High Desert Rocketry
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- Mar 21, 2011
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Last week a friend of mine asked if I could help with the launch and recovery of a HAB. I called another friend of mine doing the Sugar Shot to Space project with me and asked if he was available so we could test the EggFinder we have been using in our small scale 75mm Sugar Shot sustainer. It has continued to transmit gps up to our 30,000' flights and this would be a great opportunity to test just how high up we could still receive the signal.
Both the transmitter and receiver have the optional 2-3 db gain antennas on them. Because we were going as a 'ride-a-long' payload we would have to keep our weight below 79 grams. While the stock EggFinder weighs in at under 20 grams, the 2s Lipo battery and the optional antenna would add additional weight and that didn't include the insulating styrofoam 'brick' I needed to fashion for thermal protection and the string used to hang it below the primary scientific payload that was being launched.
The balloon was prepped pre-dawn for an early launch from a parking lot in the Southern California desert city of El Centro. Normally I've flown HABs using APRS/GPS but on this we would be using the EggFinder LCD Receiver with Bluetooth to track our our cell phone. The balloon had been in the air for over an hour when shortly above 80,000' we lost contact as the balloon was directly high above us. We continued visually watching the balloon from that location until we saw it burst at around 100,000'...you actually just see the small white dot in the sky vanish.
Sometime later we began receiving the signal at about 60,000' as it slowly came down on parachute. We continued monitoring as we drove below its position until somewhere around 5,000' we visually spotted the chute and watched it land a few hundred feet away in an alfalfa field.
Possible reasons for losing contact at 80,000':
1) We had been using Rocket Locator and were directly under the balloon when we lost contact...the antenna were now vertically aligned.
2) Even though I put the EggFinder in a styrofoam 'brick', it had been up in the subzero temperatures for over an hour.
3) At 80,000', it was too high up for the 3db gain antenna
and maybe
4) To save weight, we used our smallest 2s lipo battery we had since we were doing a ride along with a much larger experimental payload.
I believe if we were using a panel antenna and not directly below the EggFinder we could have tracked it all the way to 100,000'.
Rick
Photos: Prep, High above Salton Sea, Chris trying to regain reception at 80,000', me holding the red styrofoam 'brick'
Both the transmitter and receiver have the optional 2-3 db gain antennas on them. Because we were going as a 'ride-a-long' payload we would have to keep our weight below 79 grams. While the stock EggFinder weighs in at under 20 grams, the 2s Lipo battery and the optional antenna would add additional weight and that didn't include the insulating styrofoam 'brick' I needed to fashion for thermal protection and the string used to hang it below the primary scientific payload that was being launched.
The balloon was prepped pre-dawn for an early launch from a parking lot in the Southern California desert city of El Centro. Normally I've flown HABs using APRS/GPS but on this we would be using the EggFinder LCD Receiver with Bluetooth to track our our cell phone. The balloon had been in the air for over an hour when shortly above 80,000' we lost contact as the balloon was directly high above us. We continued visually watching the balloon from that location until we saw it burst at around 100,000'...you actually just see the small white dot in the sky vanish.
Sometime later we began receiving the signal at about 60,000' as it slowly came down on parachute. We continued monitoring as we drove below its position until somewhere around 5,000' we visually spotted the chute and watched it land a few hundred feet away in an alfalfa field.
Possible reasons for losing contact at 80,000':
1) We had been using Rocket Locator and were directly under the balloon when we lost contact...the antenna were now vertically aligned.
2) Even though I put the EggFinder in a styrofoam 'brick', it had been up in the subzero temperatures for over an hour.
3) At 80,000', it was too high up for the 3db gain antenna
and maybe
4) To save weight, we used our smallest 2s lipo battery we had since we were doing a ride along with a much larger experimental payload.
I believe if we were using a panel antenna and not directly below the EggFinder we could have tracked it all the way to 100,000'.
Rick
Photos: Prep, High above Salton Sea, Chris trying to regain reception at 80,000', me holding the red styrofoam 'brick'