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Electronics => RF, Microwave, Ham Radio => Topic started by: prabhatkarpe4 on November 01, 2024, 09:24:35 am

Title: Why do most pocket AM radio receivers have shorter (non-resonant) antennas
Post by: prabhatkarpe4 on November 01, 2024, 09:24:35 am

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?

Title: Re: Why do most pocket AM radio receivers have shorter (non-resonant) antennas
Post by: Andy Chee on November 01, 2024, 10:15:43 am

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.

Title: Re: Why do most pocket AM radio receivers have shorter (non-resonant) antennas
Post by: Andy Chee on November 01, 2024, 11:46:27 am

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/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/shorter-whip-antenna-of-the-pocket-radios/)

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