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Old Feb 21, 2013, 06:52 PM
Koo
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Project High Flight. Livestreaming feed to 100,000 feet on Sunday, April 21.

Hey guys, today I joined a student organization here at Miami campus called Project High Flight. They send a weather balloon up to 60-100K feet and gather data and bacteria. Well, I heard that they wanted a live video to the ground and decided to join them.
Here is the deal, I need around 40 mile range out of an FPV system. I was going to go with 1.3ghz since its a clean frequency and has awesome antennas.

The balloon has 5 GoPro Hero 2s and we are going to be getting live feed out of 1 of them.

We have all of our equipment purchased and installed, but we still have a problem using ublox-6M gps with ET. If anyone could help us with this, please PM me!

Above it All (5 min 18 sec)



Little update. The updated launch date has been moved from March 28 to April 15. Will happen around 4pm GMT - 4:00.
Another update: The launch was pushed back to next Sunday.
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Old Feb 21, 2013, 08:27 PM
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Now the question time. That's a super cheap vtx, will it have any problems and is it really 1500mw?
Being from RMRC it should produce what's on the tin. High power Vtx may cause problem with GPS reception on the balloon if it use one.


Quote:
Any criticism/feedback on the antenna choices?
Excellent choice. A Gatling would be the top dog, but still may be overkill even for sub orbital flight


Quote:
What kind of distance should I expect with this setup?
Having really clear LOS by pointing up high it should have close to 100km, Take good note that I don't make for any noise.

-Hugo
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Old Feb 21, 2013, 09:19 PM
Koo
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Thanks a lot. I thought about using the gatlin for this, but the $400 price seems kind of unjustified for an antenna. Also, I'm kind of confused what good a SAW filter does. To my understanding, its good to have if I fly with multiple people using a frequency close to the one I'm receiving. Does the SAW filter improve the range even if there is no one else transmitting on the frequency?

Oh another question, would a high pass filter prevent any interference with a GPS?
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Old Feb 21, 2013, 09:34 PM
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Does the SAW filter improve the range even if there is no one else transmitting on the frequency?
Yes, it add a little sensibility to the rx, some benefit more than others.

400$ is indeed steep for tracking a balloon, but not for a 30K UAV, which where most are used. The pepperbox should make you reach your goal.

-Hugo
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Old Feb 21, 2013, 09:35 PM
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Since you'll be using a high gain antenna pointed essentially straight up, why not use 2.4ghz? It won't interfere with your GPS, the antennas are much smaller (about half the size of the 1.3ghz antennas).

You don't need to worry about a SAW filter. It stands for Surface Acoustic Wave filter. It is a narrow band filter, used to increase Vrx sensitivity. But in your application, you don't need to worry about it. The stock Vrx works amazing.
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Old Feb 21, 2013, 10:16 PM
Koo
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The size of the antennas is almost irrelevant in our use. We do, however have a GPS tracking device so I'm not completely sure how its going to be effected by the vtx. Would a high pass filter be enough to reduce any chance of interference?
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Old Feb 21, 2013, 11:35 PM
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Originally Posted by Hugeone View Post
Excellent choice. A Gatling would be the top dog, but still may be overkill even for sub orbital flight
-Hugo
I don't know, Hugo. With tx antenna orientation being a problem on altitude attempts (regarding the null of the antenna), your Gatling might be required for this mission. It's a real killer antenna. Nothing compares to it.

@Koo - I highly suggest you consider the Gatling. It is better than the Pepperbox for this mission.

-Alex
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Old Feb 21, 2013, 11:41 PM
fly by night
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can find the list of known FPV records here: http://fpvlab.com/forums/showthread....-(LEADERBOARDS)

fixed wing record is 23,000 ft.
balloon s 35,000ft on the list

But I remember some kids with DragonOSD and a balloon went to 80,k ft , IIRC
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Old Feb 21, 2013, 11:46 PM
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i'm going to follow this thread with particular interest since i just got signed up to help the local high school high altitude balloon project
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Old Feb 22, 2013, 03:46 AM
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Those high frequency bands are poor choices for range, and your legal output power is pretty limited. I'm not aware that 1.3g is a legal frequency to transmit on here in the US anyways.

I suggest getting a technician class FCC license (easy), and transmitting at 433mhz on the ATV band. The lower frequency will carry much further and you can put out as much power as I would reasonably imagine you could supply from a balloon battery.

As an added bonus everyone in your area could put their TVs into "cable" mode with a regular TV antenna attached and see your video. The only real limitation I know of is that you have to display your callsign every 10 minutes (use OSD or letters in view of the camera).

PM me if you want a link to a cheap 4-5W system I found.
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Old Feb 22, 2013, 05:12 AM
I Like Clouds Made Of Limes?
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Sounds like a good project!
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Old Feb 22, 2013, 07:24 AM
I tell her RC is cheap !
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Sub ! I want to see that video Good luck on the project
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Old Feb 22, 2013, 08:00 AM
I Like Clouds Made Of Limes?
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The way that balloon just popped and just, well stuck around was awesome!
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Old Feb 22, 2013, 08:53 AM
Koo
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United States, OH, Oxford
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Originally Posted by IBCrazy View Post
I don't know, Hugo. With tx antenna orientation being a problem on altitude attempts (regarding the null of the antenna), your Gatling might be required for this mission. It's a real killer antenna. Nothing compares to it.

@Koo - I highly suggest you consider the Gatling. It is better than the Pepperbox for this mission.

-Alex
I will keep that in mind. They weren't even supposed to have the video gear in the balloon for the next launch, so this launch is kind of like an experiment for the video system. If the pepperbox doesn't work well enough, we can always buy the gatlin later.
I recall seeing a video of a 100km flight with a 10dbi helical, so I'm pretty optimistic.

Quote:
Originally Posted by jakestew View Post
Those high frequency bands are poor choices for range, and your legal output power is pretty limited. I'm not aware that 1.3g is a legal frequency to transmit on here in the US anyways.

I suggest getting a technician class FCC license (easy), and transmitting at 433mhz on the ATV band. The lower frequency will carry much further and you can put out as much power as I would reasonably imagine you could supply from a balloon battery.

As an added bonus everyone in your area could put their TVs into "cable" mode with a regular TV antenna attached and see your video. The only real limitation I know of is that you have to display your callsign every 10 minutes (use OSD or letters in view of the camera).

PM me if you want a link to a cheap 4-5W system I found.
We have couple people in the team who have the technician license. I haven't had any experience transmitting at a low frequency like that and I imagine that getting CP antennas would be a pain in the butt as well.
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Last edited by Koo; Feb 22, 2013 at 08:59 AM.
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Old Feb 22, 2013, 10:08 AM
Project Tormentor is flying!
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I'm not convinced that you need to go CP for this application. Your antenna on the balloon shouldn't be changing it's orientation very much during the entire flight.

I'm almost inclined to think that a V and the Vtx and a high gain yagi would work very well...but I defer to what Alex and Hugo suggest. THEY are antenna developers and as such know FAR more than me in this area.
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