November 14th 04, 04:08 AM
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MassachutsusWilliam wrote:
(Len Over 21) wrote in message ...
In article , Mike Coslo
writes:
Brian Kelly wrote:
Mike Coslo wrote in message
...
KØHB wrote:
"Mike Coslo" wrote
Twist? A large part of your post was quoting:
The quotes (of the FCC officials) were selected to point out what the
regulators seem to be expecting of us.
I'll assume that you believe what you posted? (correct me if I'm
wrong)
Yes, I believe that is what those regulators said.
I would hope you would set a good example by taking the lead.
I did take the lead, by trying to point out what seems to be the
prevailing regulatory attitude towards us. I further took the lead by
pointing out that I feel the ARRL ought to shift some of the 'political'
spending into programs which sponsor and nuture an attitude of tinkering
and experimenting among amateurs.
I've posted a project I'm getting started that will go a long way
toward making us look good and helpful and relevant.
Wanna help?
Maybe I'll bite. What's up?
A near space Science project, such as I outlined to Jim, is a great way
for Hams to get involved in a whole lot of fun, and a bit of work, but
that can be fun too.
Essentially we are building and launching "almost satellites". This is
a balloon launched payload that heads to around 100,000 feet or so,
conducting experiments for the duration.
Have you looked at Federal Air Regulations in regard to such
high altitudes? This isn't like hot-air ballooning at low altitudes
where manned free balloons have rights of way over all others.
They need a way to burst the balloon on command (i.e., nichrome wire
wrapped around the balloon plug, a receiver, and a battery),
metallized RADAR reflectors on the instrument chain, and FAA clearance
to launch.
Much of this depends on the size of the payload.
There are other, much more often used methods to burst the balloon at
the desired altitude.
Back in the 60s the weather folks used to loft a quarter million or
so weather balloons per year...with little transmitters in them and
telemetry done with extremely low-cost electronics. Good example
of doing things simply and for low cost per launch.
They still do. It is called a rawindsonde and the rawin observations
are transmitted over the weather networks and shared worldwide.
Multiple launches every day right in my neighborhood.
These
ballons often reach 10MB, but the payload is much smaller than most
EOS amateur projects.
6 pounds is the magic number for the FAA. NOt a problem for one of
those latex balloons.
The experiments can be just
about anything you can think of that can be done at that altitude. Most
launches are multi-mission, with both science and Ham fun stuff on
board. And of course the Ham fun can be scientific too.
Hams have had fun ballooning for quite a while, but the advent of
inexpensive GPS has changed things dramatically. We now fully expect to
get our payloads back! That wasn't the case not too many years ago.
The balloon is usually one of the latex weather balloon variety. Zero
pressure balloons can be used too, but since they are designed to go up
and stay up for a long time, that would be a more complex proposition.
You need to do some math on that before envisioning such a "low-
cost" approach to get to 100 Kilofeet. Those 8-foot (typical)
"weather balloons" aren't going to get up that high, not even a mass
of them.
You need to consult some (free for the asking) density values of
the atmosphere and some back-of-the-envelope figuring first. Note
that you have to allow for the lifting gas expansion with altitude. It
is far from the same at 100 kilofeet versus sea level.
Lots of expansion.
around 30 feet in diameter at burst!
The payload uses Amateur radio for command and control. At the heart of
the system is a GPS unit in conjunction with a packet radio. The
telemetry data is sent back to earth and kept track of with a computer.
The computer lets us know where the payload is, where it is going and
how fast, and predicts the landing site. Oh, and it's freeware.
That's going to be a minor cost item. As you will find out, the
balloon structure, its support infrastructure, and lifting gas will
cost more than you think..
It all adds up. Might be good idea to get a sponsor.
In addition, the packet radio can send back other info as the mission
may desire. The mission is often controlled by a microprocessor. To
date, a lot of balloonatics use basic stamp controllers.
Often a repeater is put on board. A small one has a lot of coverage at
100,000 feet! There is usually a VHF beacon, and occasionally a 10 meter
beacon also, although that is not as prevalent as it was before GPS.
Two words: Payload weight.
You can't get up in the blue sky with lack-of-detail blue sky ideas.
If it were that easy, lots and lots of folks would have done so a
half century ago.
And all of those gps, beacons, packets, thermistors, pressure
transducers, and video cameras and ATV transmitters operate off of
heavy batteries. Luckily the ascent and descent won't be that long,
and the batteries can be scaled back from what is normally required
with one caveat. You'll want the beacon to be operable for several
days, if possible.
The experiments vary. One of the favorite devices for the grade and
middle school kids is something called a pongsat. This is an experiment
that can be anything that will fit inside a ping-pong ball. Sounds
weird, but there are plenty of small scale experiments that fit the
bill... er, ping-pong ball.
The balloon lifts the payload to the predetermined altitude, and
bursts. The payload drops, and the Ham comms can continue during
descent, although the first few moments after burst can be pretty weird
as the payload often does some pretty strange gyrations until the
parachute can grab some atmosphere. Drops like the proverbial rock.
