Private Lines
About Private Line

Private Line covers what has occurred, is occurring, and will ocurr in telecommunications. Since communication technology constantly changes, you can expect new content posted regularly.

Consider this site an authoritative resource. Its moderators have successful careers in the telecommunications industry. Utilize the content and send comments. As a site about communicating, conversation is encouraged.

Writers

Thomas Farely

Tom has produced privateline.com since 1995. He is now a freelance technology writer who contributes regularly to the site.

His knowledge of telecommunications has served, most notably, the American Heritage Invention and Technology Magazine and The History Channel.
His interview on Alexander Graham Bell will air on the History Channel the end of 2006.

Ken Schmidt

Ken is a licensed attorney who has worked in the tower industry for seven years. He has managed the development of broadcast towers nationwide and developed and built cell towers.

He has been quoted in newspapers and magazines on issues regarding cell towers and has spoke at industry and non-industry conferences on cell tower related issues.

He is recognized as an expert on cell tower leases and due diligence processes for tower acquisitions.

« Tech time! Always more on modulation . . . | | Chinese communal telephone service »

October 29, 2003

Posted by Tom Farley & Mark van der Hoek at 03:09 AM

Marconi's 1901 trans-Atlantic radio transmission questioned

It's accepted that in 1901 Marconi received the first trans-Atlantic radio signal, the letter "S", three clicks, tapped out in Morse code. Don Kimberlin now questions that accomplishment in a well written and researched article, "Investigating Radio's Roots: What Did Marconi Hear? The World's Most Heralded Radio Failure." The article is in .pdf form:
http://www.oldradio.com/archives/jurassic/marconi2.pdf (external link)

There's do doubt Marconi's team transmitted a single "S" from Poldhu in Cornwall, near Land's End. But did Marconi actually receive it? Or did he and the sole witness to the event hear something else? Something they mistook for the signal? I've written many times how difficult it is to determine radio firsts; Marconi's claim now proves equally hard to establish. Time to rewrite the history books. Again.

Update. In response to my question to Don, How could an experienced operator like Marconi confuse telegraph dashes for lightning produced static?, Kimberlin responds:

Tom:

How did Marconi might mistake lightning for his desired signals? The key lies in the sound he wanted to hear.

Perhaps I didn't speak enough to the point of the way they had tuned the Poldhu spark transmiter. At the time, their financial strain was such that in order to minimize stress on the Poldhu transmitter, they had reduced the duty cycle of the spark to such a short period that each "key down" on the transmitter produced only a very short "click" of transmission, not the "buzz" we are accustomed to expect from a Type B emission. That way, heating and possible damange while producing maximum power at Poldhu was reduced.

Certainly, Marconi had heard lighting before, but here he was expecting merely a train of 3 clicks in an earphone. They could as easily have come from a natural source as from his transmitter.

I think what is key here is to have some understanding of just how much more favorable a south-north equatorial transmission path is than an east-west one. I may be more sensitive that difference than most people who are not HF propagation specialists, merely because I worked in AT&T's HF radio plant at Fort Lauderdale, FL -- a place that ran largely north-south paths in the equatorial region. It meant we could run commerciallly suitable links most any day of most any part of the solar cycle - high or low - while the AT&T plants at New York and San Francisco often had days of downtime, particularly in lows of the solar cycle.

And, December 12, 1901 was the lowest of low -a day of absolutely zero sunspots.

Since writing the article, it has crossed my mind there could have been a minor geomagnetic storm, which would be highly unlikely, and I can't rule out one of the annual meteor showers, and I intend to correspond with an expert or two on those. I rather expect their opinion will be neither of those as a cause on 12/12/1901.

Don Kimberlin

Post a comment

(If you haven't left a comment here before, you may need to be approved by the site owner before your comment will appear. Until then, it won't appear on the entry. Thanks for waiting.)

Human Verification:

Article Index

Recent Posts

Powered by
Movable Type 3.2