Hi all, I thought John Ganter's comments (on Cavediggers) on how to best use a Disto would be interesting to you all.
Yvonne -------- Original Message -------- Subject: [CaveDiggers] Laser targets, etc. Date: Fri, 25 Nov 2005 09:13:50 -0700 From: John Ganter <j...@darkfrontier.us> Reply-To: cavedigg...@yahoogroups.com To: cavedigg...@yahoogroups.com >> How reflective was the target you used? > > > The target should be non reflective (not glossy) - this kind of rangefinders produce errors if the target is reflective - e.g. the recrystalised concretions in a cave. > > The very matte surface may produce error too - as dry dark mud. When I first saw a Disto in a cave, the user was very specific about a yellow survey book as target. Later, when I bought a Disto Classic 5 I learned that yellow is not a good target. From the manual: "Best targets: Use target plate 563875 (DIN C6) rsp. 723385 (DIN A4). • White surface: to 30 m • Brown surface: from 30 m on Reduced range: mat green and blue surfaces (also by plants or trees)." Generally, our point person uses their hand as target. They say "Hand on station" then the Disto person says "Eyes away." Point closes their eyes or looks away, then Disto says "Laser" and makes the reading. The laser is reasonably eye-safe, but it is good to avoid exposure especially for dark-adapted (pupil wide) eyes. I prefer a tape for muddy conditions or for surface surveys in brush. The best thing about the Disto, from my perspective, is being able to measure ceiling heights for profiles. Awhile back I was surveying in a twilight area just inside an entrance. The old map said 120 foot ceiling height. The Disto said 252 feet. Another time I was checking some high holes and noticed a 20 foot difference between the lip and an invisible (even with a million candlepower spotlight) back wall. We did an aid climb and picked up 120 feet of passage. The Classic 5 fits in an Otter Box 9000, if you remove the foam on the sides. Another piece of foam can be put in the lid to hold it firmly. Sure comes in handy around the house and yard, e.g. measuring windows for blinds... --JG _______________________________________________ Texascavers mailing list Texascavers@texascavers.com http://texascavers.com/mailman/listinfo/texascavers_texascavers.com
