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| PE VOL 25 NO 1 JANUARY 1989 COMPETITION WIN A COLOUR LCD TV 61 CONSTRUCTIONAL PROJECTS THE HOLMES MACHINE by Owen Bishop 12 Sherlock's deceptive ploy foreshadowed this blindingly simple security-enhancing mobile which in elementary steps shows Watson the table turns against the villains. CHRISTMAS FLASHERS by Chris Bowes 25 Spruce up the festive fir with flashing twinkles on its Bowes, tweek Rudolph's nose, chase the angels halo round the flickering candle, or put led-berry sauce on your random pudding. DUAL BEAM OSCILLOSCOPE - PART THREE by John Becker .... 48 The Vs and wherefores of double tracking, and how Lissajous frequently finds twisted ratios make sure you clock on time. SPECIAL FEATURES ELECTRONIC RAILWAYS - PART ONE by Neil Harding 19 Countless independent systems of electronic wizardry combine to assist passengers and goods along thousands of miles of worldwide rail networks. DIGITAL ELECTRONICS - PART FIVE by Owen Bishop 35 Customised interfaces keep logic families happily mixed, sensors hotly probe the lighter side of life, and driving the tri-state line leads to the traffic lights. REGULAR FEATURES EDITORIAL by John Becker - High-ho Silver! 9 LEADING EDGE by Barry Fox - Cordless phones 8 SPACEWATCH by Dr. Patrick Moore - Supernova news 46 INDUSTRY NOTEBOOK by Tom Ivall - The electronic persuader 57 READERS' LETTERS - and a few answers 45 MARKETPLACE - what's new, where and when 4 BOOKMARK - your Ed's view of some new books published 7 ARMCHAIR BOOKSHOP - have you browsed our good book list' 54 PCB SERVICE - professional PCBs for PE Projects 60 TRACK CENTRE - the PCB track layout page 42 BAZAAR- Readers' FREE advertising service 56 ADVERTISERS' INDEX 62
PE VOL 25 NO 2 FEBRUARY 1989 COMPETITION WIN AN ASTRA TV DISH! 61 CONSTRUCTIONAL PROJECTS SIDEREAL CLOCK by John Becker 12 When's high noon for Neptune? Is it seven o'clock for Sirius? Can you tick off Tau Cygni at ten? Build this astro-horologic clock and track the universal time for star-treks. DIGITAL ELECTRONICS - PART SIX by Owen Bishop 35 Climb the logical ladder and on the interfacing steps of knowledge let the Bishop convert you to a better belief in the ways of ADA. SPECIAL FEATURES HDTV - THE GREAT SYSTEMS BATTLE by Tom Ivall 19 The quality or viewing is much strained - but technical and economic disputes cloud the scene, and tv manufacturers can't get their acts in sync. ELECTRONIC RAILWAYS - PART TWO by Neil Harding 24 Automatic train controls signal greater efficiency for transitory traffic, and customised ticketing puts commuters on a faster track to contentment. ELECTRONICA 88- MUNICH by John Becker 28 Your Ed takes a flying visit to the World's largest electronic components trade fair and finds that 2k5 exhibitors display confidence in an exciting future. SEMICONDUCTORS - PART THIRTEEN by Andrew Armstrong 42 Cheap and cheerful, to precision and pricy - the range of opamps is enormous and widely differential. TIME AND FREQUENCY - PART THREE by Anthony H. Smith 49 Place a crystal under stress in a variety of configurations and it becomes an ideal source of precision oscillations. REGULAR FEATURES EDITORIAL by John Becker - Driving transmission 9 LEADING EDGE by Barry Fox - Flat aerials 8 SPACEWATCH by Dr. Patrick Moore - A Herculean problem 46 INDUSTRY NOTEBOOK by Tom Ivall - Technological hubris 57 READERS' LETTERS - and a few answers 41 POINTS ARISING 7 MARKETPLACE - what's new, where and when 4 BOOKMARK - we've added even more books! 54 PCB SERVICE - professional PCBs for PE Projects 60 TRACK CENTRE - the PCB track layout page 45 BAZAAR - Readers' FREE advertising service 56 ADVERTISERS! INDEX 62
