Why do most pocket AM radio receivers have shorter (non-resonant) antennas

[prabhatkarpe4]

I would like to know why most pocket radios come with a shorter whip antenna of about 20 cm, which is not a resonant one for FM or SW bands. So, how come they work like that?

[Andy Chee]

Antennas do not have to be resonant to work.

Receiving antennas intercept the E-field from the transmitter, and the larger it is, the more E-field is intercepted, and the bigger the received signal.

Resonance is an advantage, but not necessary.

[Andy Chee]

Also, do not start new topic.  You already have threads here:

https://www.eevblog.com/forum/rf-microwave/why-do-pocket-radios-have-small-antennas/

https://www.eevblog.com/forum/rf-microwave/shorter-whip-antenna-of-the-pocket-radios/

https://www.eevblog.com/forum/rf-microwave/why-a-longer-antenna-is-able-to-receiving-smaller-bands/