Launch status – flight ready
Launch date – TBD (but soon!)
For the second launch we plan on capitalizing on our success while addressing our failures. Looking back at our last launch, the failure of the Spot messenger was not catastrophic, but could have been. I still feel it is important to have a backup gps in case of a failure of the 2M transponder. The failure of the Spot to send messages was felt secondary to destructive interference from the 5watt 2M transponder. So the goal for this launch, in addition to the previous flight goals, is to track the payload once on the ground using the spot messenger. After a lot of thought and research, it was clear we needed a new antenna.
The previous fight, Virgin HABlantic-1, used a rubber duck antenna coming out of the side of the payload. While effective, it did not have a lot of gain and created a lot of Rf above the payload where the spot was mounted. We needed to come up with an antenna that would propagate a signal more downward, and attempt to create a radio null above the payload. Was considering a “baseloaded” antenna that would be mounted on the bottom of the payload, but if not tuned perfectly you can get a lot of Rf coming back. I give the credit to Jack Fanning for coming up with an elegant solution… he proposed that we go with a j-pole antenna made out of simple twin-lead line. J-poles, also called Zepps, were invented by the Germans for use on their Zeppelin airships, or balloons. How cool is that!! Jack built the antenna, tuned it, and tested it. The improved gain with this design will allow us to run a much lower wattage on the transponder output.
While the 2M gps transponder has a lot of cool settings, it seemed hard to use the programming to simply lower the output wattage. By lowering the voltage provided to the power amplifier, we were able to lower the output wattage to about 1.25 watts. I achieved this simply by eliminating 2 of 6 batteries (3V). I am still working on an easier fix for this.
I did test the j-pole running on a lower wattage in close proximity to the spot running and was able to get good data from both devices. The test did have its limitations, but I am feeling more confident now that both devices will work in harmony…. but only time will tell.
At this time, we are flight ready, and waiting for better weather conditions on one of these late fall weekends.
Supplies for Virgin HABlantic-2
- 1 – Canon A330IS camera with high capacity Li-ion battery
- 1 –Canon A4000IS camera with high capacity Li-Ion battery
- GoPro Hero 3+ black with water tight case and drying packets
- GoPro battery extender
- 2M GPS transmitter (Big Red Bee) with twin-lead J-Pole antenna
- Li-Ion AA batteries
- Spot Personal Tracker
- 1200g HAB Kaymont Balloon
- 200 cuF Helium tank
- 3 cm weather balloon inflator/regulator (High Altitude Sciences)
- Velcro strips
- Hot hands warming packets
- Latex gloves
- Rubber bands
- Duct tape
- 4’ Rocketman parachute
- Electrical tape
- Mylar blanket
- Assorted wood pieces, eyebolts, epoxy glue
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