PE VOL 25 NO 3 MARCH 1989 CONSTRUCTIONAL PROJECTS CAMERA SHUTTER TIMER by Robert Penfold 12 Take i-r steps to learn the focal plane truth about opening and closing times for the blind iris. DIGITAL ELECTRONICS - PART 64 by Owen Bishop 35 Reconvening the convention on conversion we plug in the breadboards for ADA's modular readouts. HF SCOPE STORE by Michael Sweet 49 An add-on circuit for last years logic analyser to let your BBC-B act as a storage scope. SPECIAL FEATURES SEMICONDUCTORS - PART FOURTEEN by Andrew Armstrong 19 The appliance of science to opamps can tone up the balance of audio amps. THE THOR SPOT by Wayne Green 24 Our American correspondent finds an erratic revolution has thorny ramifications for cdrom. HDTV, THE GREAT SYSTEMS BATTLE - PART TWO by Tom Ivall 27 Are pigeons orbiting aloft, and why are Ada and Mac such pals? Could it be they're widening their homing outlook? TACTILE DEAF AID by Vincent Johns 40 Hidden inside a wrist strap. miniature sensors allow the deaf to become aware of sounds. AUTOGUIDE by Michael Strassen 42 Let your vehicle's chat with the traffic lights screen you from the worst jams and take you on a guided auto tour. TIME AND FREQUENCY - PART FOUR by Anthony H. Smith 50 Cut crystals have greater stability when they are oven-ready. REGULAR FEATURES EDITORIAL by John Becker - Integrating Vacuums 9 LEADING EDGE by Barry Fox - SQL to search and serve 8 SPACEWATCH by Dr. Patrick Moore - Good news for Hubble and Hapag 46 INDUSTRY NOTEBOOK by Tom Ivall - Tinkering with technic 57 READERS! LETTERS - and a few answers 31 POINTS ARISING 47 PRODUCT FEATURES MARKETPLACE - what's new, where and when 4 ARMCHAIR BOOKMARK - lots more titles in our new book list 60 PCB SERVICE - professional PCBs for PE Projects 59 TRACK CENTRE - the PCB track layout page 38 BAZAAR - Readers' FREE advertising service 56 ADVERTISERS' INDEX 62
V0L25 N04 APRIL 1989 LCD TV COMPETITION THE WINNERS 61 No more nail-biting, NOW you can find out if you're one of three lucky readers to win an lcd colour tv! And there are some other interesting results shown too. CONSTRUCTIONAL PROJECTS I PC MULTIPORT by Philip Small 12 Amstrad and PC users awake! Open up more ports and let the world flow in and out on eightline dual analogue and digital data paths. DIGITAL ELECTRONICS - Computer logic by Owen Bishop 35 Why do D-typeflips flop? Could it be there are shifty characters latching-on who don't have the write to read the register? SPECIAL FEATURES HOME AUTOMATION by John Becker 19 No longer is domestic robotics solely the realm of the enthusiastic amateur. A multi-billion pound venture is underway, led by the world's leading manufacturers. It is not idle speculation, but a development having an impact here and now, and with more to come! SATELLITES - Spacecraft Launching by Tom Hvall 27 Astra's Sky is already on the Box, BSB is imminent. Forget the beamed down viewing options for a moment and find out more about eccentric celestial mechanics! SEMICONDUCTORS - Part 15 by Andrew Armstrong 41 To keep signals healthy you need to treat them carefully. An additive or two to their feedlines keeps sinewaves bouncing and dcs directly motivated. HI-TECH TIMING by Anthony H. Smith 48 How ephemeral is the ephemeris second? Very - nothing in nature runs to a definitive clock, though caesium atoms come close to it, if you monitor enough of them. REGULAR FEATURES EDITORIAL by John Becker - Domotic technology 9 LEADING EDGE by Barry Fox - the Giga-sat Touche 8 SPACEWATCH by Dr Patrick Moore - solar overview 46 INDUSTRY NOTEBOOK by Tom Ivall - patching the body 57 PRODUCT FEATURES MARKETPLACE - what's new, where and when 4 ARMCHAIR BOOKSHOP - more titles in our new book list 58 PCB SERVICE - professional PCBs for PE Projects 60 BAZAAR - Readers' FREE advertising service 56 ADVERTISERS INDEX - locating favourite stockists 62
V0L25 N05 MAY 1989 CONTENTS COMPETITION WIN A FORUM TELEPOINT PHONE' 64 Answer seven simple questions and you could win one of the latest hi-tech portable telephones - worth around £170 each! READER SURVEY TELL US WHAT'S WHAT' 37 Help us decide how PE should look for the 1 990s. You could win £100, and all entrants will receive valuable vouchers. CONSTRUCTIONAL PROJECTS KIRLIAN CAMERA by Don Phillips 12 Build an experimental supercharged aura detector and you could reap more than fringe benefits. DIGITAL ELECTRONICS by Owen Bishop 41 More computer logic and practical ways to apply it systematically. EASY-BUILD CIRCUIT by John Becker 51 Starting a new series of