Blinkenlights?

The AN/FSQ7 was probably the most light-bedecked machine I?ve ever seen, though the Stretch was also impressive.

Among the early machines, the Burroughs 220 has a very impressive front panel. It was the last commercial vacuum tube computer in the US, and had

240 neon lights on its ?main? panel and another 150 on its ?maintenance? panels straddling the main panel. You may have seen it (with neons replaced with incandescents) in several movies and as Batman?s computer in the Adam West TV show. ;-)
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Michael J. Mahon
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I only know of 3 1907s. One was in Russia and was maintained by Sperry Univac, one was at Southampton uni but had been scrapped by '78 when I came onto the scene and the other was the one at Sheffield uni and that was the one I worked on. I vaguely remember a 1901 and do remember a

1902 and a 1903 that I used to also look after but they were all core store machines.

I don't recall the 01, 02 and 03 having no lights though and if someone had asked I would have said that they did have them and been wrong. I know I used the switches to load stuff but I only remember passing data through the thing on the 1907 when one of the registers was not loading the correct bits. It would explain why if they didn't have any lights :-)

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Reply to
Rodney Pont

Its been a very long time since I touched a 1903S, but IIRC there wasn't much except a rotary selector and the row of 24 switches that was normally visible on the top left of the CPU front panel. I have dim recollections of a panel above the switches that could be flipped up and that might have had a set of lamps above the switches. That would make sense: you could input an address on the switches and then turn the knob to 'display' to see that word's contents.

As I said, I only used the switches a few times: for a short while we had a uniplexor attached so we could run Minimop on a single teletype. Executive had to be patched on the switches before use if the system had been rebooted since the last time we'd used Minimop.

Shortly after that we replaced the uniplexor with a scanner and the need for patching went away, and I reverted to applying patches through the Ops console (Exec) or via a MOP terminal (G3). FWIW our 1903S was a 32K word machine and could run G3 fairly well once I'd put in the time tuning its runtime parameters. It would support up to four MOP terminals (teletype) and one 7503 RJE device off a pair of EDS 60s. This must have been one of the smallest G3 systems to be regularly used to provide a service.

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Reply to
Martin Gregorie

Its being tried again: think Musk and the Hyperloop.

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Reply to
Martin Gregorie

Theres' a partial clue in clockspeeds: Back in the day when the 8-bit chip was king you could fairly easily build hardware with an ordinary soldering iron and debug it with a logic probe and a multimeter. If yo think you must have a 'scope as well, then a dual channel 10MHz one will do the job easily.

The kit needed to assemble SMD starts to get more complex and rather harder to use and the sort of scopes and logic analysers needed to debug hardware running at a GHZ or so, i.e. a Pi Zero or equivalent, are much more complex and expensive.

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Reply to
Martin Gregorie

Without taxpayer money - and it's open season on hyperloop there are several companies involved.

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Steve O'Hara-Smith                          |   Directable Mirror Arrays 
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Reply to
Ahem A Rivet's Shot

On a sunny day (Tue, 17 Apr 2018 21:30:16 +0000 (UTC)) it happened Martin Gregorie wrote in :

Yes and no, I'v done some GHz work, just using veroboard and tons of SMDs:

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if you scroll down you see a picture of the solder side of the board, can you see the SDMs? I just use a good temperature controlled soldering iron, an some tweezers, solder the SMD on one side first, then the other. I have a dual 10 MHz (analog) scope, but for GHz RF stuff I wrote a spectrum analyzer that uses one of those DVB-S USB sticks on a raspberry (or PC):
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Also build a down-converter for even higher frequencies or frequencies out of the DVB-S stick range.

Wrote some more complicated stuff running on my laptop here for satellite TV:

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A lot of things, even in electronics, is sales hype to sell you expensive stuff. If you know what you are doing you do not need most of that. hey I can easily buy a 10 GHz Tek scope, but I do only have the small digital scope I build, have a raspi as frequency generator (square wave):

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And how about a frequency counter in a D connector housing?:

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Or a simple cheap LC meter:

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The list is endless. You can also use a heatgun to unsolder solder and complex chips... I have seen people do miracles with that, such as replace the memory in a ipad for a bigger one (youtube video exists).

