"yourname" wrote in message
news:TLCse.9130$aR1.5312@trndny02...
christ, whats wrong with a water level? 10 bucks worth of fittings and
clear tubing, a length of garden hose and you are good to go.

The real problem is that most people don't know how to use a water level.
That's why those silly things with the buzzer on one end were made. (BTW...
they suck. ONE use and two months of storage destroy them, due to corrosion
and mildew on the pickup contacts. Even with the "cleaning brush" they
_sometimes_ supply with them, you cannot keep one working for long in a very
damp climate.)

A right-good water level is made with a long length of transparent tubing
(about 1/4" to 3/8" i.d.) and a large vessel at the "home" end. The vessel
should be twenty or more times the total volume of the hose to make the
system both easy to use and accurate. A gallon milk jug works fine for most
lengths.

Adapt the lid of the jug so it snugly holds the tubing all the way down to
the bottom of the jug. Fill the hose completely, and fill the jug to at
least the 1/2-full mark. Purge all bubbles from the hose. Provide a clamp
or plug for shutting off the free end of the hose so the water doesn't pour
out when you move it around or set it down.

Place the jug at your "home" reference, and note the distance from its water
level to the "level mark" you want to establish. Then just move the other
end of the hose to the various locations where you want to strike marks.
Measure up or down from the hose's water level the same distance you
measured up or down from the jug level.

If you let the water "settle" between moves of the hose (for say five to ten
seconds after it seems to stop moving), you'll be within a 1/16" or so
everywhere -- even up to a hundred feet from the jug. Bubbles in the hose
will drastically impair its accuracy.

LLoyd