If anyone is looking for a laser range finder
This is a bare bones model, but it's only $129. http://www.midwayusa.com/...finder-8x-black-gray
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General BASE
http://www.midwayusa.com/...finder-8x-black-gray
Re: [TomAiello] If anyone is looking for a laser range finder
hey Tom, i have never used one, from what i have read you need one with a hypsometer to measure height or is that not right? For measuring a crane for example
Re: [Dadsy] If anyone is looking for a laser range finder
I use a laser rand finder for cranes and it works fine. As soon as I get a jump-able height at any point on the crane i'll climb it and range top down to get a more accurate height.
That's a good price for a range finder, if anyone buys one please post your findings here.
Re: [dan_inagap] If anyone is looking for a laser range finder
how about from from the ground up, or always top down?
Re: [greeny] If anyone is looking for a laser range finder
it has been a long time since I did trig. your math works for a 90 degree angle at base of A and B. do you recall the formula if it is not a 90 degree angle?
Re: [greeny] If anyone is looking for a laser range finder
i thought i posted this back in the day, but i emailed it to some local crew... since i'm in a giving mood, i'll copy it here... a breakdown of quick height estimating that might come in handy. this example is for a tower obviously, but applies to anything. use or discard at will. 
In reply to:
Hello all. I was bored at work and thought you might all benefit from this.
***** would always hassle me when shooting the top of a tower from the ground if I was not at the base, stating that my numbers would be way off. While recently shooting a tower I suspected was approximately 140ft, I decided to actually do the math to make sure it was accurate, as I’m not terribly excited about jumping anything much lower than that. Hopefully this will help you out if and when you next need to get a quick height assessment of objects.
This particular scenario as an example:
a tower with 7 flanges (20ft sections) so appropriately I deduced it to be ~140ft.
I stopped outside of the fence (approx. 20-25ft away from the base) and shot the top of the tower with my laser and acquired the best reading. My laser reads in yards, 46.5 (139.5ft). Now, from initial reaction of being away from the base... one would deduce that the tower must be significantly lower than 139.5ft.
Well, here's the math. P theorem = A2 + B2 = C2
A = actual height
B = distance from the base
C = distance found by range finder
so we're solving for A obviously.
so here's our numbers:
C2 = 19460.25 (139.5 x 139.5)
B2 = 625 (25 x 25)
C2 - B2 = 18835.25
the square root of C2 - B2 = 137.24
so you can see with these rough numbers, in this case being 25ft away from the base of the tower ended up only giving me a difference in 2.01ft in the actual tower height.
I accept that as a negligible difference. Obviously, with an object as low as this, even individual feet start to matter, but overall it is fairly accurate and by doing the math I get a warm and fuzzy.
Just as an example, I will put out there a taller tower scenario.
Say the laser reads 102 (306ft) and you are 60ft away from the base. You know this because you shoot the base of the tower from where you are standing and it reads ~20yds.
93636 - 3600 = 90036
the square root of 90,036 = 300.05ft
so from 60ft away, the error is only ~6ft.
Re: [TomAiello] If anyone is looking for a laser range finder
My old rangefinder crapped out and I have one coming in today from amazon.com that was only $80 =) I'll let ya know how it goes http://www.amazon.com/...ds=laser+rangefinder
Re: [Dadsy] If anyone is looking for a laser range finder
Dadsy wrote:
hey Tom, i have never used one, from what i have read you need one with a hypsometer to measure height or is that not right? For measuring a crane for example
The hypsometer provides two advantages:
1. It does the pythagorean math for you.
2. It does Law of Cosines math for you.
If you can typically stand even with the base (impact area) of your object, the hypsometer is probably not worth the extra money. A simple laser and 15 seconds worth of math is a good approach. But if you are frequently measuring things where you can't stand even with the base of the object, then the hypsometer may be a wise investment, because even if you are good with the Law of Cosines, you still have to measure angles to get started.
This is the unit I use, and it treats me well.
~ Chris
Re: [TomAiello] Weaver Black & Grey
The ad says out of stock and back ordered... I used to own a cheapie Bushnell, worked great,
think I sold it to Kege, because one of my jump
buddys gave me a nice/expensive military laser.
I agree with Blitz that shooting objects from the
ground tells you most of what you need to know.
I personally think low freefalls are when 6 feet
this way or that way start to make a difference.
Attached is a screen grab from running a Google
shopping search for Bushnell Laser Range Finder.
It appears there are sub-$100 options available.
Re: [seekfun] If anyone is looking for a laser range finder
A hypsometer has an inbuilt level calc, so when you log the base and top points of the object, it also knows the angles the readings were taken from, and does the math from there. You can size the object at a distance, (within range limits). Unlikely you'll get a hypsometer for the price Tom's posted. Add a few hundred $.
Re: [Dadsy] If anyone is looking for a laser range finder
Ground up works fine, but I like to range top down on lower jumps anyway in case there is some swing in the boom (while climbing) and the distance to impact changes.
Re: [psf] If anyone is looking for a laser range finder
psf wrote:
it has been a long time since I did trig. your math works for a 90 degree angle at base of A and B.
do you recall the formula if it is not a 90 degree angle?
Pythagorean theorem (c square = a square + b square, where angle between a and b is 90 degrees, http://en.wikipedia.org/.../Pythagorean_theorem) is simplified equation of law of cosine (which states that c square=a square+b square - 2*a*b*cos(gamma), where gamma is angle between a and b http://en.wikipedia.org/wiki/Law_of_cosines).