[OKDXA] Big Anniversary Date...

[Kim Elmore]

On 12 Dec 1901, Marconi and his assistant, Kemp, believed that they had 
received the letter S sent from Poldhu, Cornwall, England, to Signal 
Hill in St. Johns, Newfoundland, Canada, and so are credited with being 
the forst to accomplish transatlantic wirelss communications.
Much later analysis raise issues arising about just what Marconi and 
Kemp heard and even if they heard what they say they did. Spark signals 
are very broad (as anyone that has heard one knows). While the antenna 
system is now thought to be resonant at about 500 kHz, Marconi never 
revealed what it truly was. Belrose (2006) suggests that the resonant 
frequency was around 500 kHz, Marconi said at various times 850 kHz, or 
135.4 kHz and Fleming (the transmitter designer) said 984 kHz. 
Regardless, the bandwidth of the transmitted energy was very wide. 
Almost the entire path was in daylight, meaning that D-layer absorption 
(about which no one had any idea) was high. We now know that the 
likelihood of a 150 kHz or even 984 kHz signal spanning the Atlantic on 
a daylight path is essentially zero. So, were Marconi and Kemp fooled? 
Did they make it up?  Keep in mind that the receive system was not 
resonant at all. Why Marconi chose a non-resonant system is unknown. 
Today, it is believed that if Marconi and Kemp did, in fact, hear 
signals transmitted from Poldhu, they were not between 150 and 984 kHz. 
Instead, the bandwidth of the transmitted signal was so broad that it 
included the then unknown “short waves.” Thus, if  Marconi and Kemp 
heard what they believed, they had to be short-wave signals. Yet, 
Belrose (2006) casts doubt even on this. It could also easily have been 
an artifact of the receiving equipment Marconi and Kemp used.

So, get on the air and make a transatlantic_spanning QSIO, or at least 
listen to a transtalantic signal. And considerthat a mere 120 years ago, 
there was no such thing.

Bolrose's work is here: https://ieeexplore.ieee.org/document/958784

-- 

Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP 
SEL/MEL/Glider, N5OP, 2nd Class Radiotelegraph, GROL)

/"A great second violinist plays second fiddle to no one." //– Robert C. 
Marsh, Chicago Sun-Times./