>
> There was a message thread here a few weeks ago about how to plumb a
> tower, with several suggestions ranging from using a plumb bob to a
Plumb bobs are pretty much useless except indoors or over very short
distances.
> laser level to a transit. I've been installing the base for my new
A laser level would be lucky to be pushing the limits of acceptable accuracy
while an optical one would do much better. OTOH the optical transit is far
more expensive. I have a laser transit and with care it can hit one inch in
a 100 feet, but that depends on the skill of the user. One of the more
expensive (Mine was a long way from cheap) self leveling units might be
better, but I think the optical is probably still the best. Most laser
levels are acceptable only over short distances, great sounding adds aside.
<:-)) I have a 4' digital level that reads to the nearest tenth of a
degree.
> freestanding tower the last couple of days, and since the legs taper
> toward the center I needed a fairly precise way of making sure all three
> base legs tilted the same amount. I remembered that I had previously
> bought a digital angle gauge to use for setting blade angles on a table
> saw, so I dragged it out and it worked great. It has a magnetic base
> that attached easily to the steel tower legs, and the rated accuracy is
> 0.1 degree. I have no way of verifying the absolute accuracy of the
To get that accuracy you probably need to calibrate it for each use. My
digital level just requires going into set up, measuing one direction
(doesn't even have to be level), puching a button, turning the level 180
degrees and punching the button again. It electronically takes the
difference and calculates level.
> thing, but I did spend quite a lot of time checking the repeatability
> and I can confirm that it is indeed within +/- 0.1 degree. It really
> made the job very easy.
Repeatability is nice, when going for the same angle on each leg as long as
you are not fussy about the angle.Going for "tall" you need actual angle and
not just repeatability.
>
> I'm sure that there are several similar models, but the one I happen to
> have is made by Wixey and it is available from several online suppliers
> for less than $40.
Most of the ones I've seen that give an accurate measurement are far more
expensive than the ones most of us use. Me? I can usually figure one agaisnt
the other and come out with acceptable results.
73
Roger (K8RI)
>
> For what it may be worth ...
>
> 73,
> Dave AB7E
>
>
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