I have seen discussion of topfed dipoles as antenna and recognise that
they have two 'features': 1 They are are frequency specific 2 they are
directional.

However I have seen decriptions of off-centre-fed dipoles with baluns
that cover all ham bands, I have not seen numbers for their performance
on other frequencies. It seems to me that these would be a very
convenient solution; a 4:1 balun at the masthead fed by coax and
feeding (eg) forestay and backstay with appropriately placed
insulators.

Comments ?