Basejumper.com - archive

This afternoon I went to one of my freestanders
that I had static lined before with the intent to
do a go & throw.

The internet said it was X height yet I wore my
Suunto just to be safe and wow it was 38 feet
lower than expected.

Sure damn glad I had a static line in my pocket

So how tall was it? 3,4 hundred? What?

Remember, the "internet" includes the highest appurtenance that the tower was ever approved for. That includes those big nut cooking microwave horns you like to hang onto as well as anything else that may have been there over the years. Or even was APPROVED to be there and never put up. Those freestanders you like to jump are almost always 14 feet off because of the horns.

Reported: 268'

Suunto: 230'

My limited experience completely matches
exactly what you said but this is the biggest
discrepancy I have ever seen. Wow.

Typically I do one of these to confirm height:
1) Laser, 2) Suunto, 3) count rungs as I climb.

You missed my joke. Static Line, 3, 4 hundred feet...

Oh nevermind.

You should have freefell.

Word of advice to any new jumper. Dont read any text that is Green.

-

That would be your 1st mistake . Believing something that you read on the Internet .
.

did you video it?
if so, how long was the canopy ride? how does it compare with other objects?

what I'm getting at is this...
there are a ton of factors that influence how a parachute opens and flies, so why be so fixated on the height? (at least after the first jump.) use your experience at the site to help guide your decisions. if you s/l an object and get xx seconds of canopy flight, then you can consider f/f.

just a thought...
ymmv

(Green's warning is more valid, in my mind, for initial jumps from an object. In that case, jump conservatively until you gain experience.)

ASR often tells you AGL without and with appurtenances in meters.

I have, on several occasions, disproved it.
Stephen, is this true that these recordings are approved heights, not actual heights?

~Jake

What are you talking about? 230ft is plenty of altitude!

+1

The suunto's using pressure, like most altimeters, so another possibility (i doubt it would cause that much difference though) is pressure change in your climb time. If the pressure in your AO went up a lot after you zero'd it would skew your height to look shorter than it was.

Edit to add:
Standard pressure in inHg is 29.92 and a general rule of thumb is 1 inch is 1000 ft, so .038ish increase in pressure after zero would mean your tower was 268 not 230.

The pressure will not change that much while climbing, or you are seally a slow one. Or then the weather is really not a jumpable one...
We have been doing loads with several SUUNTOs zeroed at ground, and at exits they ussually will show differences. The difference described here fits well to our findings. We ussually jump according to the one that shows the most alti, just for not getting scared of how low it really is :D
I think that the differences are mostly caused by temperature variations, as the SUUNTO assumes certain coldening when going upwards, which may not be the case if it's hidden under your clothes, zeroed at different temperature than when read at exit etc.

Main point, do not rely on single instrument only when determinig alti of a low object.

V

Was the base of the object 38 feet above sea level?

Always remember, if you're getting your information from any kind of aviation source (sectional chart, skyvector.com, ect.) that the altitude of an object is given in both AGL (above ground level) and MSL (Mean Sea Level).

On a standard sectional chart the altitudes are posted just to the right of the antenna icon. The MSL altitude is posted on top of the AGL, which is always in parenthesis.

+2

So you FF'd it then?

Exactly.
Tom...be careful relying on a suunto for an accurate measure on a low object , because they can show some signifcant variation, which can prove very significant on lower objects.
30-40 ft out on something >250 isnt the end of the world.
On something lower ( say 150ft)....that significance of that variation is more important !

Suunto as a guide. , yes, but I would never trust a suunto's measure as absolute ,especially on sub 250ft objects and /or where it was critical to know the exact height ....

I never take anything from the internet as gospel.

I am aware that heights are listed as MSL & AGL.

The green text makes my posts very easy to avoid.

I doubt pressure change, climb time was 10 minutes.

My Suunto does need new battery so it could be off.

Yes of course I got video, GoPro: 1 forward, 1 back.

At this point I AM willing to freefall from 230 feet.

The landing area at this freestander is wicked tight.

Given the winds and the LZ, static lining was smart.

Keep in mind I was solo and 30 miles from medical.

Attached are screen grabs captured from the video.

I will upload video of the jump in a very short time.

See: Sharing A Jump for more details.

count rungs

I agree and typed above:


Typically I do one of these to confirm height:
1) Laser, 2) Suunto, 3) count rungs as I climb.

I am a Newbie, thanks for the heads up. One of my great landings from my first Bridge Day was on this News clip that was sent to me, but so was your interview about your ash jump. Not sure if you have seen it but I thought I would send it your way just in case. http://www.youtube.com/watch?v=8ivX-Msc7Lw

Thanks for the link man.
I had seen it but appreciate
you posting it just in case!

Do you actually trust Suunto that much ? My Vector can be as much as 25-75 feet off at any given time.

 

so what was the reading on the laser?
that would tell you exactly how much the suunto was off...

actually, the word of caution to newbies should be: don't follow people that do not laser object before first jumps :-)

btw: i have a laser good up to 1000yards, just so that i CAN laser everything. which i do...

flummi

Count on +\- 20 feet at a minimum with any pressure based alt device.

Do better research, before betting your life on a measurement.

Also, your eyes should tell you , " this seems low for 260"

+1

Altimeter watch can be off give or take 10ft(if that's the icriments),and if there is a change in barometric pressure.Also if there's a big change in temp it can throw the altimeter off.Best thing to use is laser.In my experience the antennas I have been on were right on with laser in comparison to the online site height.(that's adding the estimate for the stinger,or light pole.

