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Current Radio Rules Mean Sinclair ZX Spectrum Wouldn't Fly Today 64

First time accepted submitter wisewellies writes "Ben clearly has way too much spare time on his hands, but he decided to see just how well an antiquated ZX Spectrum would hold up to modern EMC requirements. His blog is a good read if you're looking for something to do while pretending to work! From the blog: 'This year is the 30th anniversary of one of my favourite inventions of all time, the Sinclair ZX Spectrum. A few weeks ago, I finally bought one: a non-working one on eBay that I nursed back to health. Fortunately there was very little wrong with it. Unfortunately it's a 16K model, and a fairly early one at that, which won't run much software in its native state. This probably accounts for its unusually pristine condition. We took half an hour in the chamber to perform an approximate series of EN55022 measurements, to check its radiated emissions against today's standard. The question is, what have we learned as an industry since 1982?'"
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Current Radio Rules Mean Sinclair ZX Spectrum Wouldn't Fly Today

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  • Hey Hey 16K (Score:2, Funny)

    by Anonymous Coward

    Sorry, I couldn't help myself .....

    Hey Hey 16k []

  • by lobiusmoop ( 305328 ) on Thursday December 13, 2012 @11:59AM (#42274045) Homepage

    upgrade the motherboard. []

    • by Anonymous Coward

      What a retarded article. So, some one wastes their time removing the innards off a dead ZX spectrum, cram it with modern day hardware running an emulator, and now somehow that's supposed to be a ZX spectrum.

      Retards. This isn't even theseus' ship.

    • Later gen 16k models could have the memory upgraded by using the ram chips off a PC XT motherboard. I did this to one of the 16k speccys in my collection, while leaving another in original condition. Of course, these days it's probably harder to find an XT motherboard than a 48k speccy ...
  • Abject Failure? (Score:5, Insightful)

    by mschiller ( 764721 ) on Thursday December 13, 2012 @12:09PM (#42274203)

    "It’s not just a failure; it’s an abject one" Really? Now I admit the situation could be a ALOT worse with the accessories and cables, and until you've ran the test you don't know. But it's only about 6dB above the line, I've seen a lot worse problems [try 20dB!]. There is a good chance this would be a relatively easy fix when you start looking at the problem.

    A ferrite bead on the power supply cable would probably fix the "bad power" supply if indeed that's what it is. And some judicious copper taping would likely fix the other problems. Worse case you do a board spin and add ferrite beads to the I/O and possibly move suspect traces into internal layers. Worse WORSE case you change the clocking to use spread spectrum which would likely not require any changes except in the clocking circuits. None of those would prevent a "modern" version of the product from going to market.. And a good engineer could probably implement them in less than 6 weeks in a production environment...

    Plus it doesn't even manner, if you were going to bring a sinclair back to market it would draw about 20mA, run on USB power and be completely implemented on a single chip.... Because it has roughly the same processing power as a PIC uC.

    • Internal layers? What, do you think they used a 4-layer board on a $59 computer in 1980?
      • 4Layer? It was probably 2. But a worse case scenario would've been to make it more. Remember we're talking today.. Today an 8-layer board is nearly as cheap as a 2-layer board and if it meant having a legal product it would've been done.

  • by Thud457 ( 234763 ) on Thursday December 13, 2012 @12:09PM (#42274205) Homepage Journal
    The ZX didn't fly back in the day either. /rimshot
  • Yes.. but what about the zx81/TS1000?
  • by Siddly ( 675342 ) on Thursday December 13, 2012 @12:30PM (#42274565) Journal
    I have a ZX Spectrum in the loft I often see when I go up there. As far as RFI is concerned our regulations back then were non-existent. I once saw a BBC Micro for the German market, it was encased in metal and built like a tank. The ones on the UK market were plastic and caused havoc with my Amateur Radio gear until I quietened it a fair bit by coating the inside of the case with graphite spray and grounding it. TV's were another problem as they were susceptible to interference from Amateur radio transmissions operating within the legal limits and specifications and we had inspectors who audited our stations for compliance. It was all down to the manufacturers saving may be a penny or 2 by using a cheaper front-end transistor for TV's sold into the UK.
    • by chthon ( 580889 )

      Yeah, where are the days if a motorcycle passed ones house, that the TV reception was jammed?

      • by Hatta ( 162192 )

        That's today. I live within walking distance of downtown in the largest city of my state. It's very frequent that a vehicle will pass by and cause my DTV to drop out for a couple seconds. That's with a UHF antenna and amplifier. Not every vehicle, not every day, but it's often enough that I watch low def analog cable in preference to OTA free HD TV when a program is available on both.

