Can an audio amplifier be used to transmit or receive radio signals?

[ofosot69]

Is it possible to make an audio amplifier transmit radio signals when connected to its output with a ferrite coil or any other loop antenna and make the signal receive with another audio amplifier?

I have this question in my mind because of these reasons:

1. An audio amplifier can respond to frequencies from 20 Hz to 20 kHz and when connected with a speaker, the coil in the speaker resonates as per the output frequency and if that can be connected to a loop antenna instead, it should radiate radio waves too.

2. While experimenting with a tape recorder many years ago, I encountered one strange thing. While I was adjusting the screw of the tape head, the screwdriver accidentally touched one of the head connectors that was connected with the audio amplifier. And I was able to hear an AM radio station. I guess the screwdriver was working like a whip antenna and the tape head was working like a loading coil.

So, based on these facts, I am assuming that a audio amplifier is able to transmit or receive radio frequencies without the need of any carrier wave. This would be done using direct induction just like how a matching transformer works between an audio amplifier and a speaker.

 

[Nigel Goodwin]

Basically - NO - your entire premise is incorrect.

What can be done, and commonly is, is a loop system for deaf people.

You have a number of turns of wire around a room, perhaps three - using three core mains wire - you connect the speaker output of an amplifier to it, and the hearing aids contain magnetic receiver, allowing the deaf people to hear the audio sent to the loop.

But it's magnetic, not radio. Essentially it's a room sized transformer.