lasts 'forever'.

But having to set it up beforehand, then turn on and arm it before getting down to shoot is far more complex than the MS.

Probably easier for another person to set it up and even call Velocities for you.

Of course it does record all Vs and this works very well.
The files it produces are very easy to extract and you can read them with Excel.
Downloading files is just like down loading pics from a camera with a USB link or else you can take out the SD card and read that.

There are a huge number of things being recorded per shot. You have to download the files to see all of these but the basikc info shows on a screen for each shot.
Like Vo, Vav and SD.
Additionally V10, V20, V30, V40 depending on how you set it.

I found setting it up fairly easy but it takes a little thinking closing off series and starting another on the mound.

It is well thought out.

Peter Smith.

Norm
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Re: My Lab Radar

#6 Postby Norm » Wed Dec 16, 2015 1:55 am

Very interesting.
About how much does the Lad radar cost?

pjifl
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Re: My Lab Radar

#7 Postby pjifl » Wed Dec 16, 2015 6:18 am

Here is one source showing US $560. But with a long waiting period.
I had an order in from the beginning when our dollar was much much higher than now.
I cannot help thinking that, like the original MS, after they became so popular there was a substantial price rise.

http://www.longrangehunting.com/store/labradar.html

More details are given here.

When I ordered, many of the 'extras' were not available like a low mounting plate amd carry bag. Both I believe would be worthwhile and after using a small tripod I intend to make some low mounting device like theirs.

Peter Smith.

jasmay
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Re: My Lab Radar

#8 Postby jasmay » Wed Dec 16, 2015 6:51 am

Fantastic info there Pete, thanks for that, the Pro's & Cons you outlined have some great real world implications.

shooter mcreid
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Re: My Lab Radar

#9 Postby shooter mcreid » Wed Dec 16, 2015 7:00 am

One implication is people who already own a V3 won't be rushing out to get the LR as the accuracy of the units seem to be very much on par. More sample tests will be required to confirm this but it's puts me at ease. Thanks Peter for taking the time to test it and post a report.

williada
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Re: My Lab Radar

#10 Postby williada » Wed Dec 16, 2015 12:06 pm

Excellent work Peter.

RAVEN
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Location: Adelaide South Australia (CTV)

Re: My Lab Radar

#11 Postby RAVEN » Fri Jan 29, 2016 12:16 am

Great info Pete thanx for your efforts
RB :D

dazza284
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Re: My Lab Radar

#12 Postby dazza284 » Fri Jan 29, 2016 10:09 pm

as these things transmit RF has the ACMA approved these LR units yet ?

agro
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Location: Regional Vic.

Re: My Lab Radar

#13 Postby agro » Sun Apr 23, 2017 7:55 pm

Has a LR been tested against the OEHLER 35P ??

pjifl
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Re: My Lab Radar

#14 Postby pjifl » Sun Apr 23, 2017 9:10 pm

In my opinion the LR is more accurate than anything else we will ever use. Three units have been used side by side now and often agree to the exact last digit and very seldom are 1 unit different. It is a whole new generation which is light years ahead of the older ones for accuracy despite the nostalgic reputation that people want to cling onto re Oehler.

The principle of operation lends itself to accuracy traceable back to the timing in the LR unit. There is no baseline error. It measures V DIRECTLY and does not calculate it by trying to take two trigger pulses and measuring time over a distance. All other Chronys do this and consequently suffer the sum of 3 errors for each measurement.

In addition, the LR takes a reading every millisecond and in effect averages perhaps 40 to come up with the final figure. No other Chrony does anything like that.

Peter Smith.
Last edited by pjifl on Sun Apr 23, 2017 10:12 pm, edited 1 time in total.

pjifl
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Location: Innisfail, Far North QLD.

Re: My Lab Radar

#15 Postby pjifl » Sun Apr 23, 2017 9:17 pm

Meant to add. As far as I know the units that have been and will be supplied to Australian users are identical to the US and Canadian unit as far as power goes.
Units for the EU are downrated. I don't know where the story of it being derated for Aust ever came from.
In any case, the only benefit to reading V further out from the unit by using larger power is a moot point. Trying to calculate BC from the short track is almost pointless for target shooters using known bullets and in my opinion is more of a selling point meant to impress people reading web sites rather than being of any real use. It cannot compete with a professional military doppler radar which can follow bullets all the way to the target and thus give proper BCs.

Peter Smith.


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