NSL-28

Sharron Harris steam plume geysering above the low clouds

View from the top

Somewhat visible: Albemarle Sound, Lake Phelps, the Pungo and Pamlico Rivers

Ever popular burst image

The chase crew waiting during descent

APRS reception plot courtesy of Ray KC4VTX

The floppy antenna

See stills from video 15mins apart above.
Paul previously noticed that his simple APRS antenna was showing up in the view of many of his lower cameras, so he set up this view just to catch the antenna in the act. It's a simple steel wire with a black plastic coating. This happened between 25k-35k ft and the antenna regained its, um..., rigidity again on the way back down while passing through the same altitudes. So does it do this because of the cold of the troposphere, or the heat from the sun? Sounds like we need to play with some dry ice again and a heat lamp.

Neck tie

Lucas tried an idea of leaving a large amount of the balloon's filler neck available to the balloon. That is, we tied off the balloon and secured the payload a good 10cm below where we usually wire-tie the balloon. The intention is to give a few more cubic centimeters of expansion area. This appeared to work well and we will use this in the future.

RF Cut down

The RF remote tree descender rig was not needed for recovery, but we set it off in the car on the ride home and it cut the bridle as expected. The nichrome heating LiPo battery is finicky so we need to find a better power source.

Camera heat

We've mentioned that our Mobius/808 cameras give off a lot of heat. During this flight the internal payload temp measured by the AP510 only went as low as 90F. It got as hot as 116F before touchdown and then shot well above that while awaiting our recovery.

Introducing the AP510

The AP510 Tracker with uBlox mod still needs some work. It worked really well up until about 38K ft, then it started acting strangely. We were ready for the possibility that the reported altitude could abruptly max out, but we then started seeing some really strange errors in Lat & Long as well. The unit then went completely silent for 40 minutes. Once the payload dropped back below 38K, it worked great again. We are working directly with the designer and we hope to try again soon with new firmware. This unit could become an inexpensive, feature-rich box for the HAB community. AND it speaks Bluetooth and is a TNC. Lots of cool project ideas come to mind.

APRS WIDE2-1 vs NONE

The Bee was set up with a single APRS path of WIDE2-1. This allows the big digipeaters to relay packets and helps out a lot at low altitudes (pre-flight testing and recovery), but at high altitudes you still run the increased risk of getting some late/duplicate packets injected into APRS -- from hundreds of miles away. These duplicates make it look like you are flying backwards at times.

We set the AP510 with a path of "NON" (sic) that so that digipeaters ignore the packets and it is just received by the few igates in the area. We were at 2400 feet in downtown Raleigh before the first packet reached an igate. Our last packet was 3700 feet on the way down. But there were no duplicate packets. We will test this again once we have the AP510 working at high altitude.

Reminder: Never use a path other than WIDE2-1 or NONE for HAB, or you will cause a packet storm. Also, we turn off 'smart beaconing' algorithms as they often get confused while swinging at the end of a long string.

Google Earth Live

Again during this flight, we were able to take advantage of having both the projected plot and the live plot both visible within Google Earth (remember to save your Habhub projections as a KML before flight). That's going to be key to being able to catch a payload someday. Also the live updating Excel spreadsheet let us keep an eye on live ascent/descent rates. We didn't see the drop in ascent rate before burst like we see on most flights, but it did start to show up on the on-board data (below) that was sampling every 10 sec.