6 ms·

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

akiselev 10y ago
This book is almost a thousand pages long so I haven't done an exhaustive search but based on a random sampling... none. The first page I stumbled on was the "Experimental Chemistry" intro (page 110) and, after a paragraph on the virtues of buying stoppered beakers custom engraved with chemical symbols, it listed asbestos as the first piece of equipment. I'm going to (safely) assume that a book written before we knew about carcinogens or sharpies probably doesn't contain designs that would meet modern FCC electromagnetic interference standards. Hell, a significant portion of the things described in this book would be grounds for OSHA penalties and class action lawsuits if carried out in a work place. On a side note: oh, how times have changed: (pg 942) Horse Sense If you work for a man, in heaven's name work for him. If he pays wages that supply you your bread and butter, work for him, speak well of him, think well of him, stand by him, and stand by the institution he represents. I think if I worked for a man, I would work for him. I would not work for him a part of his time, but all of his time. I would give an un- divided service or .none. If put to a pinch, an ounce of loyalty is worth a pound of cleverness. If you vilify, condemn and eternally disparage, why, resign your posi- tion, and when you are outside, damn to your heart's content. But, I pray you. so long as you are a = part of an institution, do not con- demn it. Not that you will injure — the institution — not that — but when you disparage the concern of which you are a part, you disparage your- self. — Elbert Hubbard.
a_thro_away 10y ago
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.
- cr0sh 10y ago
  > 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).
  - a_thro_away 10y ago
    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?
johansch 10y ago
Page 314: Killing Sharks by Electricity

akiselev 10y ago

This book is almost a thousand pages long so I haven't done an exhaustive search but based on a random sampling... none. The first page I stumbled on was the "Experimental Chemistry" intro (page 110) and, after a paragraph on the virtues of buying stoppered beakers custom engraved with chemical symbols, it listed asbestos as the first piece of equipment. I'm going to (safely) assume that a book written before we knew about carcinogens or sharpies probably doesn't contain designs that would meet modern FCC electromagnetic interference standards. Hell, a significant portion of the things described in this book would be grounds for OSHA penalties and class action lawsuits if carried out in a work place. On a side note: oh, how times have changed: (pg 942) Horse Sense If you work for a man, in heaven's name work for him. If he pays wages that supply you your bread and butter, work for him, speak well of him, think well of him, stand by him, and stand by the institution he represents. I think if I worked for a man, I would work for him. I would not work for him a part of his time, but all of his time. I would give an un- divided service or .none. If put to a pinch, an ounce of loyalty is worth a pound of cleverness. If you vilify, condemn and eternally disparage, why, resign your posi- tion, and when you are outside, damn to your heart's content. But, I pray you. so long as you are a = part of an institution, do not con- demn it. Not that you will injure — the institution — not that — but when you disparage the concern of which you are a part, you disparage your- self. — Elbert Hubbard.

a_thro_away 10y ago

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.

cr0sh 10y ago
> 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).
- a_thro_away 10y ago
  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?

johansch 10y ago

Page 314: Killing Sharks by Electricity