There is such a diverse opinion about antennas both little and large and
modes one versus the other that the best course of action is for each
individual to build and use what they think is best for them.
There is an abundance of theoritical discussion going on that bears no
relationship to REALITY.
Too many assumptions, and too wide of the mark when one tries to
implement them.
The real proof of success will be judged by listening on LF to signals
being emitted from the various sources. Those doing the job properly
will be obvious from the strength of the signals received.
Data modes would not fair very well today with static crashes S9 plus
40, but I could manage a short exchange of RST and callsign on CW
without difficulty.
73 de G3KEV