
The Electrical Experimenter (1913) - georgecmu
http://library.si.edu/digital-library/book/electricalexperi04gern
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gravypod
I'd buy a re-print of these. These would go great in my college's ham shack.
This is the kind of stuff that I imagine Marconi doing in his lab while
smoking a cigarette and talking about airplanes being invented or something.

It's got some great projects for anyone who's looking to get into radio. Check
out page 100 for an example of one of those crazy projects. It looks like it's
a 50-foot areal hooked up to a 4-tap isolation transformer being AC coupled to
headphones. It's using a basic single diode detection circut (you can check
EEVBLog's latest video to see them being used in the spy bug detector). Nifty
stuff and remindes me of fox hole sets

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analog31
I think that in some sense, the old radio magazine project articles are the
original open-source hardware. There was certainly a tradition of developing
something useful, and then sharing it with the world.

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Animats
Not quite. Look at all those ads in the back for patents, patent attorneys,
and related services. Back then, the big thing was to be an inventor with
patents. Tesla, Edison, Bell, DeForest, etc. all had strong patent protection.

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gravypod
How many people violated Tesla's patents? It's all in the character of the
person not in whats written on paper. Tesla didn't care what you did with his
stuff so long as you weren't an outright dick and you were attempting to learn
something.

Google the quote "Marconi is a good fellow. Let him continue. He is using
seventeen of my patents." for more back story.

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kbart
Heh, it's funny to see that ads haven't changed much in 100 year: "buy this
book, learn at home and earn tons of money!" etc., just change
web/cloud/mobile with auto/electric/radio.

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kalleboo
Interesting that the Smithsonian is cataloging/embedding Internet Archive
material. A cursory web search doesn't turn up any history of their
collaboration, is the Smithsonian just indexing the IA?

Here's a direct link to the PDF if you prefer that over the JavaScript reader
[97 MB]
[https://archive.org/download/electricalexperi04gern/electric...](https://archive.org/download/electricalexperi04gern/electricalexperi04gern.pdf)

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digikeri
Smithsonian Libraries has been working with IA since 2006 to digitize our
public domain material. We put it all on IA, but we also iframe the books on
our site so we can create "collections" and have landing pages that let you
browse all volumes of a given serial (among other things).

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jhallenworld
Page 808: DeForest vs. The Electrical Experimenter. DeForest was trying to
prevent advertisements of Audion clones.

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csense
The article on solar power on page 316 is really interesting. Especially the
artist's conception of a surprisingly modern looking solar panel, especially
given that this was long before semiconductors were really understood.

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dwpdwpdwpdwpdwp
This is great. I wonder how many of the radio devices advertised or described
in here would even be legal to operate today.

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a_thro_away
On page 89 in the book Marconi's remote controlled boat doesn't talk about the
transmitter (that I saw), but used a coherer as a receiver detector, something
like a primitive diode I think. But if so, they probably used a spark gap
transmitter attached to a long wire antenna, but splattered energy across a
huge electro spectrum and traveled very very far, quite disruptive to any
other receiver on all different wavelengths. Marconi used one of these for the
first transatlantic wireless test as I recall. I remember books used to show
you how to build one from a model A automobile coil IIRC, but I don't think it
would be long before the FCC would knock on your door and would not be happy
as they would maybe have to triangulate your location from different states?.
A real Ham can verify all this, but I loved to pore over the old magazines,
electronics, being old enough to search it out in the junk piles that were
quite common before the 1970s.

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cr0sh
> but used a coherer as a receiver detector, something like a primitive diode
> I think

From my understanding, a coherer was a radio-wave detector that used ferrite
particles (in a small sealed glass tube, with wire at each end) that - when
the radio signal was strong enough - would "stick together" and form a
circuit; you can think of it as an RF-activated "reed switch" or relay. It was
very crude, and not easily tunable.

Also - another interesting tidbit of info about early wireless: In order to
generated the higher carrier-wave frequencies, they used special multi-pole
alternators spun at high speed. Rather than only having a few poles, like a
regular power generator, these RF alternators would use sometimes hundreds of
poles. The RPM, multiplied by the number of poles, would determine the
frequency of the output signal carrier wave. This was mainly used for
telegraphy; I'm not sure if these machines had the bandwidth for voice. At the
same time, they still produced a ton of power like a standard alternator - so
it was essentially a way to generate "high power" (100s to 1000s of watts) RF
(in the KHz ranges).

Another early technology of the time (used for a variety things - including
motor control) was something called "magnetic amplifiers"; they are
essentially weird variations on standard AC transformer technology. They can
be made to act as audio amplifiers, as well as switches (like a vacuum tube or
transistor).

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a_thro_away
Agreed on the coherer, and on the motor-generator combos, but that seemed to
be later than 1916? I understand that the coherers hated the broad spectrum of
the spark-gap, so who knows?