To me electronics (I sometimes say eletronix) is just 'simple', been doing it since I was < 8 years old. In those days thing were bigger :-) Couple of cheap reading glasses from the drugstore help. A magnifying glass does not (no depth perception), I do have a special visor, but never use it.

As to logic analyzers, do not use one, but you can, given the I/O speed of the raspi, in my opinion make one from a raspi, for many simple things like i2c bus or SPI bus. In fact I just do that sometimes in the software to discover i2c addresses.

But then I am somebody who works in an rxvt on the Linux desktop all the time.

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I use 9 virtual desktops with rxvts in 8 of those, plus some xterms in windows, plus one file-manager, plus a webbrowser. And 'joe' as text editor (programming editor) even to write this now. And it beats most setups in speed I think. An other rxvt to compile:

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And a third one to test:
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GPS / GLONASS module is on raspi serial GPIO port.. AIS reception via a DVB-S USB stick now on indoors piece a TV lint antenna. the CPM values are the background radiation... monitored 24/7 by an other Microchip PIC project, just in case trump hits that button in anger.
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All via ssh -Y to raspi of course.

It is easy :-)

Reply to
Jan Panteltje

It seems to have gone quiet recently, but a couple of years ago I had rather a fake feeling about it. Not from Musk, but from the original Hyperloop 1 crew (BamBrogan et al), who gave an excellent impression of being much more interested in lifestyle than engineering before disappearing and/or getting the boot in mid 2016.

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Reply to
Martin Gregorie

Interesting stuff on your website.

My background is primarily non-electronic (science degree leading to programming via Mossbauer spectroscopy and a bit of X-ray diffraction. What little I know about electronics came initially from RC model flying and building an analogue hifi amp, and then from Don Lancaster's books as I got into home computing in 1977.

I missed seeing anything equivalent to the Lancaster books for Ghz kit, so thanks for the heads-up.

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Reply to
Martin Gregorie

On a sunny day (Wed, 18 Apr 2018 09:01:57 +0000 (UTC)) it happened Martin Gregorie wrote in :

There is a Usenet group sci.electronics.design, one of the regular posters there, Winfried Hill, wrote a book: 'The art of electronics'. He worked at some university or other (cannot remember which one). People seem to like it (I have never read it). He does know the basics, and in that group you can usually get an answer.

Main thing to be aware of for GHz (my take so for what it is worth) is wavelength versus length of connections. Reflections, impedances of 1/4 wavelength, 1/2 wavelength etc pieces of wire and PCB tracks. Much is integrated these days, so on chip normally for a few GHz there is no problem, but once you decide to make PCB layouts, unless you are VERY experienced, you may need special software. PCB material loss factor. I once (my first time I came across that GHz stuff) worked with a guy who did all that by hand and left me with mouth open, something totally different from what I was used to. There are a few very experienced GHz / ultra short impulse people in that Usenet group, at least there were last time a I looked, maybe half a year ago, things do change on Usenet, there is also a lot of political babble going on there. Ha, I still fly my drone every now and then... I tis getting to regulated, was just reading they now want a worldwide registration of drones.

Reply to
Jan Panteltje

Both noted for future reference.

My next project is a multi-function timer for use in electric-powered scale or competition free flight model aircraft. This doesn't fall in the GHz category since its based on a PICAXE-14M2 chip on a small PCB, which is primarily there as a place to mount connectors. Current plans are to use a Pi2 with touch screen as its control box, which is connected to the timer to adjust servo settings and delay times.

It should also get me up to speed with using kicad to design the PCB.

Excellent point.