All this time, the GPS is keeping track of the whereabouts of the
payload.
Commercial grade GPS recievers are designed to not work above 60,000
feet. Crazy precaution against strapping one to a missile and using
it as a guidance system.
There are ones that operate above that altitude.
Then at landing, it turns into a foxhunt as the hams use the
beacon transmissions to find the payload. With the advent of us getting
used to the software and the precision with which the GPS can determine
the location, it is not too uncommon for the recovery team to witness
the landing.
Launch of one of these things does not take as much bureaucratic red
tape as most people think.
You've done that? You are going to the edge of the stratosphere and
think you can do so freely? Ain't quite that easy.
And it can be done for surprisingly little money.
"Surprisingly little" is a highly subjective term. Real projects have
quite objective, finite budgets.
The people that are needed are of course Hams, and people with some
programming experience. People with experience building things, and a
meteorologist can't hurt! People that don't mind a drive on a weekend
day to serve on the recovery team. Plenty of subteams, such as payload,
publicity, science, visualization, integration, education liaison. Even
people that might just want to feed all the other reprobates.
Sounds like you've already filled the "executive" position. :-)
This is real stuff. This might spark the interest in science in some
youngster. And that is not only a career choice, but a service to the
country. American scientists are becoming pretty rare.
"Becoming pretty rare?" Not quite as any visit to academia will
show but feel free to get opinionated.
Its great publicity for Amateur radio.
It will get ham radio noticed, but what is written up by journalists
may not be what you expect.
Free ballooning has been going in the USA since 9 January 1793,
the first American flight by Frenchman Jean-Pierre Blanchard,
lifting off from the Walnut Street Prison in colonial Philadelphia.
That was witnessed by none other than President Washington.
[from "Lighter Than Air Flight" by Lt. Col. C. V. Glines, USAF,
Franklin Watts Inc., NYC, 1965, data from pp 29-35] That's over
two centuries of time...
And we can innovate and experiment. Radio is a pretty mature science
now. It's doubtful that any of us are going to invent a grand new
communication scheme, or an antenna that does DC to daylight, or even
one that is a whole lot better than what we have now. So What we need to
do is to integrate what we have now, and do some innovation with it. We
also need (or at least should) prove our worth to the community.
That we can do it while having fun is a real bonus.
You can have all your innovative fun doing many, many things.
Until you find out what helium costs to lift the total balloon (the
balloon itself, its payload, its carrying structure, its all going to
be a pipe dream having no more basis than enthusiasm.
Check out the prices for helium with a gas supplier, plus what it
takes to haul to HEAVY gas cylinders to a launch area, plus the
metering system plus the filling system plus whatever else. All
that after you've investigated what the actual lifting capacity will
be in terms of ounces per cubic feet of balloon. [I said ounces,
not pounds...lighter than air does not mean negative weight]
You could get "efficiency" by going for hydrogen gas...which is
offset by very direct DANGER from many and varied sources.
Yikes! If they use the nichrome wire on the balloon plug trick...
Somone asked about that. I don't know the exact results. Hydrogen has
to mix with air to be explosive. The pure stuff would burn with a red
flame in a "pop" sot of mode. I'm not planning on using plain old H tho'.
Still going for 100,000 foot altitude? Start thinking in terms of
the balloon exapanding to something on the order of EIGHT times
in size at altitude maximum. That's visible on some of the high
altitude research balloon flights of the 1960s using lots and lots
of plastic sheet for balloon material.
Your project may need a virgin...such as Richard Branson...to
help start it off.
Now, if you are REALLY thinking about this whole thing, look into
"Project STAR" and a little thing like a model airplane that crossed
the Atlantic (from Newfoundland to the Irish coast) during the 38
hours in August 9, 10, and 11, 2003. Laugh all you want but a few
guys from around DC managed to do that through GPS guidance
on board as an autopilot. You can read about it at
http://tam.plannet21.com/index.htm
Pictures and stuff to guide you even if you are not into model flying.
38 hours (approx) of powered flight using only 5.5 pounds of fuel,
flight path of 1882 miles. Radio control only for take off and climb-
out, then landing in Ireland...the rest entirely on "autopilot." It had
some means of reporting its position to earth via satellites. That
alone would be of interest to anything else involving GPS location
or guidance.
Search around on the huge NASA website for atmospheric info,
especially for density versus height. You could do an approximate
curve of payload + balloon weight versus cost of helium in hundreds
of cubic feet to whatever altitude limit. That will give you some
realistic viewing into feasibility of it all.
Sounds like fun. Dense air operations in the eastern states may pose
a big problem.
Should be a lot of fun. I would note that there are some of these
projects going on in Mass. They do it. Although I did see one of their
BalloonTrack screens showing a ocean landing east of Cape C
- Mike KB3EIA -od!
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