I know that since ASTRO-1 and ASTRO-2 have proven we can find what we launch, people have suggested wnd speed meters, Geiger counters, ATV systems, gliders, rovers, wireless access points, etc. be deployed on the balloons.
How about something simple like an HF beacon? This can operate at milliwatt levels (part 15) and can be received by many many many old-time hams. A suggested frequency - 10m because there are a lot of 10m Yagi beams in the world.
This would be an excercise in propagation and QRP operation. The antenna could be a half-wave of magnet wire, or an end-fed Zep.
I talked it over with Dan (KD5NJS) at lunch and he though Maxim had some one-wire or dip-switch programmable oscillators that could drive a buffer chain of NOT gates, then out to the antenna.
Proof of concept: I'll start looking for HF Air Traffic Control transmissions (likely Houston or Miami) at my QTH. That will give us an idea of how much power, etc. will be needed as well as a baseline for equipment. I have a pocket SW reciever (Grundig Mini200) a couple portables (DX-440s) an Icom IC-706MKIIg and perhaps a Grundig Satellite 900 down the road.
Just an idea.
73
Scott
Showing posts with label balloons. Show all posts
Showing posts with label balloons. Show all posts
Tuesday, February 15, 2005
Thursday, February 10, 2005
Experiment on Heat Reflection
After seeing all the different payload boxes on the ASTRO-2 flight, I though to myself, "what is the best way to do this" and how I determine that in a way that
1) would involve simple tools found in the kitchen, hobby room and Radio Shack
2) would be easily verifiable and repeatable
3) would stimulate some thought, discussion, and maybe some lightweight math and physics.
4) eventually a computer model could be established to simulate the cabin and outside environments on a future balloon payload.
S0, I picked two "automotive" indoor / outdoor thermometers from Radio Shack for not a lot of change. These make nifty low DC voltmeters too. So I had 4 channels of thermometer.
1) CH1 (a remote probe) for in the test chamber (a.k.a. balloon payload)
2) CH2 (another remote probe) for the area between the test chamber and the desk lamp (a.k.a. "the atmosphere")
3) CH3 (built in) was in the back of the bench and was to measure ambient temp away from the lamp.
4) CH4 (built in) was the same thing, but on the other thermometer. There might be a way to remove some experimental error taking these readings into account.
The next thing was to find a sample balloon payload enclosure. I didn't care what it was made of at first, because I wanted to just test out the theories and equipment. I did know I wanted something of a uniform contruction. I had on-hand:
1) some plastic cups without lids
2) a ceramic coffee mug
3) a plastic tumbler
4) a styrofoam cup
5) a stainless steel insulated mug (a freebie from work)
but either these didn't have a lid, or the lid was made of a different material. I thought that would undermine the integrity of the experiment. So I settled on a glass jar with glass lid. (I'll photograph and weight it out later)
I needed someting inside the "capsule" to heat up. So I filled it up with styrofoam packing peanuts leftover, by this point, from Christmas. This project got delayed a number of times.
So first, I thought I would investigate coatings, then move on to the actual structural material later. I thought if my readings of the instruments were good and the instruments and procedure was good, that I could determine which materials would be desirable for reflecting and absorbing heat. It's good to absorb some heat to keep transmitters on frequency (namely, its the crystal that needs to be kept at temp) but it's also good to reflect away heat that would otherwise kill a biological sample, or trouble other electronics.
I decided to start simple and work with black construction paper, some Hewlett-Packard photo paper intended for an inkjet printer, and some aluminum foil from the kitchen.
I expected to see the black construction paper absorb heat, raising the internal temp quickly while slowly releasing it when the lamp was shut off. This would be handy for parts of the payload in indirect sunlight. I expected to see the aluminum foil reflect heat and keep the inside very cool. I assumed this would be a good coating for parts of the payload in direct sunlight and it would serve as a ground plane for monopole "whip" antennas. The photo paper should have been a happy medium on the reflectivity scale. If I was really crafty, I think this could be folded (orgami ?) into ribs and spars. Then a coating of aluminum foil could be applied.
Someone could fashion a greenhouse by lining a box-shape with aluminum foil, then covering the top with Saran wrap to let in the light... The heat absorbed during the initial ascent could be saved for later (colder ) parts of the flight.
Anyway, over time I found a few spare hours to sit with clip board and stop watch. I keyed the figures into Excel. How I need to learn to publish graphs on the blog.
73
Scott
1) would involve simple tools found in the kitchen, hobby room and Radio Shack
2) would be easily verifiable and repeatable
3) would stimulate some thought, discussion, and maybe some lightweight math and physics.
4) eventually a computer model could be established to simulate the cabin and outside environments on a future balloon payload.
