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Mershon copper capacitors
#16

One of the things that impressed me the most was, (and it was not really one of his imajor nventions per se) when he realized that for CW he needed a high frequency generator, and the mechanical ones got to about 10kc, he ordered one from GE, and they sent him one that he sent back, as it was not any better thsn the rest. Their engineer, Alexanderson, spent almost two years trying to improve upon Tesla generator and, according to Fessenden's note, was not usable and was not much different from Tesla generator at all. This was September 1906.
Then he modded a generator himself and in November (!!! - in two months) he had a working machine that gave him 50-90kc frequency, which he used in his Brant Rock station.


Interesting that after a while this same machine, with increased size and power of 200kW was being sold by GE as "Alexandersson's generator". Really?

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#17

(03-30-2015, 05:36 AM)Ron Ramirez Wrote:  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." Icon_lol

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.

Ron;
  I found out later that Empire of The Air was somewhat of a hatchet job on Lee Deforest, there is a special addition of Radio Craft from the 1940s that tells the story of what was involved in the development of the Audion, it was definitely not a case of Deforest simply grabbing a Fleming valve one morning and deciding to stuff a grid into it. What's more it mentioned all of the other people involved such as McCandless, who later went on to work for Westinghouse.
I know it may make for good entertainment portraying white hats and black hats in a story like this, Armstrong, the hero in the white hat, Deforest, the hustler, and David Sarnoff as the Darth Vader of the story, but what seems like black and white was closer to being on the grey side.

Regards
Arran
#18

It's all gray, never as simple as books make it out to be.

Ormond Raby does claim that Fessenden designed lead-in wires for lamps that Westinghouse used later. It's possible, but you can't use that book as a source for anything because Raby has invented all the dialog in it without citing any sources. It's more like a novel than a history. Raby does claim to have read many of Fessenden's publications and no doubt he did, but other than saying there were many of them, he doesn't provide a list.

The GE alternator was Steinmetz' design; Alexanderson didn't enter the picture until later. As I recall reading, Fessenden and Alexanderson both contributed to the designs used at Brant Rock, but the subsequent development into the 200kW commercial models was largely Alexanderson's work. There are several pages on the Brant Rock models in Alexanderson's biography (James Brittain, 1992).
#19

...Speaking of gray... And to revive this old thread:

<In my best Jerry Seinfeld voice> "What's the deal with all this Mershon Madness?"

Admittedly, I'm new to the classic Cathedrals, having just refurbished my first 70 after doing the 1940's Bakelites for a while before hitting the "hard stuff".

Yes, I restuffed the Bakelite capacitor blocks, but no, I didn't fill them with anything to replace the tar. Yet, there are my electrolytics dangling under the original caps, because I didn't restuff the originals.

Back to Mershon capacitors: I see just as many if not more Philcos (70s and 90s in particular) with plain aluminum or nickel plated Sprague capacitors, and I believe they were built that way originally. Are people pulling out the original capacitors, condemning them as "replacements" or "fakes" and not only driving up the cost of Mershons but also getting rid of the original Spragues that some of us would gladly accept for our "castrated" chassis?

How many of us think the only "correct" capacitor in a Philco Cathedral is a bright copper Mershon? (I've seen a pair of Mershons on eBay asking more than I paid for a whole 70 chassis and speaker wrapped in the tattered plywood that used to be the cabinet! But it had Spragues not Mershons, and I'll keep the Spragues, thank you very much.)

As for me, yes I'm glad when I acquire a Philco with Mershons (The one I just got working), but if it comes with Spragues, I leave them in, and would rather have that than Mershons that came from another radio, or another build of the same model. How many people look in the back of a playing radio to see if it has Mershons?

I wonder how many people out there just think every Philco 70 or 90 or whatever should come with the copper Mershon capacitors, not knowing that those Spragues are original. Maybe for a joke, the next Hippo I find, I'll stick a little Mershon cap in there to drive people crazy. ("Actually only the earliest 1946 Code 121 had Mershons. You're lucky to find this baby!")

Oh: and I left my Mershons with all the patina of a well circulated penny because you can clean them up any time, but the patina is only original once!

Anyway, I know this was a rant (hopefully a little humorous), but the point is, let's not pull out perfectly original Spragues just because we want those copper Mershons in there. If you do pull Spragues, at least save them for those of us who need to fill holes left in the 40s and 50s by well meaning radio techs. Put them on eBay for cheap ($5 to $10 each is probably plenty fair), so someone who spent all his money on a 70 with one Sprague and one hole (or two holes) can fill the hole with something correct.

Livin' on Zenith, Atwater Kent and Philco
All a friend can say is "Ain't it a shame"




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