I did a only small amount of RC, back in the days of single channel radios and bang-bang escapements before discovering the joys of competition free flight models: designing, building and competing are all equally enjoyable aspects of that game. I learnt to fly full-size gliders in 2000 and haven't looked back: there's nothing quite like the sheer rush of a winch launch followed, on a good day, by a 200-300km cross country flight.

... and there's a move toward fitting any drone weighing over 750g or so with some form of electronic conspicuity device.

This is unsurprising, since there have already been collisions with manned aircraft and penetration of airspace around airfields is far too common. IMO just how heavy the coming regulation will be depends entirely on how well the drone flying community can control their idiots, i.e. convince them that they will only fly outside controlled airspace and below 120m in class G (uncontrolled) airspace.

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Martin    | martin at 
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Reply to
Martin Gregorie

Horowitz and Hill - a classic that's been sitting on my bookshelf for decades and is still useful!

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Steve O'Hara-Smith                          |   Directable Mirror Arrays 
C:\>WIN                                     | A better way to focus the sun 
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Reply to
Ahem A Rivet's Shot

Just reading H&H from cover to cover could drastically reduce the time needed to acquire a degree in electronics!

Although that was my degree (69 - 70) I question now whether electronics is degree level material because so much of it is commonplace and being dabbled with by schoolkids with their arduinos, robotics and raspberry pies.

Certainly in my formative years you needed a scientific degree of some sort or other before being allowed to approach the front panel of, say, a PDP8 but now you can get for a few pence (almost) an

Reply to
Gareth's Downstairs Computer

How does 'Practical Electronics for Inventors' by Paul Scherz & Simon Monk compare with H&H?

I've seen reviews that give the two books equal star ratings and say there's enough content overlap that you only need one of them.

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Reply to
Martin Gregorie

I assume you mean ARMv8 instruction set, if you are talking 64 bits. The ARM8 is a core supporting ARMv4 32bit instruction set (contemporary with the original StrongARM).

---druck

Reply to
druck

Yes.

ARMv8

Reply to
Gareth's Downstairs Computer

On a sunny day (Wed, 18 Apr 2018 11:43:34 +0000 (UTC)) it happened Martin Gregorie wrote in :

PS, I know kikad, but the thing with GHz PCBs is like this:

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That is the PCB of a cheap low noise amplifier / mixer for a satellite dish.
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Receives around 10 GHz, mixes it down to about a GHz,

The greenish round things are ceramic resonators vibrating at 9.75 and 10.6 GHz. You can actually change that frequency by filing something of the ceramics, that is why I had it open (modification).

If you take the second resonator from the right and move up you see a few funny traces that do not touch each other, those are band-filters (magnetically coupled at those frequencies), The big fat tracks like a split horse shoe around the resonators are also inductors coupling with the resonators, have a little transistor for gain to make it oscillate. The resonators are in fact in the feedback path. The thinner small zig-zag tracks are also inductors, higher values to create a high impedance to decouple the transistors. The all the way left horse-shoe holds a transistor pre-amplifier, and a pin in the middle that sticks through the board and is the antenna (signal pickup) in a horn. Horse shoe forms a cavity?

Bit lower and to the right a second pre-amplifier for a different band, with also an antenna wire sticking through the board into the receive horn. both amplified input channels are fed into the top middle transistor via 2 small caps. I think those antennas should be about 1/4 wavelength at 10 GHz, say 3/4 cm. Signal is then amplified, band filtered, and mixed down with one of the 2 ceramic oscillator signals, followed by more filtering. Such a PCB is the real GHz stuff, not so easy to design without special software. Sizes of those tracks / transformers, - everything -, needs to be exact for it to be tuned correctly. The chip top right is an about 1 GHz IF amplifier, signal goes through the board to the output connector. The chip bottom left decodes 22 kHz signals present on the output line that also functions as supply line and control line, and selects which one of the amplifiers is used and which ceramic oscillator is powered depending on the requested frequency band, the chip top left is a power supply regulator.

