My dad came home with one of these. A fluoroscope used by shoe salesman.

He used it to set broken bones. Worked really good. In a week we destroyed it. Too dangerous to use.

 

Where I work, we have almost an entire building dedicated to repairing and maintaining things like TWTs, klystrons, vacuum-tube-related devices, and many, many other "antique" technologies we HAVE to support. It's like walking through a museum of obsolete technology when going in those areas, strangely juxtaposed against the (significantly) more modern systems being worked on in the same building. I had never even heard of a klystron until I started there back in June.

 

My dad came home with one of these. A fluoroscope used by shoe salesman.
View attachment 254828
He used it to set broken bones. Worked really good. In a week we destroyed it. Too dangerous to use.

That equipment used Xrays and has been banned in shoe stores for quite a while.
I remember them well.

 

Are klystrons obsolete? It wasn’t so long ago that we used them for high powered microwaves amplifiers.

 

Are klystrons obsolete? It wasn’t so long ago that we used them for high powered microwaves amplifiers.

We still use them for that purpose, though we’re also trying to get more solid-state equivalents (hard task, for the power levels involved). Perhaps “obsolete” wasn’t the most accurate of terms.

Edit: apparently, they’re more widely-used than I thought. They’re a staple in more UHF/EHF high-power systems than I realized.

 

We still use them for that purpose, though we’re also trying to get more solid-state equivalents (hard task, for the power levels involved). Perhaps “obsolete” wasn’t the most accurate of terms.

Edit: apparently, they’re more widely-used than I thought. They’re a staple in more UHF/EHF high-power systems than I realized.

that might be a tall challenge… I wonder if it’s even possible to be more efficient or save weight… might be worth a thought experiment or two

 

that might be a tall challenge… I wonder if it’s even possible to be more efficient or save weight… might be worth a thought experiment or two

That’s one thing we’re trying to figure out, I think. With current technology? Probably not. Though power transistors have come a long way, we are probably still a ways off.

 

That’s one thing we’re trying to figure out, I think. With current technology? Probably not. Though power transistors have come a long way, we are probably still a ways off.

Although GaN, GaAs and SiC are promising, they’re toys compared to what a klystron can do. We are talking about semiconductor conductance vs an electron beam. The cooling and parallel channels required as solid state would be daunting. Also the switch frequency of transistors don’t even come close.

Edit: having said that I wonder if solid state is more robust in the long run and we will reduce the size and weight. They might be easier to tune on the fly and practical frequency is well within their parameters.

 

Bought a house to make a rental. The electricity was done like this. Single wires, some not insulated, in the walls. The junction boxes looked like china dinner plates with a bolt hole in the middle. Two plates bolted together to make a chamber. The wires were soldered together. Not a ground wire anywhere. The first junction box for the entire house had three 10A fuses. (30A total for a large house) Neutrals and Line are reversed in many outlets. Each room had one light bulb and one outlet. Over the years the house was upgraded to 50A and then 100A service. I ripped out the panels and installed a 200A box. There are two kitchens and 7 bead rooms. There are times when the house uses all of 100A. "Know & Tube" wiring.

 

Oh, dear, that's a pretty old house! At that age, at least you probably have copper as it was before aluminum house wiring was in style. I have heard of this kind of wiring but had not see it or a picture of it until now. Thanks for the photo!

 

That is AKA Knob & Tube wiring, it is banned here for may years now and insurance companies are loath to cover the residence.

 

I have never seen that type of wiring except in history books.. I have had to deal with all the issues of cloth wiring

 

Here's one for you younger guys:
In the 1940s all the best radio receivers had a "Magic Eye" tuning indicator. That's the green thing in the picture. The magic eye indicator is a vacuum tube with a conical-shaped target anode coated with zinc-silicate at the end of the glass envelope. The circular display has a darker segment which closes up as negative grid bias is applied.

 

Hello,

There are more types of magic eye tubes:
https://en.wikipedia.org/wiki/Magic_eye_tube
The inline types I have seen in old tape recorders.

Bertus

 

Here's one for you younger guys:
In the 1940s all the best radio receivers had a "Magic Eye" tuning indicator

Us young guys always wondered what the grandfather of software defined radio techniques look like

 

Us young guys always wondered what the grandfather of software defined radio techniques look like

Define young

 

Okay, but you have to promise not to quote me on this.
Those I considered to be young never heard of the EM80 (or alternatively EM84) magic eye vacuum tube.
Got out of that one!

 

What are vacuum tubes?

 

What are vacuum tubes?

The internals operate in a vacuum!
Just as most radio/amplifier valves/tubes do.
As opposed to gas or mercury vapour etc. etc.

 

Hello,

@Wolframore , The wiki has a page on vacuum tubes:
https://en.wikipedia.org/wiki/Vacuum_tube

Bertus