useful simple circuits you can build In your Idle moments. This month It's a single ch4 phone monitor. SPECIAL FEATURES HOME AUTOMATION - PART TWO by John Becker 19 How Smart Cards, interactive video and computer-linked phones offer the rainbow bridge to teleshopping, telebanklng and total home control. HI-TECH TIMING - PART TWO by Anthony H. Smith 32 Marking time from rubidium resonators to caes turn oscillators, and the clock at Rugby. STATE SIDE - WCES 89 by Wayne Green 48 Can it be true that apathy is setting in on the American consumer electronics scene? DIGITAL MULTIMETERS by Samuel Dick 27 What to consider when choosing digital multimeters, and discussing their advantages over analogue meters. TELEPOINTING THE WAY by Michael Strassen 56 Thefirst of the new Telepoint personal telephones has been launched. Read the review on the Forum then enter our competition to win one REGULAR FEATURES EDITORIAL by John Becker - Future indicative 9 LEADING EDGE by Barry Fox- Behavioural morality 8 SPACEWATCH by Dr Patrick Moore - Exploring Phobos 46 INDUSTRY NOTEBOOK by Tom IvaIl . Musical chairs 65 PRODUCT FEATURES READERS' LETTERS . and a few answers 54 MARKETPLACE . what's new, where and when 4 ARMCHAIR BOOKSHOP . lots more titles in our book list 66 PCB SERVICE . professional PCBs for PE Projects 68 BAZAARS Readers' FREE advertising service 69 ADVERTISERS' INDEX - locating favourite stockists 70
V0L25 N06 JUNE 1989 COMPETITION ASTRA TV AERIALS - THE WINNERS 36 Who's won flat aerials for Astra tv, and how geared up you all are! CONSTRUCTIONAL PROJECTS DELUXE METRONOME by Robert Penfold 12 Musicians not content with common time can now keep their tempos well tempered with a tempus perfectum constructum! SOLAR HEATING CONTROLLER by Andrew WiIIiams 27 Hot under the collar about your heating bills? Let the sun contribute to the family coffers and you'll really end up in hot water! DIGITAL ELECTRONICS by Owen Bishop 32 Logically progressing from the principles behind data chips, Owen puts them on the bus and examines their roles in computer systems. TRUE RMS METER by Rod Cooper 49 The problems of power measurement for unusual waveforms are thoroughly examined and a constructional solution presented. EASI-BUILD CIRCUIT by John Becker 57 Another in the new series of useful simple projects that you can build in your idle moments. It's a Wheeby-Jeeby siren circuit this month! SPECIAL FEATURES BOATING REVOLUTION by John Becker 19 Even the humblest messer-about-in-boats can join the revolution afloat now that micro electronics begin to rule the waves. SATELLITES - Signal Reception by Tom Ivall 40 Maximising satellite tv signal power and the vital requirements for satisfactory aerial alignment. REGULAR FEATURES EDITORIAL by John Becker- Micro greenery 9 LEADING EDGE by Barry Fox - Stereo confusion 8 SPACEWATCH by Dr Patrick Moore - Pulsars and lunar outbursts. 46 INDUSTRY NOTEBOOK by Tom vaIl - Mips for the minority 65 READERS' LETTERS - and a few answers 31 TRACK CENTRE - the pcb track layout page 54 MARKETPLACE - what's new, where and when 4 PRODUCT FEATURES BOOKMARK - your Ed looks at some new books 38 ARMCHAIR BOOKSHOP - a haven for practical bookworms 66 PCB SERVICE - professional PCBs for FE Projects 68 BAZAAR- Readers' FREE advertising service 69 ADVERTISERS' INDEX - locating favourite stockists 70
VOL 25 NO 7 JULY 1989 COMPETITION WIN A FABULOUS FOLIO COMPUTER! 61 The Folio - the latest computer from the Atari fold - and one of three could be yours for the winning if you enter our latest great competition. CONSTRUCTIONAL PROJECTS PROJECTOR SYNCHRONISER by Chris Bowes 12 Link your slide projector to a stereo tape recorder and let the silent marker add the professional touch to your presentations. ELECTRONIC THUMB by Owen Bishop 25 No need to get your fingers burnt in the search for component hot spots with this handy workshop aid. EASI-BUILD CIRCUIT by John Becker 29 Your Ed's own multipurpose workshop power supply is this month's extremely useful project for enterprising experimenters. DIGITAL ELECTRONICS by Owen Bishop 41 We've previously examined