11. Basic flight connections
The HF antenna needs 1/4-wavelength on each leg (for example, each leg is 5m for 20m
operation). A typical flight configuration has the top end of the top leg tied to the balloon, and the
U4B payload suspended directly in the middle of the dipole.
The GPS antenna can be made of simple #28 (0.3mm) enameled wire; a 1/4-wave at 1575Mhz is
about 45mm. The feedline consists of 1-inch of twisted wire, about 6 turns works well.
The above is just an example of a minimal flight tracking system. You can add your own sensors
and complexity as you see fit!
There are a lot more practical tips about flight system preparation and launch, in the FDIM 2021
Conference proceedings article at
http://qrp-labs.com/u4b
U4B hardware Rev 1.00
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Summary of Contents for U4B
Page 1: ...U4B U4B Ultimate4 Balloon tracker Hardware manual U4B hardware Rev 1 00 1 ...
Page 7: ...5 Track layout 6 GPIO pins 8 18 pad locations U4B hardware Rev 1 00 7 ...
Page 8: ...7 Parts layout top side 8 Parts layout bottom side U4B hardware Rev 1 00 8 ...
