[albertgen]

Are those copper Mershon capacitors available anywhere? I bought a Philco 90 to restore and it looks like someone took them out and replaced with aluminum ones. I would like to find a pair of these. Thank you, Al

[morzh]

Yes they are sometimes sold on eBay. Or maybe you buy a junk chassis that has them. A 70 chassis is likely to have them.

http://www.ebay.com/itm/Philco-Model-70-...541b6e8866
Like this one. really dirty. But a Mershon.

[albertgen]

Thank you Morzh!, Al

[klondike98]

Welcome to the Phorum!! Yep, they do come up on Ebay from time to time. Save a search for them and it can alert you when they appear. I picked up two a few months back.

[Arran]

 I'm not sure about model 90s but some of the model 70s used Sprague filter caps from the factory, if those are not aluminum they are plated with something to make them a silver colour. If push comes to shove, and you really want copper filter cans, you can make some fake Mershons out of a selection of plumbing parts, a short length of copper pipe of the appropriate diameter, a matching pipe cap, and either a brass or plastic threaded nipple for the base.
Regards
Arran

[Ron Ramirez]

I've seen one or two of the Spragues - the ones that passed through here were nickel plated over copper. I only know that because some of the nickel had worn, revealing the copper underneath.

[morzh]

I think inside those nickel plated copper caps were practically Mershons, as inside they are the same plus using liquid electrolite. Likely Sprague first simply copied Mershon technology (or acquired it).

[Arran]

I think inside those nickel plated copper caps were practically Mershons, as inside they are the same plus using liquid electrolite. Likely Sprague first simply copied Mershon technology (or acquired it).

Mike;
  All of those wet electrolytics are designed in a similar manner, only differing in terms of the anode plate design inside the capacitor can. What I was trying to point out is that not all of the 1931 BabyGrand models used copper can wet electrolytics made by Mershon, some used Sprague cans. If a model 90 does not have a pair of copper Mershon filter capacitor cans does not mean that they were not original to the set, Mershon caps were OEM but so were those nickel plated Sprague cans.
 The story I read is that the wet electrolytic capacitor was invented by a Ralph Mershon, so it's very likely that he and his company not only produced wet electrolytic cans but also licensed other manufacturers to produce similar cans, perhaps Sprague had such a license? Then again it may have been along the lines of skirting Edison's patents on a light bulb, like where Reginald Fessenden reworked the filament structure inside a lightbulb so Westinghouse could manufacture them. Maybe all that had to do was change the anode design, materials used, shape, electrolyte formula, or the shape of the can, and Ralph would not have had any say?
Regards
Arran

[Alan Douglas]

Mershon had most of the patents (not all) but Amrad was the licensed manufacturer. That division was sold to Magnavox in Ft. Wayne. Presumably Magnavox licensed Sprague.

I'm not aware that Fessenden had anything to do with electric lamps after leaving Edison's employ in the 1880s.

[Arran]

Mershon had most of the patents (not all) but Amrad was the licensed manufacturer. That division was sold to Magnavox in Ft. Wayne.  Presumably Magnavox licensed Sprague.

I'm not aware that Fessenden had anything to do with electric lamps after leaving Edison's employ in the 1880s.

 It was in a biography I read years ago called "Radio's First Voice, The Reginald Fessenden Story" or something similar to that. No doubt that it has some errors in it such as the Christmas Eve broadcast story, but Westinghouse did have a habit of hiring former Edison employees. It also said that he had some involvement with the hydroelectric development at Niagara Falls in various ways, but given the pioneering nature of that they probably hired scores of engineers and scientists.
Regards
arran

[morzh]

Fessenden was very talented and his interest was all around.
He invented sonar, AM detectors of several types (thermal, chemical), aside from being the creator of CW transmission.

[mikethedruid]

in The Complete Radio Book by Raymond Francis Yates and Louis Gerard Pacent, published in 1922 by the Century Company, it has the following note on Fessenden in the chapter "Who's Who in Radio" :

REGINALD AUBREY FESSENDEN
Reginald Aubrey Fessenden was inspecting engineer to the Edison Co. at New York in 1886. He took up teaching work and conducted classes in physics and electrical engineering at Western University in 1892, became professor of electrical engineering at Western University, Philadelphia, in 1893, and became special agent to the United States Weather Beaurea in 1900. He has devoted much attention to a system of wireless tellegraphy known by his name, and has also carried out important experiments involving wireless telephony. He has been a contributor of articles on wireless telegraphy and telephony to many technical journals. He was born at Milton, Canada, in 1866, and was educated at New York and Port Hope, Canada.

More can be found about this very interesting man on this web page and by following links from there : http://www.radiocom.net/Fessenden/

[morzh]

I'd say go either to an article published, I think, in IEEE several years ago, a great article with many details about him developing his CW, including the generator, or go to Wikipedia, whose article on him is not bad either.

But he was a phenomenal guy.
And even though he reaped little from his inventions (RCA settled with him for enough money for him to comfortably live in the estate he bought) I think one of the sweetest revenge moments on his rivals like Marconi, who laughed at him, was when Marconi had to buy the license from him for CW, therby admitting defeat.

[Arran]

I'd say go either to an article published, I think, in IEEE several years ago, a great article with many details about him developing his CW, including the generator, or go to Wikipedia, whose article on him is not bad either.

But he was a phenomenal guy.
And even though he reaped little from his inventions (RCA settled with him for enough money for him to comfortably live in the estate he bought) I think one of the sweetest revenge moments on his rivals like Marconi, who laughed at him, was when Marconi had to buy the license from him for CW, therby admitting defeat.

 He had judgements and made settlements made with a number of big names of the era, including Lee DeForest, unlike Deforest though Fessenden, as you say, never ended up broke. I have more respect for Deforest then Marconi though, Marconi was basically just a tinkerer with some connections in the British government through his mother, whereas Deforest, as litigious as he was, was a fairly earnest researcher and experimenter into various notions for improved wireless detectors when he stumbled across the triode, what he called an "Audion". He even made his Audions available to radio amateurs and experimenters before he nailed down some contracts with the U.S Navy.
 What many people don't realize is that Fessenden held literally hundreds of patents, 350-400 or so by the time he was through, including some very important ones, but his name was never recited off by school children, nor was he given any heroic fanfare in movies. The difference being is that Tom Edison invented the phonograph, and bought the rights to the incandescent light bulb from Woodward and Evans (no I am not making that up), then credit was given to him for inventing it. As the guy on the street what a light bulb or phonograph is, they know, ask them what continuous wave or heterodyning is then they would not.
Regards
Arran

[Ron Ramirez]

Well, I don't have much respect for de Forest. He did invent the audion (triode vacuum tube), but didn't really understand how it worked. Armstrong did, and put it to work with his regeneration patent. de Forest somehow came up with the idea that he was the true inventor of regeneration and, after several court cases, finally found a court sympathetic to his cause which unjustly cost Armstrong his first great invention.

Then de Forest teamed up with Theodore Case to research sound-on-film technology. Case was the true inventor here while de Forest took all of the credit. Case eventually broke ties with de Forest and went on to perfect his sound-on-film technology, which he sold to Fox.

According to Ken Burns' Empire of the Air documentary, an arrangement was once made to send a postcard to de Forest as a publicity stunt, addressed only to "The Father of Radio, (I believe) Hollywood, California." The postcard was sent back, marked "Addressee unknown."

Edit: I almost forgot - One of de Forest's "inventions", the spade detector, infringed upon the patents of Fessenden's electrolytic detector. Fessenden sued, and unlike Armstrong, he won.