the chips and systems that comprise a computer's hardware - on now to writing the software that controls them. SPECIAL FEATURES ENCRYPTION by Mike Sanders 19 What enigma links Caesar, American Presidents, birthdays and barbers? The cryptic answers are revealed as we examine linguistic security. SATELLITES - Signal coding and polarising by Tom Ivall 35 There's much more to understanding Astra, BSB and other tv satellites than knowing which channel number should be set on the receiver dial. BOATING REVOLUTION - PART TWO by John Becker 49 Whatever your craft, the latest microelectronic devices can bring enhanced precision and greater safety to your seafaring. REGULAR FEATURES EDITORIAL by John Becker - Exhibiting reliability 9 LEADING EDGE by Barry Fox - Rating data links 8 SPACEWATCH by Dr Patrick Moore - Herstmonceux and Phobos 2 . . . . .46 INDUSTRY NOTEBOOK by Tom IvaIl - Imaging Creation 57 PRODUCT FEATURES MARKETPLACE - what's new, where and when 4 POINTS ARISING 17 BOOKMARK - your Ed looks at some new books 32 PCB SERVICE - professional PCBs for PE Projects 60 BAZAAR- Readers' FREE advertising service 58 ADVERTISERS' INDEX - locating favourite stockists 62
VOL 25 NO 8 AUGUST 1989 COMPETITIONS WIN THE NEW SHARP 10 ORGANISER! 61 Sharpen up your organisational intelligence with a Sharp 10 personal electronic organiser. Worth £170. Three to win just pit your wits against the Editor's authoritative punning! TELEPOINT TELEPHONES - THE WINNERS 53 Did you ring the bell in our May 89 competition? With decorum Ed's quorum drew five for the Forum - we've lined up the answers, so don't ignore 'em! CONSTRUCTIONAL PROJECTS STEPPING MOTOR DRIVER by Mark Stuart 12 Step into the world of robotics by adding motive power to your home micro using the new M5804 chip in a multimode motor module. HAND CLAPPER by Harvey Kent 26 With comparative ease you can automatically applaud us for putting rhythm in your chip board with this handy effects box. EASI-BUILD CIRCUIT by John Becker 49 Fancy exterminating the Doctor? Build a Vodalek voice box as this month's project and speakeasi like a robot. SPECIAL FEATURES HF RADIO - PART ONE by Mike Sanders 19 Wave upon wave, layer upon layer, electromagnetic radiation randomly fills the universe yet from chaos we seek order and communication, and achieve them! How? We examine the principles. BOATING REVOLUTION - CONCLUSION by John Becker 35 Monitoring your craft's precise position is greatly simplified by the new generations of satellite-linked microterminals. ENCRYPTION - PART TWO by Mike Sanders 39 How the modes and standards of data encryption enhance electronic security for personal and corporate communications and finance. REGULAR FEATURES EDITORIAL by John Becker - Home automation update 9 LEADING EDGE by Barry Fox- Mac scrambling 8 SPACEWATCH by Dr Patrick Moore The New Technology Telescope 46 INDUSTRY NOTEBOOK by Torn vaIl - CIM and Society 57 READERS' LETTERS - and a few answers 30 PRODUCT FEATURES MARKETPLACE - what's new, where and when 4 ARMCHAIR BOOKSHOP - a haven for practical bookworms 58 PCB SERVICE - professional PCBs for PE Projects 60 BAZAAR - Readers' FREE advertising service 52 ADVERTISERS' INDEX - locating favourite stockists 62
VOL25 NO9 SEPTEMBER 1989 COMPETITION WIN A MAPLIN TRIPLE-TRACE 20MHZ SCOPE! 61 Three Maplin precision laboratory oscilloscopes worth nearly £300 to be won - and one could be yours for the price of a stamp! CONSTRUCTIONAL PROJECTS FREQUENCY COUNTER AND GENERATOR by John Becker..12 Your Ed's new multipurpose workshop test aid: a 4MHz frequency counter with 8-digit lcd, plus integral audio and digital frequency generators. HOME SECURITY CONTROLLER by Kevin Browne 25 Let a hi-tech alarm system monitor your precious property. With microprocessor control, numerous complex facilities can be implemented. ELECTRONIC MOLE-DETESTER by Edwin Chicken MBE 42 It you're at war with underground mini-miners, reorientate their territorial ambitions with our bleep-squeak humane mole-deterrent. EASI-BUILD CIRCUIT by John Becker 49 In this month's project a simple audio compressor keeps your mono mods in limited peak condition. 