Long wave because of the long wavelength needs impractically large antennas to broadcast with any reasonable efficiency The tallest ever man made structure before the Burj Khalifa was a longwave transmitter Warsaw radio mast Its ground wave range is also relatively long compared to medium wave which means that the transmissions will reach out over a much wider area 1000 km is not unusual That may sound like an advantage but at such low frequencies bandwidth is at a premium so the longwave band has to be rather small it s just over 100 kHz wide in Europe Combine those two effects and and what happens is that a single medium powered transmitter will swamp a very large area making that frequency unusable to anyone else and taking away almost 10 of the available frequency space within that wide area So the longwave band is good purely from a transmission effectiveness point of view if you ignore lightning interference but it doesn t work too well on a economical commercial level This is one of the reasons the FM band was moved from 50 MHz to its modern place after WW2 the higher frequencies are much more strongly localised to one area so there is room for a lot more stations in a given space and stations can cater more easily to smaller local audiences which keeps costs down and attracts more people A longwave transmitter for a single large city is silly but for VHF it works