[TowerTalk] Be Careful With the Tolerance in Laser Levels (Tower base leveling.

[Clay Autery]

I'll use a combination of plumb bobs and water tubes....  gravity is
remarkably more consistent than laser levels made in China.  ;)

______________________
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 7/23/2017 12:00 AM, Roger (K8RI) on TT wrote:
> When using laser levels there is a tolerance of +/- Something per ft,
> yard, 10 feet, etc.  It's often a lot more than acceptable for
> leveling a tower base.
>
> I have two, a transit and a level.  Setup and calibration are
> critical.  I have a plain old combination bubble and 3 digit, digital
> level. Two digits to the right of the decimal is more than enough. 
> Calibration is easy. Find something close to level (level is not
> necessary, but convenient) The two points should be about the same
> distance apart as the bolts. You can even use those bolts, getting
> them close with the bubble. Then you simply turn on the digital mode,
> set the level on the nuts and push a button, swap ends with the level
> and push a button.  The digital level is now zeroed.
>
> NOTE: The calibration points must be STABLE!  The nuts can not be
> loose. The digital level properly zeroed is more accurate than the
> laser transit or level you can purchase at the big box stores that
> require much more care in calibrating.  A surveying laser transit (A
> lot more money) is accurate, but still takes care in calibrating.
>
> Were I to go that route, I'd rent a surveying transit, but being
> frugal (some would say cheap) and a bit lazy, I'd use my digital
> level. I have it, know how to use it, and with a fresh 9V battery in
> it being the only cost.
>
> I've seen manufacturer's suggestions to use a plumb bob. Now depending
> on where you live, dead calm days may be rare. We might have 3 or 4
> days a year where it's dead calm long enough to use a plumb bob on a
> 60 - 100 ft tower and a plumb bob is far more work than these other
> methods
>