It is art. A different world. Only 5$ on ebay, cannot make it for that, got a bunch.

As to 'books', or 'tronix: Even you did read 'Art of Electronics' from front to back, and even if you have a degree in tronix, it is not true that you are finished, can do everything, anything.

It is the same with languages, you may be able to speak it perfectly, write it without errors, that does NOT mean you can write a novel that sells. Some politicians ... OK, do not say so much. I am the same age as the US Precedent, but still learning every day.

Many many years ago I got hold of the 'RSGB amateur radio handbook', in those days mainly tubes were used, and it had some chapters on GHz stuff, specifically 'cavities'. Then somebody gave me a book on 'radar'...

I strongly recommend that apart from the other books mentioned, if you are into building RF things yourself, also get hold of that RSGB book.

Electronics is a tool, used these days almost everywhere, where each application field has its own challenges and fascinating solutions. Over the years I have designed for - and worked at equipment used in high power stations, film, broadcasting, army, navy, missiles, medical, aerospace, security, so many things. It is a learning experience every time, every new field. The fun is to take things you learn I one application field and use that in the others. It is not true you know everything after doing your exams, that is where it starts, Couple of years ago I decided, as I was doing a lot of (am now retired, what's it? RED (movie)) RF stuff at home, it was only fair if I got my ham radio license, just to be legal and not get arrested ;-) Was sort of fun, stated 'would be a bit a a bummer if I failed'.. Was there first and left first while everybody was still sweating on the questions, got the full license. Was just memories of the past for me.

Hey ;-)

Reply to
Jan Panteltje

I remember just enough physics to appreciate what you're saying about shapes and component placement at cm and mm wavelengths, but fortunately for me the timer project PCB will not be handling any frequencies above

4800 baud comms and the standard 50 Hz PWM signal needed to drive an ESC (controller for brushless motors) and model-grade RC servos. All the higher frequencies are generated by a ceramic resonator within the PICAXE DIP package and are not available outside it.

Yes, very different!

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Reply to
Martin Gregorie

I wouldn't trust star ratings for anything like this, but there's a PDF copy of Scherz & Monk 3rd Ed around so I had a brief look.

I think the main difference is S&M is an _encyclopaedia_ and H&H is a _cookbook_. S&M has lots of pages on 'what things are', while H&H is full of examples of 'here's how to solve problem X'.

Of course, to do that H&H is also pretty encyclopaedic, but you can then follow through into the applications. It's also feasible to dip into like that: you don't need to fully understand the chapter on the behaviour of eggs before finding a recipe for souffle.

Suffice it to say, since I bought a copy of H&H 2nd edition there's only been one practical electronics book to top it - and that's H&H 3rd edition.

Theo

Reply to
Theo

On a sunny day (Thu, 19 Apr 2018 11:30:24 +0000 (UTC)) it happened Martin Gregorie wrote in :

I think the PIC internal oscillator is just an RC oscillator. Its frequency is temperature dependent, but compensated in some ways. Same for the internal RC watchdog timer, but that one is not compensated, here I use it as temperature sensor:

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just a proof of concept, from Microchip application note AN720:
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Not very accurate, a LM35 or LM335 is better.

As to driving RC servos:

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that drives 3 servos for camera movement x, y , and focus. Also used here in combination with the 'predict' program that sends orbital information to the servos about the position of amateur satellites and the ISS:
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also just a proof of concept playing around there...

I heard of PIC AXE, no idea what exactly it is, never used it. As to PCBs, for one off projects I never use PCBs, always veroboard, ready same day, and lasts for decennia. And easy to modify.

Yea, 4800 Bd is cool, my GPS modules also use it for output.

OTOH there is a tendency to ever more RF, the new Pies have WiFi. Now 2.4 GHz for control and 8 GHz for video for model aircraft / drones, etc etc.

People are working on THz (Tera Hertz) links too these days. There is no escape :-)

Reply to
Jan Panteltje

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