Prediction for the Fish Fest Balloon

We’re planning to launch a small 300g Hwoyee ballon this time from Fish Fest at Lake Livingston TX. I ran a preliminary prediction with the CUSF Landing Predictor:

PredictionFishFestBalloon

The track is very unusual, probably because you can’t really predict the wind direction this time of the year. However crossing the Mississippi seems to be a general problem. We’ve had this issue already on an earlier flight.

The Surface winds will be very calm in the morning, getting stronger towards evening with quite some turbulences above New Mexico and North Texas:

The general weather forecast looks favorable for a balloon launch. Maybe a bit hot as usual…

WeatherForecastFishFest

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PecanPico3

Yesterday I built the first complete PecanPico3 Tracker with a Si4464 transceiver chip. This is Serial #2. Serial #1 was only partially populated because I was hesitating to put an expensive GPS chip on the PCB without knowing if it works.I’ve had problems with PecanPico2 to couple the oscillator signal into the Si4464 and it turned out that I needed to attach the signal to the XOUT pin instead of the XIN pin. More experimenting showed that a 22 pF coupling capacitor is optimal for a stable operation of the Si4464. The theoretical value of 4 pF was too small and the PLL didn’t always lock to the correct frequency. However, this version of PecanPico3 seems to work fine just out of the box

PecanPico3

Here are some example packets that can be seen on aprs.fi:

2013-05-13 20:17:17 CDT: KT5TK-2>APECAN,WIDE2-1,qAR,KT5TK-6:T#224,072,000,000,000,019,00000000
2013-05-13 20:17:30 CDT: KT5TK-2>APECAN,WIDE2-1,qAR,KT5TK-6:/011506h2943.53N/09530.47WO000/000/A=-00179  3.8V 28C 101987Pa http://tkrahn.net
2013-05-13 20:19:45 CDT: KT5TK-2>APECAN,WIDE2-1,qAR,KT5TK-6:T#225,072,000,000,000,019,00000000
2013-05-13 20:19:58 CDT: KT5TK-2>APECAN,WIDE2-1,qAR,KT5TK-6:/011732h2943.53N/09530.48WO000/000/A=-00179  3.8V 28C 101987Pa http://tkrahn.net
2013-05-13 20:22:13 CDT: KT5TK-2>APECAN,WIDE2-1,qAR,KT5TK-6:T#226,071,001,000,000,019,00000000
2013-05-13 20:22:26 CDT: KT5TK-2>APECAN,WIDE2-1,qAR,KT5TK-6:/012001h2943.53N/09530.47WO000/000/A=-00181  3.8V 28C 101993Pa http://tkrahn.net
2013-05-13 20:24:41 CDT: KT5TK-2>APECAN,WIDE2-1,qAR,KT5TK-6:T#227,071,000,000,000,019,00000000
2013-05-13 20:24:54 CDT: KT5TK-2>APECAN,WIDE2-1,qAR,KT5TK-6:/012232h2943.54N/09530.46WO046/016/A=-00181  3.8V 28C 101993Pa http://tkrahn.net
2013-05-13 20:27:09 CDT: KT5TK-2>APECAN,WIDE2-1,qAR,KT5TK-6:T#228,073,001,000,000,019,00000000

The tracker is up on air for nearly 6 hours on a 400 mAh NiCd battery and still going. This made my decision easy for next Saturday where we’ll launch a 300 g balloon from our Fishfest QTH (Lake Livingston TX).  Pecan3 will fly!

Schematic: PecanPico3

Arduino Code: https://github.com/tkrahn/PecanPico

Here is my parts list: http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=33053ee4fd

The uBlox MAX6Q GPS is available from HAB Supplies