Then what, you take the average? Likely only one of them is correct, or none

Ronald

seen the vid, i belive.......and wow wicked tight landing......good job!

"Peace Bitches" looks like you have six fingers on your right hand. Do you have six fingers on your right hand?

Im glad to see I m not the only one who has been dealing with this. We have a 290' A that we have been Free Falling for over a year. Maybe a combined 100 jumps total on it. we lasered it before the first jump and it matched with the web info and it "felt" like about 300. Then a few weeks ago someone brings an altimeter watch (not sure what kind). We get to the top, and the watch says 245. Then I hear "Wow cant believe we have been FF this." " I want a PCA". The watch made people that were comfortable making a dozen FFs suddenly change there mind.

Now, If someone wants a PCA, no problem. It is there jump they can do it how they want. But the watches are not that precise. They are a good estimator but I dont think they should be counted on in the range where you are trying to decide between a FF or PCA. One of these jumpers even went back in there log book and changed the height of the A on previous jumps.

...when I was strong enough, I dedicated my life to the study of fencing. So the next time we meet, I will not fail. I will go up to the six-fingered man and say, "Hello. My name is Inigo Montoya. You killed my father. Prepare to die."

My thoughts exactly!

<shakes head>
I still contend the only altitude that matters is the opening altitude. and that only has to be high enough for a manageable (i.e. within the jumper's comfort zone) landing.

Precise measurement of exit? (I guess it is a great security blanket.) I bet few have accurately measured the distance it takes their parachute to open. Why know one with great care, but not the other? The critical margin of error always lies in the poorer measurement.

Initially, jump conservatively. If experience says you can be more aggressive, cool. Experience should always count for more than a watch altimeter...

but what do I know?

I would free fall much lower than I do if I was sure to have a nice clean opening.

The internet is NEVER wrong. That Suunto must have malfunctioned.

does anyone do rock drops anymore?

Ya but I usually forget to put the rocks in my buddy's bag while he is not looking before climbing the A.

Wwarped, have you seen the video?
Does the LZ look tight to you?

Next time I go visit Neuwanda I will bring my
laser, count the rungs, and report back the
data if any one is bored/curious.

As for the distance for my canopy takes to open,
Yes, I have studied this with repeated jumps from
the same object with different PCs and deployment
methods.

I know I could be more aggressive but usually I am
good about doing it slowly. On that A I actually had
the bridle S folded in my hand, remembered I have
a good life, good wife, and money in the bank and
then decided to do the smart thing for me.

I will eventually freefall this A but after a little
more experience and with better wind conditions.

Lastly, I have the normal number of digits on each hand.

the correct number of digits on each hand... kind of like this? could you imagine playing guitar?

Very unique pics, imagine that guy doing
some bad ass flamenco guitar. I think in
the futuristic movie 5th Element they had
a concert pianist who was rocking some
extra digits also.

Wrong movie. You're thinking of Gattacca with Uma Thurman.

thats funny shit.

If you believe you need the extra altitude for a safe landing, then feel free to stick to s/l. No problem. Do what's best for you. (I might do the same.)

But remember, you are making the decision based on opening altitude (ensuring time to set up your landing), not exit altitude.

I bet no matter how many times you measure that thing, the s/l opening height won't change... (assuming consistent packing, exit, and other techniques.)

Suunto specifically state that their altitude measurement devices should not be used as the primary means of measurement whilst participating in any aviation activities.

Download Suunto Manuals Here:
http://www.suunto.com/...98&bmUID=ijKnRjr

After seeing pictures, I withdraw my +1 to FF it.

Who read the manuals? :D

V

And who said anything about using them for any aviation activities? :)

some

Counting the rungs is nice, but not all towers are the same obviously. 250 rungs at 12" is a fair bit different than 250 rungs at 13.25". Like 26 feet. Not that big of a deal if you've got the height, but it matters if you are getting low.

I count the rungs everytime we climb. I think it's some kind of disorder.

i keep an 18" piece of fabric measuring tape in my saddle bag - i also know when i rest my elbow on a rung, where on my hand 12" falls - i have same counting disorder.

I just caryy 1000' rope marked off every ten feet with a weight. Lower it to the ground see how high i am then drop it and pick it up after landing

and your always really,really high.

assuming no gail force winds too. That's why I usually take about a 500 pound weight, just in case it gets windy!

As a newbie, I really appreciate the effort you guys go through to give us knowledge

I made myself a measuring device with static line, that way if the jump is too low, like 200ft i can just cut the tape and SL off

haha, i'm always counting stairs...

As is 173 if your name is Matt.

..But only if the landing area isn't a garbage dump.

Its not a garbage dump. I found a bull carcass there. Do you call that garbage??

i'm confused.... 3 in the pink, 3 in the stink????

i was likewise wondering if that made it inherently more difficult to fist a chick? you know does the extra knuckle add alot of width?

I've got just the opposite situation going on close to my house....there's a 350 footer (as stated on the info plate at the base), yet the google earth app says it's 300'...hmmm

i really shouldn't have to say this but...

those "info plates" aren't always correct either. in case you didn't know.

I looked at a crane a while back and guessed it to be 300 feet. I wanted to confirm the height with range finder. Boy was I wrong. It was only 295!

you could have died!

On that note, there's a B I used to jump that was listed online as 450'-lasered at 350'. Still high enough to be plenty safe but still when you're planning a 2-3 sec delay . . .
Seriously this is all shit a new jumper should know even without someone telling them. If you're too stupid to confirm sketch alts and make a safe plan then why bring a rig along?

ha ha ha yeah...i think those "info" plates are to make the people who buy the towers feel good about themselves!