Capacitors

[Axmanjr]

What is a silver mica cap?  And what is a metal film? I couldn't find either of them @ my electronics store?  Instead, the store had a bunch of ceramic, electrolytic, mylar/film caps.

I also found cap values of 47Mf and the like.  Isn't an Mf= mega farad?  I thought that capacitors valued over 1 farad was only used in nuclear bombs- or something like that. :?   Well, anyways... I had a very difficult time finding parts for my next build...

[Peter Snowberg]

Silver/mica caps are made by alternating layers of silver and mica insulator. They're free of piezoelectric effects which makes them really great in tube amps, but in addition they're always epoxy coated and non-porous so they don't absorb moisture like most ceramic caps. All around cool caps.

Metal/film caps are made either by wrapping layers of foil and a plastic film (like Mylar, a.k.a. polyester), or by coating the plastic film with a layer of metal film in the same way aluminum colored mlar balloons are made. There are lots of types of plastic film so they're often named by the film type. Also great caps.

I also found cap values of 47Mf and the like.  Isn't an Mf= mega farad?  I thought that capacitors valued over 1 farad was only used in nuclear bombs- or something like that. :?

I think it's safe to say we'll never see a 47 mega-farad cap. If you use two metal plates spaced 1/4 inch apart, a single farad cap would require 6 square miles of plate area. :shock: You will see 47 nano-farad caps all the time in effects (0.047uF) so make sure it's not an N rather than an M. The best way to state micro-farads is with the Greek letter that looks like a lowercase 'u', but since that's not too common to find on typewriters sometimes people will use an 'm' instead. You can spot the value there by size and type. If you see a fairly small film cap, it's going to be 47nF. If it's an electrolytic (in a can), it's probably going to be 47uF unless it's really, really tiny.

I've never seen the guts of a nuke, but the caps you would find there are going to be smaller. In that case they're high voltage but less than 10uF for sure. The detonating system works by dumping the caps into a detonator very quickly so a small cap at high voltage would be called for. Now the type of cap.... Those would be some good caps for tube amp use. The high dump speed requires super low inductance. If you want similar caps, look at caps made for RADAR and other pulse applications. Check out the "fastcaps" at http://www.angela.com

Go back and get the mylars and put up with the ceramics where you can't find mylars of the required value. These days I get most of my silver/mica and mylar film caps from http://www.circuitspecialists.com

Take care,
-Peter

[bobbletrox]

I've been getting into experimenting with different cap types thanks to the information you've been posting Peter.  I'm currently making a bass fuss with Polypropylene caps to see how it sounds.  I'll post a pic of the PCB when I'm done!  

I'll have to give those mylar caps a try too at some stage.

[blabj]

I've never seen the guts of a nuke... The detonating system works by dumping the caps into a detonator very quickly so a small cap at high voltage would be called for.

thank god you havent seen inside one, you seen to know a little too much  :?
only joking man
callum

[Peter Snowberg]

I spent a lot of time repairing and restoring some nuclear surface to air missiles for the United States National Park Service.

More than anything, I think I did this out public service and to administer self-therapy after being scared S#($less about how close the "superpowers" were to killing the planet during the 70s and 80s.


This is a Nike Hercules MIM-14B missile being raised into launch position. The missile is 41 feet long, hits a max speed of mach 3.65, goes 90+ miles, reaches over 100,000 feet of altitude, and can carry a 40Kt boosted fission weapon designated as the W-31. That was a sized reduced version (30 inch diameter) of the "fat man" bomb that destroyed Nagasaki, but with twice the explosive output. Roughly the equivalent of 80 million pounds of TNT :cry:

This is site SF-88. Just up the road, site SF-93 in San Rafael where I am now almost nuked a Boeing 707 returning from Hawaii with tourists in 1968. Electrical problems on the plane disabled its radio and IFF (Identification Friend or Foe) transponder. An equipment malfunction was the only thing that prevented a launch. The Battery Commander DID hit the launch switch. :shock:  :cry:


Another shot of a missile on the elevator coming up from the underground storage magazine. I used to give a lot of tours there and when bringing a group down into the magazine on the elevator my standard line was, "This will probably be the one time in your lives that you will be asked to hold onto a nuclear missile for safety."  


This is a view into a conventional warhead section sitting in a shipping container, but the nuke used the same exterior packaging because it was part of the missile skin. It also used the same shipping container. No, we did not have any real warheads, but there is a US Army training video take that shows the bomb casing without the missile skin.


