Did the early early pioneers use 'scopes?

[AncientBrit]

Did the early early pioneers use 'scopes?
More importantly were 'scopes commercially available and within their budgets?

Or did widespread use of cathode ray tubes follow later?

Most experiments seemed to have been carried out on subjective observations using a camera/monitor setup.

I can't recall seeing any contemporary photos with a 'scope lurking.
Perhaps I haven't researched hard enough.

Regards,

Graham

[Steve Anderson]

Prior to WWII the 'scope was quite rudimentary often having no amplification or timebases....you had to supply those yourself externally...somehow.

They were often just school or laboratory novelties.

As a result of the development of RADAR these instruments evolved into what we have today. one of the best references to the CRT (in general) is a book by Peter Keller (US, and ex-Tektronix guy) but until I return to my normal residence I don't think I can access it.

I do have a few schematics prior to WWII, mainly from US manufacturers. Hartley and the like, but precious little from Europe. Philips were pre-eminent in this area for many years doing battle with the US based Tektronix.

Other names spring to mind, Servicscope (UK), Heathkit (US), and many others, but they are all predominantly post-war.

RADAR did lead the way...

The attached book (dated 1925) may be of interest...

Steve A.

[AncientBrit]

Thanks Steve.

Then it looks like early TV experimenters would have concentrated on the main task, getting recognisable pictures out of pretty rudimentary gear and not devoting any time to make test/analysis kit.

Cheers,

Graham

[Viewmaster]

There's always Duddell's mechanical oscillograph..
..good up to 300 Hz.
Rather pricey now to buy. A modern double beamer is much cheaper.

[AncientBrit]

Thanks Albert.

But did any of the known TV experimenters use this or something similiar?

Regards,

Graham

[Viewmaster]

Well Graham, the Duddell Oscillograph was being made in 1899 onwards by the Scientific Instrument Co. of Cambridge.

Funnily enough I have just this moment found this out on eBay !! A small advert for sale from the Cambridge Co.
I searched for, 'Duddell Oscillograph' and hey pesto there it was...

http://www.ebay.co.uk/itm/1899-ad-c-dud ... 43a9e1c05d


It is tempting to think that maybe Baird and other early TV experimenters may have bought one in the early 1920's, but we may never know.

[AncientBrit]

Thanks Albert.

Are you tempted to purchase?!

The upper freq response limit of 300Hz would probably make it unsuitable for any NBTV video investigation.

I would suggest a response to say 4kHz would have been needed for early NBTV work.

And phase response?

Cheers,

Graham

[Steve Anderson]

Interesting to note in the attached standards drawing dated November 1935 for Bairds 240-line system that reference is made to an oscillograph. This standard ideally would need a 1MHz bandwidth or thereabouts, of course the 'scope doesn't need that bandwidth for simple 'quick checking', but for any real measurements it would.

The line sync at 8% of line time is approx. 13us, so the instrument couldn't afford to be too lethargic..what was used? No clue.

Steve A.

[AncientBrit]

But an interesting historic pointer all the same Steve.

Well researched,

Regards,

Graham

[Klaas Robers]

I know that in the field of transmitters a kind of oscilloscopes were used. Poulsen used such a contraption to check the wave form of his arc transmitter. This was possible because the currents and voltages were high, so deflection was no problem. I think the "horizontal" deflection was 50 Hz AC. But is was very rudimentary. I read this in a German radio magazine of about 1920. So Poulsen knew the wave form of his transmitter.

On the other hand I recently got a Dutch story of J.J. Numans about the first crystal controlled AM shortwave transmitter (PCJJ) that he built in 1927 in the Philips "NatLab" and I found no link in the the text to whatever form of oscillograph. He also did not mention how he checked the modulation depth, may be just by listening to the demoduated signal.

So in 1927 even at the Philips NatLab, an oscilloscope was unknown.

[AncientBrit]

Thanks Klaas for your research,

Cheers,

Graham

[DrZarkov]

Of course there were galvanometers. German Wikipedia mentions the "Schleifenoszillograph" (loop-oscillograph), made in 1905. This device used a galvanometer with a small mirror on it, a light beam was moved to a photographic paper. This device was usable up to 3 kHz.

The "real" oscilloscope seems to be invented by Cossor in the 1930s.

[Klaas Robers]

Well Volker, in the article in the German magazine of 1920 (or even earlier ?) there was written of a Braunsche Röhre, so a CRT tube. Cathode rays were discovered rather early. I was amazed about it, but they did not have any amplification in it, the deflection plates were tuned wit a coil and the transmitting antenna current was coupled into this coil. And it could work on the 10s of kilohertz, to be even 100 kHz, of the long wave arc transmitters.

The magazine was an earlier version of the "Rundfunktechnische mitteilungen". I also have seen two photographs of the Poldhu station in Cornwall, one with the large antenna that Marconi erected, the second a day after, when they have had some storm and everything went into a great mess. Marconi did not have an educated feeling of mechanic constructions. That magazine was very early in writing about radio, and in a very scientific way.