Is there any project, any commercial antenna
of such length, that allow me to work all band
7 - 14 - 21 - 28 MHz ?

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All dipoles of any reasonable length, inverted-V or not, commercial or home
brew, are quite efficient on all HF bands in that they all radiate most of
the power which is put into them. The problems lie in loss in the
transmission line and the essential tuner.

Erect the highest and longest dipole you can, feed it with open-wire line,
use a tuner appropriate for each band of interest and you won't be
disappointed.

Or better still, if you can manage it, erect the longest inverted-L you can
and feed it at one end tuned against a modest ground system such as a dozen
bent surface or shallow-buried radials.
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Reg, G4FGQ