General thread of obscure old tech

A place to discuss the brutal yellow evil we all love so much.

Moderators: Kent, metasonix

Post Reply
User avatar
metasonix
Tube Pioneer
Posts: 4370
Joined: Fri Aug 03, 2007 2:35 pm

General thread of obscure old tech

Post by metasonix » Fri May 22, 2020 4:39 pm

This is a drop place for non-company related old technology of a weird or unusual nature. Much of this is not available for your amusement on Wikipedia and some of it is completely non-Googleable. Some of this was posted on our Facebook page, this thread is for people who don't use FB.

Below: Amusing 1960 article about troposcatter communications. The "highest quality and reliability" part is funny because tropo was far from trouble-free. Despite being capable of carrying "always on" multi-channel telephone and data links, UHF tropo was extremely wasteful of power--a multi-kilowatt transmitter resulted in nanowatts of signal at the receiver end. In spite of claims about "reliability" it was still noisy and prone to interference from thunderstorms. 2 GHz tropo was alleged to be "better" yet usually ran with megawatt klystron transmitters. Wonder why. (Even seen a megawatt klystron? You'll never forget it.)

The first major tropo network was in Alaska because running cable or microwave links there would have been prohibitively expensive. Another system ran in hops across the Pacific from Hawaii to Okinawa, island to island. Yes, you need multiple gigantic dish antennas at both ends, aimed at the horizon. Plus local infrastructure to run it. A tropo system works but it's costly.

Militaries still use it for field communications when there is no other choice. It has been replaced by microwave multidrop, fiber cable or satellite in the vast majority of applications. I'm told that some hams still experiment with it.
antenna (1960) color.jpg
page-1.jpg
page-2.jpg
page-3.jpg
page-4.jpg
page-5.jpg
You do not have the required permissions to view the files attached to this post.

User avatar
wuff_miggler
Wiggling with Experience
Posts: 468
Joined: Wed Feb 19, 2020 11:11 pm
Location: Disney, Australia

Re: General thread of obscure old tech

Post by wuff_miggler » Fri May 22, 2020 4:46 pm

thanks for posting this Eric!

User avatar
metasonix
Tube Pioneer
Posts: 4370
Joined: Fri Aug 03, 2007 2:35 pm

Re: General thread of obscure old tech

Post by metasonix » Sat May 23, 2020 2:58 am

A discussion of how Hewlett-Packard started (the 200A audio oscillator) brought this from Richard Knoppow:
FWIW, I have two 200A oscillators. Have not tried them in years but one of them worked when I got it. One of them came from the Disney studio long ago. It was used for recording the Fantasound sound track for Fantasia. The original sound track was a steerable six track system using filters in playback to steer the sound to the back of screen speakers. My oscillator has the special frequencies engraved in red on the dial, otherwise its standard. Its been described in detail in several places. Only two theaters were ever set up for it. In Los Angeles it was the Carthay Circle Theater, now demolished and one in New York but I don't remember which. I have seen an original issue Technicolor print but with a standard sound track. When Disneys decided to re-release it some years ago they found the original masters were gone. I also remember some story about transferring recordings via telephone line from San Francisco but don't remember the details. A more recent re-release used completely new recordings. A friend was the music mixer. The recording was done at the scoring stage at CBS Studio Center, originally Republic Pictures. This is a very large stage built in the late 1940s or early 1950s. Described in detail in the SMPTE Journal. A lot of records were recorded there. When I was on the stage and walked it I found it had a back slap. Disney's had a much smaller stage also designed by the same fellow from RCA. It also had a slap. Now converted into something else. I once had friends at Disney but that was long ago, probably all dead now.

The oscillators were sold by Norm Neely, I think -hp-s first large sale. Disney himself earned the enmity of a lot of -hp- people in some anniversary doings by calling the company Packard Bell. I was told this by Norm Neely himself.

User avatar
Yes Powder
Powder that makes you say "Yes"
Posts: 1388
Joined: Thu Sep 03, 2015 2:23 am
Location: Albany, New York
Contact:

Re: General thread of obscure old tech

Post by Yes Powder » Sat May 23, 2020 3:39 am

Cool stuff! :guinness:

User avatar
luchog
Crazy Pony
Posts: 1060
Joined: Sat Nov 21, 2015 2:57 pm
Location: The Emerald City

Re: General thread of obscure old tech

Post by luchog » Sat May 23, 2020 12:28 pm

Interesting bits of history there.

User avatar
bitflip
Ultra Wiggler
Posts: 866
Joined: Sun Dec 14, 2014 10:19 pm
Location: in the series of tubes

Re: General thread of obscure old tech

Post by bitflip » Sat May 23, 2020 12:52 pm

Good old cold war days! These and the Duga and Mickelson radars and facilities are fascinating.

