Simple wire and a stick makes a good performing antenna, under the roof, above or aside the roof.
Easy way to adjust the frequency without cutting the wire.
Instead of twisting the wires you could also be kept close together by a tywrap that could be slided over the two wires.

Not critical but I forgot to mention what wire I used: 0.5 mm2 insulated flexible copper wire.

Simulation and measurements are performed about 10 meter above ground.