This is the LOPAR RADAR screen that was used for target designation. This RADAR put out 1.25 MEGA-Watts and could see about 200 miles. The target designation control is off the frame to the right. I was actually able to fix the system to the point where we actually had sweep onthe scope. There were three transistors in the whole system (part of an interference filter) and a few hundred tubes. The network that connected these missile bases and USAF RADARs together was the first transcontinental digital network while the local connects to that net were a different analog network. I consider this hardware to be the real birth of the internet.


This is one of the cards from a missile guidance section, which was really a radio receiver that understands three commands… pitch, yaw, and go boom. All the guidance was provided by a big vacuum tube computer on the ground and transmitted to the missile via the tracking RADAR. Notice the three small vacuum tubes from the same general family as the ZVex nano-head. There were a bunch of tiny tubes in there.

I was going to build tube amps out of them, but Zachary beat me to it! I would have had something on the market at least a year before the nano-head was announced, but I didn't have the cash at the time and became a Federal employee instead.  :cry:  :cry:  :lol:  :cry:  :cry: My little tube amp design was based on the vacuum tube op-amps in the guadance computer. I love tubes. I actually went to the site to find out more about the tube op-amps and somebody said, "do you want to repair the guidance system?"


This collage has the RADAR and guidance equipment "vans" in the lower left hand corner that I spent over 500 hours restoring. The group at the top left is a bunch of nuclear weapon scientists on a special tour that we do once a year, and the circular thing in the bottom-middle shows the end view of the missile guidance receiver. You can see the edges of the cards like the one above.


On the left is retired Ranger Cathy Petrik who's job I took over for a couple months when she left. On the right is Nike site manager John Porter. Between them you can see a giant servo driven pot with a whole bunch of wire-wound elements that did the Sine/Cosine vector conversions for calculating guidance commands. There were 11 of these servo-pot gizmos in the system. Strangely enough, the design of this device was originally for a phone system testing chart recorder at Bell Labs. The designer had a dream about it being used by an anti-aircraft missile battery outside London during WWII. Very quickly the system was adapted to control anti-aircraft artillery and it worked so well that it was used in the missile system as well.

Yes, as frightening as it may be, I am a former badge-wearing Federal Officer. At least it was just a Park Ranger. When I was a Ranger, I ran this visitor center....

....and the volunteer program at this lighthouse at Pt. Bonita:


If you want to visit, here is the map of the Marin Headlands:


I took all the photos except for the lighthouse and visitor center shots and I did the map & FAQ on the government web site.

For more information:
http://www.nps.gov/goga/mahe/nike/
http://www.nps.gov/goga/mahe/

In addition to working there, I put over 1500 hours of volunteer time in. Now I volunteer here and at http://www.giantstepsriding.org .

Take care,
-Peter  (a.k.a. Ranger Snowypaws :lol: don't ask)

[smoguzbenjamin]

Nukes are scary stuff. Whatabout Bush's new mini-nukes, they're supposed to be twice as powerful as the fat man but then tiny :shock: I'm scared s***less that someday an idiot withan IQ of 65 will be around the White House and decide to nuke the middle-east :shock:

Nasty stuff, nuclear weapons. Why not build tube amps and stompboxes instead?

[Arno van der Heijden]

I'm scared s***less that someday an idiot withan IQ of 65 will be around the White House and decide to nuke the middle-east

I guess that would be George W. Bush...

[smoguzbenjamin]

I was thinking of saying that but decided against that in case I triggered a huge political discussion

[Axmanjr]

Thanks Peter!

I looked carefully at the caps and thought that it was a capital M.  But now that I think about it, everything was in capital letters.... so....

But I also saw "u", which is micro.  But I'll look into it again.

[Peter Snowberg]

I'm just curious if the "M" had legs that were turned inwards at the base and a thin square around it? If so it would be a Matsushita logo.

Take care,
-Peter

[Samuel]

This is a Nike Hercules MIM-14B missile being raised into launch position. The missile is 41 feet long, hits a max speed of mach 3.65, goes 90+ miles, reaches over 100,000 feet of altitude, and can carry a 40Kt boosted fission weapon designated as the W-31. That was a sized reduced version (30 inch diameter) of the "fat man" bomb that destroyed Nagasaki, but with twice the explosive output. Roughly the equivalent of 80 million pounds of TNT

Um, would there be a big call for delivering that kind of payload to something only 90 miles away? I guess if it were surface to air that makes more sense....

[bobbletrox]

Only a 90 mile range?  Geez, you wouldn't want the wind to be blowing back in your direction or you'd be copping the fallout.

