Transmitting video via radio wave from weather balloon

[masterjoda]

My friend and I had an idea to put camera on the weather balloon and we wanted to have like a live picture from camera. But because we don't know so much about electronics we don't know how to do it. Fe figured out that we can do it via radio waves, maybe there is some more efficient way. That balloon will be flying at the 30km.

 

[berkeman]

Here's a thread from a while back with lots of good info on DIY weather balloon projects and cameras. There are lots of things to think about!

https://www.physicsforums.com/showthread.php?t=437146

.

 

[masterjoda]

Yeah but they don't really talk about that radio transmitting thing. They talk more about helium and filling the balloon that I knew already.

 

[berkeman]

Yeah but they don't really talk about that radio transmitting thing. They talk more about helium and filling the balloon that I knew already.

Actually, chemisttree's post does address the radio transmitter:

Da rules.

If you are going to use radio for telemetry, you need to stay in the amateur band which requires at least a basic license. You can use GPS with cell phone without any special license but you need cell coverage over the landing zone. You probably won't be in cell range above 5000 feet. FAA requires that you have a payload of less than 6lb for unmanned balloons. Here is a graph of the temperatures your payload will experience. If you use handwarmers, remember they will stop working where the air is thin! You should be OK for the ascent since the air in the payload is expanding and forcing, or keeping at bay, the cold air outside. Descent sucks... that cold air into your package! That's when things get iffy. It seems to me that you could put your electronics into a plastic enclosure with a one way valve like they use for coffee. You'll probably need coffee as well so you can pick up that plastic bag with one-way valve at the grocery. You can calculate an estimate for your balloon's flight plan here. http://sua.faa.gov/sua/special.do?selected=2&sua=conus both on ascent and decent. If you are near any airbases, review their "MOA" (good Google term).

How will you know how much helium to add to your balloon? Add too little and it may not pop until it drifts waaaay downrange. Add too much and it comes down too early.
Hmmmm.

It looks like you need to use amateur (HAM) radio for the communication, unless you are going to just fly the balloon low enough where a cell phone can be used. Be sure to click on the "da rules" link in his post to be sure you understand the various rules and regulations that you need to comply with. Here is a wikipedia page that discusses the radio aspects as well:

http://en.wikipedia.org/wiki/Amateur_Radio_High_Altitude_Ballooning

The easiest way to get your HAM radio license is at a local 1-day "HAM Cram" class like this one:

www.baears.com

You can search for HAM Cram classes in your area via Google.

 

[berkeman]

Another option that wouldn't require you to get your HAM Technician's license would be to just put a GoPro camera in the payload:

http://gopro.com/hd-hero-cameras/

You wouldn't get a live feed, but as long as you can find the payload package after it parachutes back to earth, you'd have your video...

 

[gnurf]

My friend and I had an idea to put camera on the weather balloon and we wanted to have like a live picture from camera. But because we don't know so much about electronics we don't know how to do it. Fe figured out that we can do it via radio waves, maybe there is some more efficient way. That balloon will be flying at the 30km.

I don't want to discourage you, but based on what you say here, I think you'll have more than enough to think about without complicating matters with a live video link. Do the recording off-line and keep it as simple as possible. What's up there that merits a (grainy?) live video feed anyway? I might be aiming too low, but if you have no prior experience you should, imo, be happy if you get a simple beacon to work. Throw in some temperature or pressure measurements when you get confident and take it from there.

 

[masterjoda]

Thanks for posts, but our project is to make live video so we can directly watch what is happening up there. Because we planed to make our balloon fly at certain altitude, and it is going to stay up there for some time so we wanted live. It is going to some kind of engine that use to "fly" to say so.

 

[berkeman]

Thanks for posts, but our project is to make live video so we can directly watch what is happening up there. Because we planed to make our balloon fly at certain altitude, and it is going to stay up there for some time so we wanted live. It is going to some kind of engine that use to "fly" to say so.

So then you have your answer. To do it legally, you need to have at least one member of your project team get their HAM Technician license, and you need to use HAM radio to downlink the video (I think it's called "slow scan" video when you use HAM radio to transmit video, but I'm not involved in that very much).

Alternatively, if you have an airplane pilot on your team, you might be able to get away with FRS or GMRS radio for the transmission, if the plane can stay close enough to the transmitter to pick up the transmissions.

The only other way I can think of is to have a much more complicated payload with a gyro stabilized platform, that uses 2.4GHz ISM band transmissions and a high-gain Yagi TX antenna that stays pointed at your mobile receiving platform on the ground (a chase vehicle).

 

[masterjoda]

I think that in my country you don't need license but i'll check, this with pointed antenna can be little tricky, maybe this radio will be better for beginning, thanks.