User avatar
metasonix
Tube Pioneer
Posts: 4370
Joined: Fri Aug 03, 2007 2:35 pm

Re: General thread of obscure old tech

Post by metasonix » Sat May 23, 2020 3:45 pm

bitflip wrote:
Sat May 23, 2020 12:52 pm
These and the Duga and Mickelson radars and facilities are fascinating.
Yeah, there's nothing more insane and wasteful than over-the-horizon radar. Uses megawatts of power and enormous antennas, frequently returns false positives from various causes, etc. They never learn the lessons of the past either: the Russians have built a NEW OTH radar system. Mostly to soothe Putin's massive Cold-War-ish ego, apparently. And the Safeguard program was just a total massive waste of money.

BMEWS, the all-American solution, wasn't any less insane. It was notorious for reporting the moon and polar-route airliners as "positive returns". Used the largest klystron tube ever made, the Varian VA842. There was one on display for years at the Fry's Electronics store in Sunnyvale;
va842klystron.jpg
Despite being a 1950s monstrosity, BMEWS was not shut down until 2002. Replaced with far smaller, cheaper, more reliable phased array radars. Certain old men in the Pentagon are still convinced the Commies are coming to eat our babies.
https://www.afspc.af.mil/News/Article-D ... s-is-gone/
You do not have the required permissions to view the files attached to this post.

User avatar
metasonix
Tube Pioneer
Posts: 4370
Joined: Fri Aug 03, 2007 2:35 pm

Re: General thread of obscure old tech

Post by metasonix » Sat May 23, 2020 3:56 pm

As Dan Stocks said on the TCA mailing list
I havent tried this with 12AX7s, but I did try testing a range of 12AU7 and ECC88 in some audio gear a while back. Me & a mate both listening to the setup. Neither of us had any particular expectations, but were curious to see if there was anything to it. Both of us noted subtle, but quite noticeable differences between different types/brands. The effect is most pronounced in circuits where there is no NFB going on, feedback tends to really diminish any differences
My response:
Which is exactly the conclusion I reached while doing those "shootout" tests for VTV long ago. Audiophools make a great hue and cry about the vast differences, but they are actually quite subtle. Such listening tests are extremely tedious and unpleasant so it's easy to understand why serious comparison testing is rarely done.

Another thing I discovered: the best sounding tubes usually also had the lowest signal distortion and thus the best average manufacturing tolerances and quality control. 12AX7s are all over the place in distortion figures though the usual vintage ones that bring high prices (Telefunken and Mullard ECC83s) tend to do best on the test bench. Cathode coating quality also has an effect--better transient emission means slightly better sound. The more fanatical 'philes still refuse to believe any of this. Putting it down to "vintage magic" is easier and allows the arrogant fools who run audiophile magazines to set themselves up as "arbiters of quality".

You know what glass power tube (that I tested anyway) usually has the lowest signal distortion without feedback? The 300B. The 845 is in the same ballpark, though it's more difficult to use, needing higher voltages. There is a reason for the fanatical following 300Bs have/suffer from.

I've said all this before but it bears repeating. There is a new generation of audio "bugs" who are just as ignorant and arrogant as their predecessors--they will relearn the same old things.

User avatar
metasonix
Tube Pioneer
Posts: 4370
Joined: Fri Aug 03, 2007 2:35 pm

Re: General thread of obscure old tech

Post by metasonix » Sun May 24, 2020 10:41 pm

I've got a REALLY rare photo for you....it was not easy to find. This is the so-called "Kiwi-TNT" test at the Nevada Test Site in January 1965. After testing was finished on a KIWI-A nuclear thermal rocket engine for the NERVA program, It was decided to perform a safety test by "excursion" of the engine via a "prompt critical" reaction. All safety controls were disabled and the control rods were fully withdrawn. Even though the engine was not designed to explode, it did--releasing something like 10 terawatts of power. Bits of the engine were found 2000 feet away.

I suspect this color photo is difficult to find because the DOE doesn't want people to get the "wrong idea" about the NERVA program. It was a serious and successful attempt to design a working nuclear-thermal rocket engine that could be used in the space program. Unfortunately, to get the high specific impulse such engines could manage (twice as high as any chemical rocket), one has to run the reactor core at temperatures not far away from melting. It just wasn't worth the extra effort and cost. So everything is still being done with chemical rockets.
kiwi.gif
You do not have the required permissions to view the files attached to this post.

Post Reply

Return to “Metasonix”