S0, I picked two "automotive" indoor / outdoor thermometers from Radio Shack for not a lot of change. These make nifty low DC voltmeters too. So I had 4 channels of thermometer.
1) CH1 (a remote probe) for in the test chamber (a.k.a. balloon payload)
2) CH2 (another remote probe) for the area between the test chamber and the desk lamp (a.k.a. "the atmosphere")
3) CH3 (built in) was in the back of the bench and was to measure ambient temp away from the lamp.
4) CH4 (built in) was the same thing, but on the other thermometer. There might be a way to remove some experimental error taking these readings into account.
The next thing was to find a sample balloon payload enclosure. I didn't care what it was made of at first, because I wanted to just test out the theories and equipment. I did know I wanted something of a uniform contruction. I had on-hand:
1) some plastic cups without lids
2) a ceramic coffee mug
3) a plastic tumbler
4) a styrofoam cup
5) a stainless steel insulated mug (a freebie from work)
but either these didn't have a lid, or the lid was made of a different material. I thought that would undermine the integrity of the experiment. So I settled on a glass jar with glass lid. (I'll photograph and weight it out later)
I needed someting inside the "capsule" to heat up. So I filled it up with styrofoam packing peanuts leftover, by this point, from Christmas. This project got delayed a number of times.
So first, I thought I would investigate coatings, then move on to the actual structural material later. I thought if my readings of the instruments were good and the instruments and procedure was good, that I could determine which materials would be desirable for reflecting and absorbing heat. It's good to absorb some heat to keep transmitters on frequency (namely, its the crystal that needs to be kept at temp) but it's also good to reflect away heat that would otherwise kill a biological sample, or trouble other electronics.
I decided to start simple and work with black construction paper, some Hewlett-Packard photo paper intended for an inkjet printer, and some aluminum foil from the kitchen.
I expected to see the black construction paper absorb heat, raising the internal temp quickly while slowly releasing it when the lamp was shut off. This would be handy for parts of the payload in indirect sunlight. I expected to see the aluminum foil reflect heat and keep the inside very cool. I assumed this would be a good coating for parts of the payload in direct sunlight and it would serve as a ground plane for monopole "whip" antennas. The photo paper should have been a happy medium on the reflectivity scale. If I was really crafty, I think this could be folded (orgami ?) into ribs and spars. Then a coating of aluminum foil could be applied.
Someone could fashion a greenhouse by lining a box-shape with aluminum foil, then covering the top with Saran wrap to let in the light... The heat absorbed during the initial ascent could be saved for later (colder ) parts of the flight.
Anyway, over time I found a few spare hours to sit with clip board and stop watch. I keyed the figures into Excel. How I need to learn to publish graphs on the blog.
73
Scott
Tuesday, February 08, 2005
February Broken Arrow Amateur Radio Club meeting
Last year, after some arm twisting, I accepted a change in position from secretary to president in the BAAARC. One concern was "quality programs." So I asked Harry (KC5TRB) to come out and talk to us last night about his informal (anyone can join) Oklahoma Research Balloons group. Rich (KD5JXU) came to help. They showed off the various ways (easy, hard, simple, powerful) to deploy a APRS station and access the "Ham internet."
The also talked about the history of their club (about 15 launches), and the balloon internals. Very interesting use of small computer (Palm III class gear and pencams) and Ham rigs.
I had starting playing around with graphing temperatures in and around chambers of different construction methods and colors. I'll wrap the experiment up, graph the points and write about it soon. I'd like to fly my own payload at some point.
I bought a Mac Mini today. Hoping to have a "QRP" computer.
Also in the hopper at radio station KD5NJR, a Telpac station to provide Broken Arrow with low speed Internet email via the Winlink 2000 suite.
W5GGW is writing tiny clients for Winlink, Echolink and APRS in Java. In theory that would port to almost any device.
Nikropht asked me some crazy thing about magnetic fields while I was freezing in the parking garage. Wonder what that is all about.
More later.
73
Scott
The also talked about the history of their club (about 15 launches), and the balloon internals. Very interesting use of small computer (Palm III class gear and pencams) and Ham rigs.
I had starting playing around with graphing temperatures in and around chambers of different construction methods and colors. I'll wrap the experiment up, graph the points and write about it soon. I'd like to fly my own payload at some point.
I bought a Mac Mini today. Hoping to have a "QRP" computer.
Also in the hopper at radio station KD5NJR, a Telpac station to provide Broken Arrow with low speed Internet email via the Winlink 2000 suite.
W5GGW is writing tiny clients for Winlink, Echolink and APRS in Java. In theory that would port to almost any device.
Nikropht asked me some crazy thing about magnetic fields while I was freezing in the parking garage. Wonder what that is all about.
More later.
73
Scott
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