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

[Steve Jones]

For the base of my crankup I just used a 4-foot bubble level.  I checked the
level in both directions on each leg (ie. first measured with one end up,
then with the opposite end up), and split the difference in readings on each
leg.  After adjusting the nuts, all legs were reading the same both
directions.

73,
Steve
N6SJ


-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Roger
(K8RI) on TT
Sent: Saturday, July 22, 2017 10:00 PM
To: towertalk at contesting.com
Subject: [TowerTalk] Be Careful With the Tolerance in Laser Levels (Tower
base leveling.

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

-- 

73

Roger (K8RI)


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