Air variable capacitors

[Jimmyz]

Hello. based on what i see. Air variable capacitors no longer seem to be used in radios. what electronic component has replaced them? Thanks

 

[Harald Kapp]

FIrst varactors (also called varicaps) were used.
Today tuning is mostly done digitally, eg. by synthesizing the local oscillator signal for a superhet's mixer.
Or completely in the digital domain by undersampling (look up SDR - software defined radio).

 

[bertus]

Hello,

There is speciality shop where there are many available:
https://www.die-wuestens.de/dindex.htm?/k6.htm

Bertus