How radios work

From antenna to speaker, and microphone to antenna.

Receiver basicsFrom antenna to speaker.The superheterodyne receiverMixing everything to one intermediate frequency.Direct conversion and SDR receiversSkipping the IF with I/Q sampling.Transmitter basicsOscillator, modulator, driver and final amplifier.The transceiver, end to endHow one box does both jobs.Sensitivity, selectivity and dynamic rangeThe numbers that describe a receiver.AGC, noise blankers and noise reductionTaming level changes and noise.Filters in radiosRoofing, crystal, mechanical and DSP filters.RIT, XIT and split operationOffsetting receive and transmit frequencies.