Ever heard of the nuclear grenade?  The soldier had to dig a trench to jump into as soon as he threw it...no joke!

[DaveTV]

Great post, Peter. Fascinating--and chilling--stuff.

I used to volunteer over in the Marin Headlands at the Marine Mammal Center during the early 90's. If I'm not mistaken, that whole facility was built on what used to be a missile site. Do you know which site number that was?

I remember there being two underground missile magazines there, like the one shown in your photo. Both were being used to store medical supplies for the seals and sea lions. There was also a door leading into one of the magazines that had been painted with pictures of eagles and missiles flying and the American flag and the words "We Keep the Peace".

There was even a guy there who ended up living in one of the magazines. I guess he didn't have any family or anything and decided he could be useful as a 24-hour security guard, so he built a little apartment down there and lived in it with his cat.

[Peter Snowberg]

Starting out, I just want to say that I'm a total pacifist and I think this stuff is beyond insane. :? :cry:

Only a 90 mile range?  Geez, you wouldn't want the wind to be blowing back in your direction or you'd be copping the fallout.

Ever heard of the nuclear grenade?  The soldier had to dig a trench to jump into as soon as he threw it...no joke!

At the time the military was enamored with nukes and there were 145 of these bases with nuclear capacity built around U.S. cities and factories. Each base had between 10 and 20 nuclear armed missiles. The warhead came in three yields, 2Kt, 20Kt, and 40Kt. A typical base with two missile magazines had two conventional warheads, two 40Kt, two 20Kt, and six 2Kt equipped missiles.

At the time, the USSR had a bomb called the “Tzar Bomba” that was configurable up to 100 MEGA tons. The largest nuke test ever was one of these devices at 1/2 power. If the choice came down to loosing a city and all of it’s suburbs or contaminating the city, the contamination was chosen. The W-31 used all uranium rather than plutonium for this reason.

The Army wanted to achieve a “weapons kill” rather than just disabling a plane. It should be noted that the RADAR operators at SF-88 were watching Russian planes go up and down the coast two to three times a week at 25 miles out, just on the edge of international air space. The U.S. was doing exactly the same thing to the U.S.S.R. except we had a raving lunatic in charge of things by the name of Gen. Curt LeMay. He was inspiration for two of the most insane characters in the movie “Dr. Strangelove” (starring Peter Sellers, and very worth watching). LeMay tried to start WWIII on a number of occasions. :cry: :cry: :cry:

The closest that the U.S. got to a nuclear grenade was the M388 which was more commonly known at the “Davy Crockett”. This was a “nuclear bazooka”. The W-54 warhead on those weighed just over 50 pounds, was about 11 inches in diameter, and put out the equivilent of roughly 500,000 pounds of TNT :shock:. The Colonel that was in charge of the SF-88 restoration was the first commander to be in charge of these weapons in the field. I asked him what he thought of the system and he said, “A million dollar warhead on a 37 cent launcher!” He said that in one of the first demos for the brass, a launcher fell over by it’s self as it broke with nobody standing near it. The procedure for firing was to find a firing point, dig a six foot fox hole, aim the weapon, fire the built-in 30mm tracer charge for aiming, fire the weapon, and quickly jump in the foxhole. The launcher could not take the firing crew out of harms range. That’s military intelligence for you.

A Google image search turned up this page with a bunch of photos: http://www.guntruck.com/DavyCrockett.html

There was a nuclear torpedo that suffered the same problem. There were also a number of 155mm nuclear artillery shells and some much larger ones. Those with file sharing software who want to should look for a 8.8meg MPEG called “Atomic Annie test” to see the largest of these shells.

I used to volunteer over in the Marin Headlands at the Marine Mammal Center during the early 90's. If I'm not mistaken, that whole facility was built on what used to be a missile site. Do you know which site number that was?

I remember there being two underground missile magazines there, like the one shown in your photo. Both were being used to store medical supplies for the seals and sea lions. There was also a door leading into one of the magazines that had been painted with pictures of eagles and missiles flying and the American flag and the words "We Keep the Peace".

I started volunteering in the Headlands at The Marine Mammal Center too and put in their first network in 1990. That facility is built on the remains of SF-89. The hill above the MMC (Hill 88 ) was home to the IFC (Integrated Fire Control, the RADAR and command point) of SF-88. The IFC for SF-89 was Hawk Hill, the highest point on Conzelman Dr. and one of the best Golden Gate Bridge overlooks. The old tracking RADAR pads are still up there. One of the former commanders of SF-89 came to SF-88 one afternoon saying, “I just went to my old base and there were SEALS EVERYWHERE!” :lol: I think that means we won!