        • by Gr8Apes ( 679165 )
          You need a better antenna, probably a much better antenna, and locate it higher. If you cannot do that, suboptimal antenna placement alone can cause all sorts of issues. I have an almost 2m rig in the attic, at a height of over 10m, and I'm on a hill. I get signal strengths no lower than 90% from about 25 channels, even 3 from a city 75 km away at a 40 degree angle from my primaries. Oh, and there's an entire suite of skyscrapers in between me and my primaries, which are roughly 40 km away. I tried the ampl
    • The TVs were made that way on purpose, to allow the TV police to easily sniff the sets' internal oscillators to track them down for taxes, right? (I'm American.)
  • by mt1955 ( 698912 ) <> on Thursday December 13, 2012 @12:47PM (#42274883) Homepage Journal

    I wrote my first real program on a Sinclair. It was for TV troubleshooting and it took you down to the section. Storage was a cassette tape and the output was composite video for black & white TV.

    Then I bought the memory expansion, took it to work and made a program for it to do cost estimate calculations. It was the 2nd computer anywhere in the company. I got promoted from cost estimating to Systems Administrator all in one go. I stayed with that company almost 30 years, then I left to start my own software company.

    A few years ago I was telling that story to a client. He pulled a mint condition Sinclair -- still in the original box -- out of his desk and gave it to me. He said it bought it to learn computers and never used it. It was like giving me the keys to my first car.

    • by Anonymous Coward

      Likewise. I was in business school 30 years ago, and a professor gave us an exercise to optimize return on a marketing budget, subject to a set of equations and constraints. "Go to the computer center on campus - it's in the DECsystem 10 there. Log in and see what values of the variables - print versus radio versus TV versus billboard - gets you the best sales revenue." Trial and error to see where to spend my marketing budget? When I have a Timex Sinclair 1000 at home, including the memory expansion o

  • by safetyinnumbers ( 1770570 ) on Thursday December 13, 2012 @12:48PM (#42274885)

    Unfortunately it's a 16K model, and a fairly early one at that, which won't run much software

    Hey! I was still supporting the 16k version with a game released in NINETY-two.

  • The Spectrum made audible noises when running. Not via the speaker AFAICT, actual noise made by the chips themselves. I've never head that with other devices.

    • Until I read this I'd completely forgotten about that little squeal that was always in the background when the Speccy was on - I suspect it was the quartz oscillator.
  • Nowadays, there are emulators and roms for just about every piece of older hardware, including the "Speccy". Here's a quickie google search link: []
    • Nowadays, there are emulators and roms for just about every piece of older hardware, including the "Speccy".

      There must be plenty of dead Speccys around, and a Raspberry Pi would fit inside the box nicely. Hooking up the Speccy keyboard to the Pi's I/O pins and knocking up a driver can't be rocket science, then you could...

      ...install a BBC Micro emulator on it and have a decent computer (ducks and runs for cover...!)

      Aaah, we had proper platform loyalty wars back in the good old days - so much better than all this cissy modern Fanbois vs. Fandroids rubbish. Tim Cook and Eric Schmitt might talk up a storm but you

  • by idontgno ( 624372 ) on Thursday December 13, 2012 @01:08PM (#42275277) Journal

    The original TRS-80 was a wideband RF jammer. Cheap PCB design, plastic (unshielded) case, lots of ribbon cable external interconnects operating at megahertz frequencies.

    One of the better ways to see whether the machine was frozen or just processing a long-running (but productive) internal loop was turn on an AM radio in the same room. Within about 3 feet, the RF noise would override all but the strongest stations and allow you to monitor the CPU's execution by the hums and burbles of the RF noise.

    It's why the original TRS-80 became the Model I, rapidly superseded by the all-in-one Model III (with lots of internal shielding). []

    • The original TRS-80 was a wideband RF jammer

      It sure was - I remember our Model I used to sit in a room upstairs in our house, directly under our TV antenna. You could tell whether my brother was playing Sea Dragon or Scarfman based on the interference on the TV.

    • by Animats ( 122034 )

      The original TRS-80 was a wideband RF jammer. Cheap PCB design, plastic (unshielded) case, lots of ribbon cable external interconnects operating at megahertz frequencies.

      Not only was the TRS-80 an RF noise generator, it was sensitive to other RF sources in the vicinity. It was noted at the time that a TRS-80 and a Milton Bradley Big Trak [] would both crash if operated near each other.

