Balloon on its way

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DD4WV
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Last seen: 4 days 4 hours ago
Joined: 2017/09/14 - 11:01
Balloon on its way

Hi all,

I started a balloon (well, 3 tied together) with a WSPR payload this morning near Berlin. It uses my callsign DD4WV and the balloon call 0X0, zeroes as first and third character. The payload is solar powered, the marvelous ST SPV1040 buck converter brings the voltage up to 4.9V for a supercap. GPS ist uBlox MX-8, processor is a MSP430 from TI. The transmitter is a SI5351, little more than 10mW. It uses a vertical dipole, a thin copper wire knotted to a fishing line, 5m up to the ballon and 5m down ;) . The total mass is 13gr for the payload and 2gr for the antenna. I use 3 Qualatex 36'' balloons with an initial drag of 18gr. The setup leveled out at 10100m/-5°C and is on its way east over Poland with 30km/h. I hope to hear the last message at 17:30 UTC today from near Bydgoszcz/Poland ( I hope!). The supercap is serving only as backup for the GPS data during the night to speed up synch in the morning. It has not enough energy to keep synch and transmitter alive during the night.

It is my second trie. First attempt bursted in 10000m after a 5h flight. Trading intial drag against overpressure at floating level is tricky business, but this balloon is floating at 10100m as calculated. Until now everything seems to be ok. My goal is to stay airborne for 4 days. NOAA https://ready.arl.noaa.gov is promising a position in Mongolia for this timeframe, we will see.

Big fun anyway.
Cheers
73
Detlef
DD4WV