64-LINE OUTPUT PORT by R. Milner and A. Horsman 52 Another imaginative idea in our ingenuity Unlimited series. Two innovative PE readers multiplex 64 control lines from an 8-bit source. SPECIAL FEATURES HF RADIO - PART TWO by Mike Sanders 21 In which we investigate the mysteries of oscillators, phase locked loops, phase detectors, and balanced mixers. DIGITAL ELECTRONICS by Owen Bishop 35 How great an impact does digital electronics have on our lives; what are the benefits, the problems and future prospects; and will you pass the test? ASK PE - NUMBER ONE by Andrew Armstrong 41 How can I remotely control audio levels?', asks a PE reader. Master-mind Andrew shows one way of doing it in the first of our new query-quest columns. REGULAR FEATURES EDITORIAL by John Becker - Consumer scoring 9 LEADING EDGE by Barry Fox - Blooming pianos 8 SPACEWATCH by Dr Patrick Moore - Voyager 2 and Neptune 46 INDUSTRY NOTEBOOK by Tom Ivall - Mergers and takeovers 57 PRODUCT FEATURES MARKETPLACE - what's new, where and when 4 BOOKMARK - your Ed looks at some new books 45 ARMCHAIR BOOKSHOP - haven for practical bookworms 58 PCB SERVICE - professional PCBs for PE Projects 60 BAZAAR - Readers' FREE advertising service 53 ADVERTISERS' INDEX - locating favourite stockists 62
VOL 25 NO 10 OCTOBER 1989 CONSTRUCTIONAL PROJECTS TELESCOPE CONTROL INTERFACE by David Clarke 12 Whether you want to control a telescope or any other equipment, this versatile parallelserial interface could provide the answer. MONO-STEREO ECHO STATION by John Becker 27 Herewith, by popular demand, a new multioption audio delay-line unit for echo, reverb, multitracking, chorus and other favourite functions. EASI-BUILD CIRCUIT by John Becker 32 Let your voice become a third hand with this simple sound-operated remote switching circuit. HOME SECURITY CONTROLLER - PART TWO by Kevin Browne 49 Constructive data on the microprocessor controlled alarm system that can assist you in setting up your own crime-watch scheme. SPECIAL FEATURES ELECTRONIC SNAPSHOTS by Barry Fox 17 Film is dead for home movie making; will it also die for happy holiday still-snapping, killedoff by magnetic disks? TRANSPUTER TRAINER REVIEW by Robert Penfold 23 Flight Electronics! training system enables those with programming and electronic skills to come to grips with transputer technology. ASK PE - NUMBER TWO by Andrew Armstrong 34 A reader asks about stability when taking signal feedback from a loudspeaker, and is given an answer that also includes line regulation. DIGITAL ELECTRONICS by Owen Bishop 36 Digital electronics can provide solutions in many applications, and we can provide the solutions to last month's exam - how well did you do? HF RADIO - PART THREE by Mike Sanders 41 How modulation piggy-backs audio signals onto radio frequencies, plus a look at amplifiers, distortion, heatsinks and filters. REGULAR FEATURES EDITORIAL by John Becker- Party preparations 9 LEADING EDGE by Barry Fox - Digital stereo tv 8 SPACEWATCH by Dr Patrick Moore - Brown dwarfs and jet-sets 46 INDUSTRY NOTEBOOK by Tom Ivall - End of a love affair 57 READERS' LETTERS - and a few answers 31 PRODUCT FEATURES MARKETPLACE - what's new, where and when 4 BAZAAR- Readers FREE advertising service 53 ARMCHAIR BOOKSHOP - haven for practical bookworms 58 PCB SERVICE - professional PCBs for PE Projects 45 ADVERTISERS' INDEX - locating favourite stockists 62
Volume 25 Number 11 - November 1989 COMPETITIONS! 25TH ANNIVERSARY COMPETITION 72 25 years of PE -25 fabulous prizes to be won! In our easy-to-enter competition you could win an Acorn Archimedes computer, or Cirkit digital meters, or free subscription to PE for 25 years, or ... well, have a look for yourself! COMPETITION RESULTS 39 Who the winners are in the Atari Folio Pocket PC and Sharp 10-7000 Personal Organiser competitions. Plus the rewarded readers in our Survey. PARALLELING SIR CLIVE by John Becker 9 An exclusive interview with PE's favourite inventive entrepreneur, Sir Clive Sinclair, some of his diverse history, and how he won the PE Technology Award. IN THE BEGINNING