Test - 2018-05-10


This primarily was a second test launch of the WSPR transmitter for testing range.

However, the launch went well and so the flight details are outlined below.

Tracker Details

Tracker Type: WSPR

Model: PicoTrackerWSPR1

Powered by 2 AAA batteries

Launch Parameters

Balloon and Payload

  • 36" Qualatex, unstretched
  • 31.5 gram payload (used green wire wrap wire instead of the 36 gauge wire from last time)
  • 3.4 grams free lift


Predicted Internal Pressure: 2.28 kPa

Predicted Altitude: 17,552 ft

3 day prediction


  • Top Altitude - 25,000 ft
  • Duration - 22 hours, 16 min
  • Distance - 1,200 miles great circle
  • Cause of death - Unknown if actually flying or not. Batteries probably died given it was running the GPS nearly 50% of the time.


  • TX Distance - 3,900 miles
  • Distance record - 1,200 miles

General Thoughts / Observations

Not sure why the actual 25k altitude is much higher than the predicted 17k.

To avoid the very long antenna wire from becoming tangled on launch (which happened last time), I decided to roll the whole thing in paper.

This helped, but there were still tangling issues at launch, mostly to do with the paper not unrolling very far on its own, and my needing to hold the neck or at least the ribbon of the balloon.

Further the paper would blow around and wrap around parts of the antenna not yet unrolled.

Two people would be helpful.