As far as I know radiotubes are still used in space exploration, simply because they can handle the high radiation levels in space much better than semiconductor devices. Furthermore you can often say that analogue technology is much more accurate than digital measuring devices.

Also we still use quite a lot of "old tech" like the fuel cell (invented in 1838), the electric battery (patented 1887), the solar cell (the principle was first discovered in 1839 by Bequerel and the first real solar cell was built in 1893), or the steam turbine in power plants (the principle was already known to Heron of Alexandria) - not to mention the wheel ;)

So, just because the equipment today looks more fancy, the underlying principles or even the devices themselves are older than one may think. Thus our modern world is full of places uses of old technology ;)

Thanks Johannes, yes, some very small radio tubes were manufactured and of course many with multiple tubes inside the same enclosure, e.g. double triodes or triode-tetrodes etc. One can build very functional instruments using vacuum tubes, and as you say, they are more resistant to high radiation levels, electromagnetic pulses, and of course the deadly word for much of the electronics today 'static' electricity. High power transmitters, say as in broadcast transmitters, also use tubes today. Good thing the wheel is still here, it has not yet been replaced by an anti-gravity floater-matter-suspender!

" Is modern and high tech always the way to go in technology?"

No.

There are a great many other parameters to consider. Perhaps you have a hard deadline, a tiny budget, or a limited workforce. Any of these might make you rethink tossing out that old signal generator that (gasp) didn't have a GPIB connector, and which (horrors!) meant that you had to manually turn some knobs.

Latest and fastest isn't always best.

I've often found that the 'equipment graveyard room' in a research department is the most useful room in the whole building.

As for vacuum tubes, yes, TWTAs are used still in many commsats for their power-handling ability and as was rightly pointed out by Ludwig, such non-semiconductor devices aren't physically the toughest but do survive EMP and static exceedingly well.

Hi James, good answer. There are certain older technological applications which just seem to be so much more practical. As example, seeing you mentioned a signal generator, I use a small US Navy Model LM-17 "Crystal Calibrated Frequency Indicating Equipment", which I can use to set either the frequency of a receiver or a transmitter. These have a heterodyne circuit, with a very stable variable oscillator (which can be calibrated against an internal crystal oscillator). If you need to measure the frequency of an external signal then the unit acts as a receiver. You just listen on headphones and zero-beat the heterodyne. I have several of these, and the one I use quite often, I have had with zero maintenance, for 40 years. It was manufactured in the early 1940's. It uses only 3 tubes.

Really old technologies such as the windmill or the charcoal stove will be here to stay, not only in developing countries. but in the West people can use them for special purposes such as when you grill beef on charcoal, which gives a much better taste and aroma. The old quill made from goose feather can be of use too.

But these are very different from the newer old technologies such as the vacuum tubes because today nobody produces the tubes any more. It is just not economical. You need an ecosystem of industries and supplies to produce vacuum tubes for consumer electronics cheaply but those do not exist any more. Whereas you can produce the goose feather quill withou relying on those extensive supply chains.

Thanks Soraj, actually vacuum tubes are still being manufactured, especially tubes used in the audio industry. I am restoring a windpump at the moment, to be used on my farm, so completely agree with you on that type of technology, it is basically everlasting.

Exactly Johannes, "the underlying principles or even the devices themselves are older than one may think"... Fundamental ideas (basic principles) behind devices are immortal as the human soul while their implementations (devices) are mortal like the human body... Great circuit ideas are "non-electrical"; they are not dependent on the specific implementation (tube, transistor, op-amp etc.). We should keep these ideas to recognize them in the new devices... I have created the wikibook Circuit Idea to show the great circuit ideas:

https://en.wikibooks.org/wiki/Circuit_Idea

Hi Cyril, I agree 100% with the philosophy of this. Then there is also the backward reflectance you have to consider, our 'memory circuit' which interacts with old and future concepts. Perhaps this can be described as a standing wave, where the input impedance does not exactly match the output impedance, so there is internal reflectance (the standing wave) from the present to the past. We do technological 'adjustments' (from tubes, to transistors, to MMICs etc.) to reduce the standing wave ratio to meet requirements, requirements of society, technology, the financial system etc. So I can easily jump from 1930 technology to micro-technology, and I do this every day, as I mentally do the circuit match.

Thanks Stefan,  yes the accumulative/non-accumulative progress in science/technology is an interesting facet, my question does have it as a hidden agenda to some extent. I think the van der Pot book will be interesting although heavy reading, partly as I would have to plod through the German (langsam und mit der Schwierigkeit).  Both science and technology are accumulative to some degree,  even if it is just to complete a mental picture of some line of development; it is always easier to understand the present if we know the stages through which a certain branch of science/technology went....it certainly provides one with  a feeling of appreciation, particularly if one evaluates a piece of equipment that was well engineered and well built.

@Stefan, thanks, bought an ex-library copy for $20 on Amazon,  yes Dutch is a bit easier. Thanks for the info!

Hi Georgia

I agree 100%, not only is the documentation important of course but also preservation of samples of these technological achievements,  so that 'the real item" is available to view (and sometimes to study!). Many technological achievements only exist in pictures or documents, these are lost forever.

Hi Stefan, true, in our work we have to include may post-Newtonian 'corrections' to Newtonian mechanics, this is routinely done in space geodetic data analysis, e.g. in satellite laser ranging. The library backup is an interesting point, and one wonders whether there are some 'knowledge repositories' locate in strategic and globally distributed points to protect the inhabitants of Earth against losing valuable information during a major catastrophe.

Hello,

I can think of at least two old technologies that are still being used and investigated today: 1) coherers, and 2) the Welsbach mantle.  

The coherer was the first commercially viable radio detector before the electrolytic detector, the cat whisker diode, the vacuum diode, and the junction semiconductor.  Because of it short time in the spotlight of commercial use, the exact mechanism by which coherers functioned was never explained.  Toward the end of the 20th century mechanical contact detectors called MOM "diodes", similar to coherers, were resurrected for laser heterodyning experiments, though, again no one understood how they worked.  It should also be noted that during the 1950's, at the start of the computer age, coherers were evaluated as potential memory devices.  For a detailed look at all of these applications of coherers, see my 1993 thesis titled "Coherers, a review" on my ResearchGate page.  Several groups in Europe and the United States have been investigating coherer behavior for the last 10 or 15 years, check ResearchGate.  It was the discovery that other people were still investigating coherers that encouraged me to place my thesis on ResearchGate.

The Welsbach mantle, sometimes called the Auer light or gas mantle, has been around for at least 100 years.  While the exact mechanism by which it functions is still not completely understood, the use of the idea of a "selective radiator" has been resurrected in an attempt to make more efficient light sources.

Regards,

Tom Cuff