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It would be considered illegal under Part 15.219. But from the experimenters viewpoint, it would be fun to try – temporarily.
You could claim operation under Part 15.209 which does not limit the antenna system but rather the field strength. And if/when they do come around to inspect they will cite Part 15.209 anyway and nail you for excessive field strength.
Long wire antennas can be used as transmitting antennas but as I previously stated you would need some type of tuner to resonate the antenna if not the proper length. Otherwise the mismatch between the transmitter and antenna impedance would reduce the field strength considerably. Which then again, you could be legal but end up with about 200 feet of range.