HSMM and balloons
doug.gentges at gmail.com
Sat Oct 20 21:49:57 CDT 2012
Here in Denver, our local high altitude balloon group EOSS was paying over
$300 for a He 300 ( about 260 SCF) until mid summer, when we were told it
was no longer available at any price. We're now paying $18 for a similar
sized bottle of H2.
It does wonders for the budget, although we have a small number of members
who want nothing to do with H2. We call that the Hindenburg effect.
I saw that the Red Bull jump needed 180,000 SCF of He for their fill.
On Oct 20, 2012 7:38 PM, "Robert E. Seastrom" <rs at seastrom.com> wrote:
> Louis Mamakos <louie at transsys.com> writes:
> > Not if you're using 802.11 Wi-Fi radios at 2.4GHz.
> > http://en.wikipedia.org/wiki/Hidden_node_problem
> Hidden node doesn't mean it won't work; it just won't work well. When
> people suggest playing with mesh networks for moving any non-trivial
> amount of data, I go with the assumption that they already discarded
> the notion that they will work "well" long ago. Remember that 1200
> baud packet suffers from the hidden node problem too, yet somehow it
> manages to "work".
> I think the number for pure-Aloha mode throughput is 18.4% of
> available channel bandwidth.
> On a related note, I buy helium periodically (in 60 cubic foot "owner
> tanks" - $78.87 each for the fill last time I picked one up). Helium
> is in short supply and expensive like whoa these days, to the extent
> that grocery stores are not handing out free balloons to kids anymore.
> Had a conversation with the guys at Arcet a while back. One can get
> (4 9s pure grade which is the cheapest stuff they've got) hydrogen for
> a fraction of the cost (4x volume tank for same price plus rental;
> they don't do owner tanks for H2), but for some reason they're weird
> about selling hydrogen to the general public. Maybe someone read up
> on the H-Bomb and didn't realize they're selling the wrong isotope or
> that you need a little nuke to light it off. But I digress. Kind of
> ironic considering that they sell acetylene which is some fairly nasty
> stuff to all sorts of dodgy characters with no questions asked.
> So, if AMRAD gets at all interested in doing balloon stuff let me know
> and I'll see what I can do about filling out the paperwork and talking
> to anyone who calls from ATF and wants to know what's going down. I
> even have a place to store the tanks where I don't think they
> represent a hazard to anyone.
> > On Oct 20, 2012, at 4:47 PM, Martin <dcmk1mr2 at gmail.com> wrote:
> >> There was talk over tacos today of using a balloon to get a mesh
> >> router to some altitude.
> >> Federal and local regulations apply to balloon operations. There is
> >> FAR 101 that limits moored balloon operations to an altitude of 500 ft
> >> with many restrictions. A FAA NOTAM issued in 2009 forbids moored
> >> balloon operations within the DC FRZ. I believe these restrictions
> >> can be violated with a waiver from the FAA and coordination with local
> >> ATC. A local business routinely gets waivers to fly a large balloon
> >> in the area for photographic purposes (http://www.airphotoslive.com/).
> >> Chloroprene rubber balloons are used for advertising and such. They
> >> will outlast a plain latex balloon and should last several days if
> >> needed. They go for about $30. A WRT54GL runs for about four hours
> >> on a set of eight "AA" NiCads. A WRT54GL weighs about 14 oz and the
> >> batteries weigh about 8 oz. That takes a 5' balloon and about 40
> >> cu-ft of He.
> >> It sounds like a fun experiment in the right setting.
> >> Martin
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