Why an antenna cannot receive analogue baseband signal of 0-4000Hz?
If you want to send out a signal a 4 KHz, then yes, for the most part we can’t make a resonant antenna due to the size constraints (but take a look at the naval ELF submarine antennas). However, by modulating the frequency at a much higher carrier frequency, then we only need to receive at the carrier frequency. So if the carrier frequency is say 62 KHz, then we can design an antenna, but it will still be friggin huge. I think MHz would be a better starting band for carrier frequencies as we have seen with radio and television standards.
