the Marconi's trasmitter was a spark tx, with many harmonics and no
selective filters ..
It possible what the transatlantic contact was made using the 3° or
higher harmonic ???
73 de Mauro IK1WVQ
At 18:07 22/08/2015, Markus Vester wrote:
Hi Fausto, LF,
>> do not forget that in 1901
Guglielmo Marconi received a signal across the Atlantic at a frequency
around 500 kHz
...did he really? I think there is some
doubt around this story. With a coherer, it would be very hard to prove
the difference between receiving a signal consisting of just three dots,
and false triggering by random statics. Considering a situation where a
success was badly needed, the reception may well have been the result of
wishful thinking.
http://www.antiquewireless.org/uploads/1/6/1/2/16129770/45-did_marconi_receive_transatlantic_radio_signals_in_1901.pdf
http://www.antiquewireless.org/uploads/1/6/1/2/16129770/46-did_marconi_receive_transatlantic_radio_signals_in_1901.pdf
Today we'd simply say "show us the
screenshot" ;-)
Best 73,
Markus
From: Fausto Coletti
Sent: Friday, August 21, 2015 9:59 PM
To:
[email protected]
Subject: Re: LF: Re: Band is open to VK!
:-)) I have a 8 motor drone but can
fly only 20 minutes with one Kg payload.
A kite or baloon is better.
Seriously speaking, the difficulties are very big, as rightly says Stefan
160 meters band, has a very different behavior but, do not forget that in
1901 Guglielmo Marconi received a signal across the Atlantic at a
frequency around 500 kHz and with a receiver that in comparison with
those of today was a tack. Ok were "only" 3500 Km.
Today what are we doing more with our ultramodern equipment?
Today we have SDR, filters, DSP, noise reducer, Marconi at Signal Hill
had a drop of mercury.
Today obtain a considerable power is relatively easy and inexpensive,
114 years ago there were only Ruhmkorff coils then, how much power was
actually radiated
no one ever taken the trouble to measure it.
But as they did then my compatriot to get those great results: trying,
trying and trying again trying to improve something every day.
The important thing is to think that nothing is impossible, maybe
improbable but not impossible.
Tonight I bored with the history of telegraphy...:-)
73, Fausto IK4NMF
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