    • by Megane ( 129182 )

      I remember I had to turn mine off if the family wanted to watch TV channel 12. We lived far enough out in a rural area that we had to use a nice big antenna. which only made things worse.

      The cassette port was often used for sound output from games, but the very act of doing the timing for sound made it not much worse to just put an AM radio next to it. You kids and your Bluetooth headsets, we had REAL wireless audio back in the day!

  • would interfere with sound from the radio station, I discovered as a kid. And just when I had thought the Spectrum couldn't be any cooler...!

  • Actual Link (Score:5, Informative)

    by Thinine ( 869482 ) on Thursday December 13, 2012 @01:25PM (#42275589)
    Here's the actual blog instead of some stupid Register article: []
  • >The question is, what have we learned as an industry since 1982?

    Quite a bit.
    I have three books on electromagnetic compatibility. The most recent, Electromagnetic Compatibility Engineering (2009), is comprehensive and thick enough to stun an ox.

  • by Lord Lode ( 1290856 ) on Thursday December 13, 2012 @02:51PM (#42277197)

    I once made a QBasic program named "NOISE.BAS" on a 386 computer.

    When ran, it made the radio which was playing, produce noise for 7 seconds.

    All the program contained was:

    SLEEP 7

  • My ZX Spectrum(s) (I had a few) used to buzz when they got hot and they had a fairly big large power brick which got hot too. Anyway, there is no reason a modern reproduction should suffer from the same issues - assuming Z80 processors were still in production they're likely conformant with modern standards, or produce an ASIC (like the C64 all-in-one a few years back), and if not I'm sure an ARM soc could emulate the ZX Spectrum with no trouble at all. Throw the board into a ZX Spectrum case complete with
  • by Animats ( 122034 ) on Thursday December 13, 2012 @03:21PM (#42277717) Homepage

    We're really lucky that the FCC clamped down on RF emissions from electronics. Otherwise, we'd all be looking at big electromagnetic compatibility charts before buying anything, trying to find combinations known to work well together. Offices would need RF spectrum analyzers to figure out who brought in something that was messing up other gear. I mentioned in another post that you couldn't operate a Milton Bradley Big Trak and an TRS-80 near each other. The other side of stopping RF emissions is that the shielding makes electronics much less sensitive to RF interference.

    The development of really good RF noise management technology made modern cell phones possible. The concept of a handheld device with four radios (GSM, WiFi, GPS, and Bluetooth), all operating simultaneously within a few inches of each other, was totally beyond the RF technology of a generation ago. Two generations ago, it was so bad that marine radio stations [] had miles of separation between the receivers and the transmitters.

  • I tried a spectrum in a shop. Every time I pressed a key on the keyboard the TV monitor lost its vertical sync.

  • Last night we found out that my Mattel Electronics "Las Vegas" pinball from 1977 broadcasts its sounds across 96.1Mhz to 107.9Mhz! We started hearing the game on the boom box 30 feet across the room!
  • I've always wondered how mobile phones are allowed to exist when they interfere with anything that has speakers. I remember circa 1999 when I started noticing this strange d d d...d d d coming from computer speakers at work. We eventually realised it was that someone had a mobile phone in the room. Our VT terminals once completely freaked out when someone made a call and ever since I've wondered how this is allowed.

    I remember hearing that the Vic 20 was delayed because it needed to have shielding added,

    • As the AC implies, that's not interference from bad or unshielded electronics in the mobile (or it shouldn't be).

      An ideal mobile transmits only what it's supposed to, on the correct RF channels to communicate, and nothing else.
      Like all devices there will be other emissions, but let's assume it's very well made and effectively perfect.

      The sound on the speakers is because the speaker circuit is effectively an RF receiver, converting those high frequencies to audio. They actually demodulate the signal - uninte

  • That if marketed properly we can bilk the public out of their money every year with shiny new objects that really are not much different than last years shiny object.

  • I used to SAVE programs over the CB airwaves for other people to LOAD, and never noticed any great problems with the Speccy interfering with my CB :)

    (I put a socket on the back of my CB fist-mic - this was at the height of the CB craze after UK legalisation in Nov 1981 - so that I could plug in other mics, or line-level audio via a resistive dropper. I found that hooking it up to the Speccy I could SAVE over the air with a nice clear modulation (CB is FM in the UK - 27MHz) with enough quality that other peo

e-credibility: the non-guaranteeable likelihood that the electronic data you're seeing is genuine rather than somebody's made-up crap. - Karl Lehenbauer