How We Went From Tapping Code to Radio Shows

Karl W4KRL W4KRL at
Tue Jan 29 19:27:40 CST 2008


I also wondered how the AM signal could be demodulated. According to
Wikipedia, Fessenden invented the hot wire barretter in 1902 so it is
possible that some stations were equipped with this demodulator prior to his
1906 transmission. Presumably there was at least one other station equipped
to receive his signal but it strains credulity to claim that stations "up
and down the coast" heard his transmission.

73 Karl W4KRL

-----Original Message-----
From: at
[ at] On Behalf Of Tom Azlin,
Sent: Tuesday, January 29, 2008 5:34 PM
To: W4KRL at
Cc: tacos at
Subject: Re: How We Went From Tapping Code to Radio Shows

Hi Karl,

What kind of receiver did the young United Fruit Company operator use to 
listen the the 1906 Fessenden broadcast? Would they have had a coherer 
detector since that was the common detector? Doesn't a coherer require a 
vibrator to decoherer so that the circuit can be broken.   Wouldn't a 
standard ship board receiver thus be incapable of receiving AM audio 
signals?   why would one of those ship board stations have had the type 
of receiver that that could demodulate Fessenden's signal?  Is there any 
evidence that the United Fruit Company standard Spark station had a Hot 
wire barretter detector?

73, Tom n4zpt

Karl W4KRL wrote:
> Famous Engineers > How We Went From Tapping Code to Radio Shows
> It’s Christmas Eve, 1906. A Morse code operator on a United Fruit ship in
> the Atlantic Ocean moves closer to his receiver. Instead of the usual,
> primitive taps of Morse code, he hears a man speaking over the receiver,
> followed by music. And so began the world’s first long distance radio
> transmission.
> The man’s voice heard up and down the Eastern seaboard that night was
> Professor Reginald Fessenden. But, that historic night was made possible
> an alternator developed by a young engineer who had recently emigrated to
> the U.S. from Sweden.
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