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Anyone Have Experience With These?

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(@plumb-bill)
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I obviously wouldn't trust them for any tight work, but we have a lot of topo in the woods to do:

https://www.amazon.com/Degree-Prism-TOPCON-SOKKIA-Station/dp/B07SS48NN7/ref=sr_1_1?keywords=mini+360+prism&qid=1567519703&s=gateway&sr=8-1

Just wondering if they're as crappy as the price suggests?

 
Posted : September 3, 2019 7:17 am
(@va-ls-2867)
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Looks like a knock off of the Leica prism that only has 3 good faces for vertical.

 
Posted : September 3, 2019 7:49 am
(@plumb-bill)
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@va-ls-2867

Depends on your error budget, they'd be OK on all faces for forrest topo, etc.?ÿ?ÿ

We're a Trimble shop these would stick out as obviously being the "rough" set.?ÿ We don't even set?ÿ high quality project control with the Trimble 360s.

I'm mostlywondering about the durability, does one drop mean shatter?

 
Posted : September 3, 2019 8:16 am
(@eric-kara)
Posts: 167
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We sell them from time to time for cheep monitoring prisms. There are 100's of Chinese knockoffs and you never know what your getting.

They work in a pinch, but if you drop them or if they get wet they will fog and/or break.?ÿ

Some even have the same pointing accuracy as the Leica version so, 1.5mm. So they are better than 95% prisms on the market. This one looks like its " 5" ", but that is probably a posting error and not the prism's accuracy.

But honestly, these would be terrible for your application. When working in trees you want a bigger prism, not smaller.?ÿ Your robots ability to track this prism will roughly be cut in half. Great for construction layout, not great for topo.

 
Posted : September 3, 2019 8:42 am
(@rpls-2)
Posts: 105
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Not with that one but I have one of these:

https://www.ebay.com/itm/Brand-New-360-Degree-Reflective-Prism-For-Trimble-Total-Station-360-reflector/302201977004?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D20160908110712%26meid%3D442d1d203e85434a8151f347afffcb4b%26pid%3D100677%26rk%3D1%26rkt%3D30%26sd%3D280755261161%26itm%3D302201977004%26pmt%3D1%26noa%3D0%26pg%3D2385738&_trksid=p2385738.c100677.m4598

I paid about $99 for it. After testing each prism face, its less consistent than my $2,500 Trimble MT1000, but only by about 0.002'.?ÿ Not sure which seller I got mine from but it looks the same.?ÿ

 
Posted : September 3, 2019 8:44 am

oldpacer
(@oldpacer)
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I would suggest the full size 360?ø Leica knockoff if you are going to use it in the woods. The mini lacks the reflector face area needed to quickly find the holes between the leaves in wooded areas.?ÿ In my opinion it's 1/4 of the quality for 1/10 of the price.

 
Posted : September 3, 2019 10:05 am
john-putnam
(@john-putnam)
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@va-ls-2867

Jason,

While the older full size 360s vertical precision does vary depending on which face it sees, the amount in negligible for all but the most stringent of applications.  I did a significant bit of testing with them quite a while back.  The difference was slightly less than 0.01'.  I'm not aware that the Leica mini 360's have the same issue.  There is no indication on the one I have.

 
Posted : September 3, 2019 11:43 am
john-putnam
(@john-putnam)
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My real world experience with the true Leica mini 360 is mixed.?ÿ My TPS1200 and MS50 instruments tend to pass right by them in power search.?ÿ Other that that, they stay locked once you find them.?ÿ Also, the quick release GAD is about twice the size as the prism.?ÿ My original plan was to use them on 25' level rods to get it above the vegetation.?ÿ The problem being that it is hard to use the guide lights when the prism is 19' higher than my eyes.

 
Posted : September 3, 2019 11:49 am
(@plumb-bill)
Posts: 1597
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@eric-kara

Thanks Eric, this is very rough terrain, so cheaper is probably better.

This may sound odd but with the Trimble it works really well in the woods with the mini -30 prisms.  If you can see the robot it will lock onto you, and with the brush we're never more than 300' away...we actually leave a guy at the robot for pointing.  A robot wouldn't even be necessary for this work, but we already have them so why not use them...

 
Posted : September 3, 2019 11:59 am
(@va-ls-2867)
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@john-putnam

The one I had when running a 1200 10 years back, there was more than a 0.02' variance from arrowed face versus non-arrowed face.  There were some discrepancies between two crews doing stakeout that came to light when trying to check in on each other, the one cheif didn't know about the variance between the faces.  I had to tell him that's why there were yellow arrows on the top of the prism for the 3 good faces to carry vertical.  In my neck of the woods when you're dealing with 0.3% or less road profiles, you can cause a flood in those 0.02'  😆 😆  

 

 
Posted : September 3, 2019 11:59 am