Purpose of the first experiment was to test my new kite - HQ PowerSled 36 and its lifting capabilities. Smaller kites (like PowerSled 14) give too small pull to lift even 500g payload at moderate winds.
Final goal is to have platform that allows lifting a 1000g payload in winds at 10 km/h or greater.
Payload: custom made APRS tracker (based on Arduino Nano) with 5W Wouxun KG-UVD1P transmitter and GPS receiver. Antena was simple 144 MHz quarter-wave, unfortunately - bent 90 degree during experiment. Payload weight: about 600g.
Custom-made APRS tracker
Wind speed: 25 km/h - according to the Warsaw-Okęcie (EPWA) airport weather service.
Max altitude: 160 m above ground level (measurement based on GPS record). About 250m of kite line was used.
Longest RF signal path (based on http://aprs.fi measurment): 106 km
2013-07-13 17:17:26 CEST: SQ5OMQ-1>BEACON,WIDE1-1,qAR,SR5DRK:!5211.11N/02122.09E-TRACKER NA LATAWCU
2013-07-13 17:17:58 CEST: SQ5OMQ-1>BEACON,WIDE1-1,qAR,SR5DRK:$GPGGA,151724.000,5211.1068,N,02122.0938,E,1,07,1.1,227.4,M,38.8,M,,0000*56
SR5DRK station received over 14 consecutive APRS frames, so the RF path can be considered stable.
Experiment notes: At 25 km/h wind, PowerSled 36 gives so strong pull that it's very difficult for 2 persons to get it back on ground. Heavy, electric engine powered line winder is needed for further experiments. Construction of such winder is under way.
Goal for the next experiment: Tests of the winder, reaching altitude of 300m above ground level. Different mount of the radio antenna to get better efficiency.
HQ PowerSled 36
Kite and transmitter in the air