AM transmission tower signal rectified in electric arc to generate audio

[davenn]

This short YT video isnt about the AM rectification, it was about why you dont touch transmitter towers

I just noted that the audio of the signal could be heard as the guy was generating an arc

Pretty cool .....



cheers
Dave

 

[Tom.G]

Perhaps a closer description than 'rectified' would be 'demodulated' or 'detected'.

You could hear the audio because AM is Amplitude Modulation. That means the instaneous instantaneous transmitted power is proportional to the audio waveform amplitude at that instant in time.

At zero audio amplitude (silence or zero-crossing of the audio waveform) the transmitter is emitting its nominal power - for instance a 1kW transmitter is putting out 1kW.

If the transmitter is being 100% modulated, the positive peaks of the audio cause the transmitter to emit 2kW; and the negative audio peaks cause Zero transmitter emission.

This power variation causes the arc intensity to vary as the incoming audio varies, thus allowing you to hear the audio modulation.

Enter Amplitude Modulation into Google search for more than you ever wanted to know.

 

[davenn]

Perhaps a closer description than 'rectified' would be 'demodulated' or 'detected'.

You could hear the audio because AM is Amplitude Modulation. That means the instaneous transmitted power is proportional to the audio waveform amplitude at that instant in time.

At zero audio amplitude (silence or zero-crossing of the audio waveform) the transmitter is emitting its nominal power - for instance a 1kW transmitter is putting out 1kW.

If the transmitter is being 100% modulated, the positive peaks of the audio cause the transmitter to emit 2kW; and the negative audio peaks cause Zero transmitter emission.

This power variation causes the arc intensity to vary as the incoming audio varies, thus allowing you to hear the audio modulation.

Enter Amplitude Modulation into Google search for more than you ever wanted to know.

All good info

yes, I am a radio operator / technician
got my license back in the days of long answers and drawing circuit diagrams

 

[davenn]

@berkeman thanks for the edit