Look familiar?


The sound of the magazine doors opening at SF-88 was also used in the movie Star Wars.

One more piece of useless trivia… Remember that old 70s video game Missile Command? That was actually patterned after the console that was used at the AADCP to tell Nike batteries which target to engage (Army Air Defense Command Post, or regional control center. In this case “Air Force Station Mill Valley” on top of Mt. Tamalpais, a.k.a. SF-90DC to the Army ARADCOM people). It used a trackball to move a cursor and then up to 16 buttons to assign the targets to up to 16 Nike sites. The main difference (besides being a game) was that the game had only three designate buttons.

Other Nike sites have been turned into homes, workshops, and schools. I am not sorry to see them converted.

For anybody who wants to know if there was a Nike base near your city, look here: http://ed-thelen.org/loc.html and for more info including anything you ever wanted to know about the system and more, Goto Ed Thelen's home page http://ed-thelen.org/ . Ed is a funny guy and VERY VERY bright. I see him as the R.G. Keen of the Nike world in some ways.

What amazes me most is that major aspects of technology today were either directly the result of, or direct decendants of technology developed for this missile system. Dopplar weather RADAR is a prime example.

If anybody wants to see a really cool tube op-amp look at this: http://www.ed-thelen.org/dc_amp.gif It's like a high voltage (500 volt) TL072 done in tubes, however the slew rate is quite low because of the application. For more see: http://ed-thelen.org/diagrams.html

Take care,
-Peter

[DaveTV]

Yep, that's the place! Great photos, Peter. The Marin Headlands is such a beautiful place. Whenever friends come from out of town, I always take them over there for the fantastic views, especially from the Point Bonita light house. I could totally understand why you'd want to spend so much time working in such a scenic location.

For non-Bay Area people I should point out that Marin Headlands are immediately on the other side of the Golden Gate bridge, opposite San Francisco (I guess the map shows that). The locations in these photos are literally minutes from the Golden Gate Bridge. I sometimes find it hard to believe we have all of this beautiful open space so close to such a dense metropolitan area. I also find it hard to believe that this beautiful land used to house some pretty scary military equipment.

[bobbletrox]

That's an interesting read Peter.  I don't know how people could feel comfortable going about their everyday lives knowing that the world was on the edge of a nuclear appocolypse.  I'm glad I was too young to realise what was going on!

Now, if only those Communists would stop trying to steal my vital bodily fluids  

[Axmanjr]

:shock: WOW, what kind of discussion have I started?  I was just being a little over exaggerant about the whole nuke thing...BUT those pics were pretty nifty!

[smoguzbenjamin]

Hey Peter, why is the US military using tubes? Isn't that extremely expensive and inefficient, or are they not using semiconductors because of possible EMP from a nuke?

[Peter Snowberg]

You never can tell what's going to happen around here. :razz:

Sorry for hijacking your thread Axmanjr.

I did find out a little more about the firing set caps. They’re either ceramic (new ones) or mylar film, and they’re HV with old designs being between 10 and 100uF and new ones being 0.1uF @ 3KV at least for one design.

I got these images from a google search: (the red square is the cap, notice the big leads for low inductance)

 

The last picture shows the buggers at actually go boom. If you ever see what looks like a metal can transistor with an odd lead arrangement and a marking of EG&G on the top, be really careful.

The mylar caps are pictured in this 3+ meg PDF . (BIG file. see section 73 on page 33 & 34)


Ben,
This system is quite obsolete. Engineering started during WWII, the first version was deployed in 1954, and the nuclear upgrade was deployed in 1957. The base I pictured above was one of the last to be closed in the U.S. and that was 1974. Most of them were phased out in 1968 and 1971. Now SF-88 is just a museum run by the U.S. National Park Service.

Transistors at the time were more of a laboratory curiosity and not ready for wide-scale use. When they did become available and consistent, the EMP resistance of tubes did keep them in use so you are correct. The system was eventually upgraded to use a DEC PDP-11 in place of the tube computer. The Royal Dutch Air Force ran sites in Germany from the 60s to the 80s I believe. Today only Turkey, Greece, and South Korea use the system. (last I checked)



OK.... insane stuff done. All pics I post in the future will be pedal related. :lol: (well... most at least, but no more missiles )

Here's wishing for world peace,
-Peter

[smoguzbenjamin]

No nukes!