[CW] Continuous Wave much better than spark

Thu May 6 17:30:47 EDT 2021

    I think you have some of this backward. The alternator 
originated with Fessenden, although there were earlier attempts. 
He took his machine to General Electric who assigned it to 
Alexanderson to develop. Alexanderson and Fessenden had a 
disagreement about how to make the machine. Alexanderson's 
version is the one that was successful. AFAIK Westinghouse had 
nothing to do with it.
    The arc converter originated with Poulsen, who also invented 
the magnetic recorder (intended for telegraph recording). The 
patents were bought by Cyril Elwell and developed by a new 
company, originally called Poulsen Telegraph but changed to 
Federal Telegraph. This machine was far more efficient than the 
existing spark transmitters and Elwell and his company was able 
to demonstrate it to the U.S. Navy who bought many of them for 
both land and ship stations. The arc machines were largely the 
produce of Leonard Fuller, who was the chief engineer of Federal. 
When the Federal board refused to extend Federal's successful 
radio telegraph network to the near east Elwell resigned and 
Fuller took over the company. Federal built arc converters up to 
one megawatt in size.
     Beside perfecting the alternator Alexanderson invented a 
form of magnetic  amplifier to act as a modulator. This allowed 
very high speed CW transmission and some voice transmission. It 
is often stated that Fessenden made the first radio broadcast, in 
1906, but recent investigators are unable to find any evidence 
that he actually did that. It may be urban myth. Fessenden, while 
a truly brilliant inventor, was also very good at self promotion 
and was reportedly a very difficult man to get along with. There 
is no doubt he was thoroughly cheated in some of his early 
attempts to operate a business.
     Among other alternator forms was the Goldschmitt machine, 
which used an electrical frequency multiplier. Goldschmitt 
machines were installed by a German company called HOMAG in 
Tuckerton N.J. These were not very reliable and when the Navy 
took over the Tuckerton station were replaced with Alexanderson 
machines.
    See Thorn Mayes book and Howeth's book for much more.
    Marconi was well aware of the shortcomings of spark. That's 
why he was anxious to acquire the G.E. Alexanderson machines. 
After WW-1 RCA was created to prevent any non-U.S. entity from 
controlling communication in this country or from becoming the 
kind of world wide monopoly the British had on undersea cable. It 
was more than simply buying out Marconi's U.S. interests, there 
was legislation passed that made it a requirement that radio in 
the U.S. be owned and controlled by U.S. citizens which forced 
the sale of American Marconi to the consortium that formed RCA. 
While Westinghouse became a member of this consortium it did so 
after the formation of RCA and bought into it with its receiver 
patents, mostly from Armstrong and its early development of 
broadcasting. Note that RCA was formed mainly as a communication 
company and a patent holding company before broadcasting 
developed. Broadcasting turned out to be a far larger market than 
communications and RCA was fortunate to be able to develop it.
    Thorn Mayes book is very valuable. It must be read as an 
adjunct to other histories. IMO the best one to start with is 
"Communications and Electronics in the United States Navy" by 
Howeth, which is available free on line but is not hard to find 
at reasonable cost in hard cover.
     The development of vacuum tubes and of short wave 
communication pretty much eliminated the importance of the 
Alexanderson machines. RCA's giant communication center "Radio 
Central" on Long Island was never completed because the circuits 
it was intended for could be handled better and cheaper via short 
wave. Only two of ten alternators and segment loaded antennas 
were ever installed there. They proved to be extremely reliable 
and stayed in service for years but future circuits there and 
elsewhere were handled by short wave. GE built twenty 
Alexanderson machines, only one still exists, in Grimeton in 
Sweden, its on the air one day a year (SAQ).

On 5/6/2021 11:26 AM, D.J.J. Ring, Jr. wrote:
> Continuous Wave much better than spark transmissions, much 
> narrower in bandwidth, more efficient.
>
> Both the Ernst Alexanderson Alternator (1904) developed by 
> Westinghouse in Massachusetts and used by American Marconi, 
> later Radio Corporation of America (1919) and Danish inventor 
> Valdemar Poulsen's arc transmitter (invented 1902, Lyngby, 
> Denmark) were continuous wave emission transmission 
> transmitters. Dr. Reginald Fessenden, a Canadian inventor and 
> professor of physics took General Electric's alternator and 
> with his own engineers in Washington, D.C. increased the output 
> frequency from a nominal 15 kHz to around 67 kHz and shipped 
> the modified alternator to the Brant Rock village of 
> Marshfield, Massachusetts (about a mile from where I am now.) 
> It was with this alternator that his company, National Electric 
> Signaling Company (NESCO) transmitted both continuous wave 
> Morse and continuous wave modulated radiotelephony with 
> December 1906 Christmas broadcasts "... first a short speech by 
> me saying what we were going to do, then some phonograph 
> music.... Then came a violin solo by me ... which I sang one 
> verse of, in addition to playing the violin, though the 
> singing, of course, was not very good. Then came the Bible 
> text, Glory to God in the highest and on earth peace to men of 
> good will, and we finally wound up by wishing them a Merry 
> Christmas and then saying that we proposed to broadcast again 
> on New Year's Eve. "
>
> Valdemar Poulsen's arc transmitter 
> https://ethw.org/Milestones:Poulsen-Arc_Radio_Transmitter,_1902 
> <https://ethw.org/Milestones:Poulsen-Arc_Radio_Transmitter,_1902>
>
> Thorn Mays article on 200 kW Alexanderson Alternator 
> http://www.navy-radio.com/xmtrs/vlf/alexanderson-mayes-1975.pdf 
> <http://www.navy-radio.com/xmtrs/vlf/alexanderson-mayes-1975.pdf>
> https://ethw.org/Milestones:Alexanderson_Radio_Alternator,_1904 
> <https://ethw.org/Milestones:Alexanderson_Radio_Alternator,_1904>
>
> Reginald Fessenden biography https://ethw.org/Reginald_A 
> <https://ethw.org/Reginald_A>
> Fessenden Brant Rock NESCO Christmas broadcast December 1906. 
> https://ethw.org/Fessenden%27s_Christmas_Eve_Broadcast 
> <https://ethw.org/Fessenden%27s_Christmas_Eve_Broadcast>
>
>
> 73
>
> DR
> N1EA
> .
>
>
>
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> =30=

-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL