Land Surveyor Forum

Replies

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  Billy Brooks July 23, 2016 at 4:05pm

  Good Idea  Ted, The Texas summers will cause nightmares in the day, Tried to use umbrella's when the wind let you,they really help in hot,hot areas, with a TS,  stops all that warping and expanding on the sun side and the shade side too,  on the gun or tripods. Just had to watch out for that Texas wind, the umbrella's  would fly away. sometimes had to drive spikes in ground then tie or tape the umbrella's rod to the spike, Strong wind in Texas had to put sand bags on feet of tripod, so the gun didn't get blew away too. It's a wayward wind whatever that means. sand bags will work on the umbrella's too. What ever it takes.
• Land Surveyor

  Ted Link July 21, 2016 at 10:29am

  If you are doing precise work, all bubbles & calibrations need to be done often & weather, temperature & wind need to be considered. We are working at night to reduce some of the error we are seeing during the day.
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  cut fill July 9, 2016 at 8:40pm

  Great topic... It seems like maintenance of tribrachs and other equipment has become a lost art...
  • Seeking Employment

    Maurice Heter > cut fill July 9, 2016 at 8:58pm

    Yes it has. The Trimble traverse kits are the hardest to adjust. I have to send them into the nearest dealer for repair/ alignment of the optical plummet. Leica is a little easier to deal with.
• Not a Surveyor

  William Robinson July 3, 2016 at 6:40am

  We used to check the optical plummets by setting up (Tripod and instrument) and placing a note pad under and central to the optical plummet. Draw a pencil line outlining the tribrach on the tripod seat, Level the tribrach via the instrument, (Need a second person for this part of the operation) Look down the optical plummet and guide the second person to intersection or centre point of optical plummet and put a pencil dot at that location. 

  Rotate tribrach and instrument until next 3 corners of tribrach fit into pencilled outline and repeat levelling of instrument and pencil dot procedure.

  Rotate a second time and repeat the above.

  You should now have 3 pencil dots which should be more or less on top of each other if the optical plummet is good. Also this is a good way to check the bulls eye tribrach level against the instrument level.

  If I was setting up targets over stations or if I was Traversing for example, I would never just set up a tribrach for a Target using the tribrach alone. I would always use the instrument to level up first and then place my targets in the tribrach.
  • Not a Surveyor

    William Robinson > William Robinson July 3, 2016 at 10:06am

    I've just realised that I forgot to mention what happens if the pencil dots don't line up. If you end up with 3 pencil dots that don't line up they and they are far enough apart they will be in the shape of a Triangle. Draw lines between the dots to make a Triangle and then strike lines from each of the vertices straight down to half base on each side. The intersection point of the three lines marks where the optical plummet should be focusing. If the dots are pretty close together and it would be difficult to make a decent sized triangle then you haven't got anything to worry about.
    • Seeking Employment

      Maurice Heter > William Robinson July 3, 2016 at 12:40pm

      Thanks for your help. I have been doing this. I find that the Trimble tribrachs are odd to work with since they have no optical plummet, only the circular bubble. Also the optical plummet is part of the carrier which can hold the target. I think all the servo instruments have change the way we look at tribrachs. The tribrachs have to be more robust to handle the torque from the servo drive on the instruments.