Recommend me an Oscilloscope

[JonW]

Hey Les, I bet you would be like this guy!
Valve Scope

[top204]

Thanks Jon. A man after my own heart in the video. :-)

I made a valve based oscilloscope when I was about 14 year old. Well.... I took over from dad's building of the scope that he never finished from the 1960s. :-) It was the standard L shaped aluminium chassis with toggle switches and knobs and a beautiful 3BP1 CRT, with EC type triode valves for the X and Y stages, and painted in the classic blue hammerite by dad all of those previous years ago. As a little boy, I remember using the same scope chassis in my bedroom as a front console for a space adventure game I used to play, with all of its toggle switches and knobs, but was far too young to know what it was or get it working. It was just a wonderful technical object. It was never powered up though. :-) I remember dad cut off the mains cable because he knew I would probably plug it in, in my bedroom. LOL. Wonderful memories. :-)

Then, when I was about 17 year old I made my own transistor oscilloscope based upon a Babani book's circuits. With MJE340 transistors for the high voltage outputs. Since I was a little boy, I have had a fascination with Cathode Ray Tubes, and dad helped me understand them. I even got a very old 3" B/W projection CRT working that dad had had lying around in the shed for about 20 years, when I was about 16 years old! I still remember, even dad was surprised I got it working with no diagrams or pin layouts etc. Just an EHT voltage transformer I made and a few resistors and pots in series for the anodes and grid, for focus and brightness. And an old set of scan coils for the X and Y that were huge compared to the tube itself, but worked.

Many thanks to Charlie, who sent me a lovely 3" CRT and a few valves a few years ago, so I can have a go at making another scope when I get my workshop up and running.

Heck, I even made my own rotating disk camera and receiver from 12" LPs and an old selenium cell tube and neon tube I found in the shed, when I was a young-un. I still remember asking dad what the selenium tube was for when I was a little boy.

It's amazing what we remember from the long distant past, when the emotions the memories bring back are good. :-)

Question 1.... What was the first circuit or project you ever built, and when?

Question 2... What was the circuit or project that you are most proud of building on your own?

It's always a good feeling to read what friends have accomplished in their past, because it shows how much we all have in common.

[Giuseppe MPO]

I ordered a B-grade MSO5204 from Telonic.co.uk (refurbished with latest firmware and 2 year warranty) and got a further 10% off a nearly new unit. Total price was £1300 + tax.

Excellent purchase, an instrument with excellent performance, with 4 channels it can decode, without adding external options, almost all the interfaces I need.
With an 8GSa sample rate, it's great in that price range

[JonW]

Question 1.... What was the first circuit or project you ever built, and when?

1986 built a self-oscillating Mixer FM transmitter using a single BJT.

Question 2... What was the circuit or project that you are most proud of building on your own?

This has to be the Reverse band LNB I designed for Direct TV in 2010 in the USA for Probrand International. We were up against really big companies with design teams in the hundreds, and we were two guys plus one mechanical, I was doing all the Microwave, RF, Analog, Digital, DC and Processor work incl all the simulation, layout, and my team member was doing the Feed design and the test plans etc. It was a monumental task as we had three separate dual polarity feed horns, two at extended Ka 17.3 to 20.2GHz and the other at Ku 11.7 to 12.2GHz covering 3 orbital slots.  These all had to be downconverted and diplexed into 4 x 300 - 2350MHz bands (there are 3 feeds with 2 pols, so over 8GHz of bandwidth to process).  These were digitised by 4 x 5.4G/S ADC's and processed in a monster asic then recombined into 24 programmable channels that could access any input and any frequency, in any band and its all digitised with a single 10G/s DAC back into RF in 300 - 2350MHz.  The Asics we used were custom and even today the technology is deemed state of the art.  It took us close to 2 years to develop and is still in production, we recon there are over 10M built.  All for TV!!
I'll see if I can dig out the cad file of the main  Microwave PCB, it's a work of art.  The Microwave portion is all discrete, LNA, Active mixers, DRO, Multipliers etc.  This is a lost art now as many of the devices are EOL and will never be manufactured again:  A real shame

J

[JonW]

Heck, I even made my own rotating disk camera and receiver from 12" LPs and an old selenium cell tube and neon tube I found in the shed, when I was a young-un. I still remember asking dad what the selenium tube was for when I was a little boy.


Lost art Les. My rickety 8563, 26G spec Analysers still to this day prove me well. They also don't lie, no aliasing, predicable too, as non linear artifacts are known and don't fold back.  Also have exceptional  dynamic range that enables low phase noise measurements. Anpther story on the phase noise math module.

Like the old 8510 VNA, a work of art, size of a small car but to this day they struggle to beat its noise floor.  The likes of HP used to make most of their own silicon and GaaS parts to give them the edge, many were spun off commercially to help return on investment but most of the high end custom parts were consumed developing the test kit. To this day they still use devices developed decades ago as these are not viable to be respun in the latest geometries.

Sorry if there are typos.  Few beers and eyes getting older x

[shantanu@india]

To be frank I had no inkling that I would be taking up electronics as my profession when I graduated from the school of electrical engineering in 1987.While facing interview boards I felt comfortable facing questions on power system stability and machine design and had no real experience in electronics apart from assembling a transistor radio set during my schooldays.
As luck would have it my first job was in an instrumentation company which used to manufacture electrohydraulic actuators for steel plants. I was placed in the R&D team and was asked to design a opamp based system to compare the output of a Foxboro PID controller and the valve position feedback. I worked at site, sweating with my soldering iron beside the fiery hot soaking pit where steel blooms are preheated before they are rolled into billets. I still remember my adrenaline pumping when my little amateurish PCB was powered up and connected to the valve control system and the feeling of exquisite pleasure when the valve smoothly followed the position command.
From that day to the present, I'm still learning. I try to stay humble and try to pass on whatever little I know to the youngsters.