Build an HF Long Wire Balloon Antenna
If you anticipate calm wind conditions at your ARRL Field Day event, then this balloon-supported long wire antenna may be what you need for 160 meter / 80 meter antennas.
In this video from the "HamRadioConcepts Amateur Radio Video Channel", we see how such a project is designed, built, and tested in a real Field Day situation.
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Here are some comments from the video:
We made a long wire vertical antenna suspended from a helium balloon over the river, at 25 watts and an MFJ 993b autotuner to tune it on 40 meters at field day 2016 at the Wabasso causeway north of Vero Beach Florida. It was a successful antenna and worked very well at around 25 watts.