by Fred Bennett 15 Fred planned PE's creation and nourished his innovation from foundation to empire. He tells us about the exciting early days. THE MIDDLE YEARS by Mike Kenward 23 PE's editor 1977-85 recalls how he was harnessed, by Fred Bennett, but eventually took the thoroughbred reins. TIME TRAVELLING TECHNOLOGY by John Becker 25 A nostalgic trip through highlights of PE's history, stopping on route to savour the parallel tale of technology in the making. TOASTING TRANSITIONS by Richard Barron 33 Piloting PE from Poole to London, Richard steered the editorial helm during 1986, setting course with the new master. FUTURE FULFILMENT by John Becker 35 On a bleak winter's day your current Ed was made an offer he couldn't refuse, and now keeps PE on bright tracks to a golden future. FROM PE TO PROSPERITY by Anthony H. Smith 40 Building a PE metal detector set a reader in search of fortune - and he found it with the aid of friends and a Bishop's ring! 2014? WHEW! by Dr Wayne Green 42 An American perspective of technology's success and failure over the last quarter century, and how the green conscious world might be by 2014. FLEMING AND THE VALVE by John Becker 54 Your Ed finds another technology birthday to commemorate, but does it pose a problem of delayed priorities? Who will challenge his heroic heresy? CONSTRUCTIONAL PROJECTS TELESCOPE CONTROLLER - PART TWO by David Clarke 48 Concluding circuits and software for the versatile parallel-serial interface that can control a telescope or other equipment. EXTENDED TIMING by Andrew Armstrong 66 This month's Ask PE query : How can one achieve a timed period longer than conventional components allow? Here's one possible solution. SPECIAL FEATURES HF RADIO - PART FOUR by Mike Sanders 52 Moving on from filters, we peruse the characteristics of tuned and highefficiency amplifiers, and summarise past transmission. UCT MEASUREMENTS by Anthony H. Smith 55 Some pitfalls encountered with counters, and how to counter them. Tony probes the reasons for avoidable inaccuracies. MICRO GENIUS by Jenny Welsh 71 Has the Home Computer another face you may seldom see? Jenny weaves a rueful tale of warning for the uninitiated! REGULAR FEATURES EDITORIAL by John Becker - Golden futures 8 LEADING EDGE by Barry Fox - The next 25 years 15 INDUSTRY NOTEBOOK by Tom vaIl -25 years of l.T 45 SPACEWATCH by Dr Patrick Moore - Spacing the 80's 46 READERS' LETTERS - and a few answers 59 POINTS ARISING - The query clarifying corner 17 PRODUCT FEATURES NEWS AND MARKETPLACE - what's new, where and when 60 BAZAAR - Readers' FREE advertising service 64 PCB SERVICE - professional PCBs for PE Projects 67 BOOKMARK - Your Ed browses through some new books 74 ARMCHAIR BOOKSHOP - haven for practical bookworms 76 ADVERTISERS' INDEX - locating favourite stockists 78
VOL 25 NO 12 DECEMBER 1989 CONTENTS COMPETITION RESULTS MAPLINOSCOPY WINNERS' 45 All is revealed - the winners and the answers to the competition with Maplin 20MHz oscilloscope as prizes! CONSTRUCTIONAL PROJECTS VIDEO AGC STABILISER by Robert Penfold 12 Copy-protected video tapes may not satisfactorily play back on some video machines. Using an age stabilising interface might help cure the problem. MONO-STEREO ECHO STATION - PART TWO by John Becker.27 Taking up where we left off in Oct 89, we conclude the construction and setting-up of this very versatile audio effects modifier. THERMAL CONVERSION VOLTMETER by Rod Cooper 35 A companion to the true rms ammeter of June 89, this ingenious voltmeter is specifically designed for use in power electronics. GATED TIMING by Andrew Armstrong 38 As an answer to this month's Ask PE query, Andrew describes another way in which timing periods can be extended, using selectable digital gates. MINI METRONOME by John Becker 48 A flashy led and audio additive circuit doubly marks accented beats for musicians, and is this month's Easi-build project. SPECIAL FEATURES REPAIRING THE AL8O by Vivian Capel 17 The manufacturers of the old-time favourite power amp may be obsolete, but the module needn't bet HF RADIO - PART FIVE by Mike Sanders 21 In the penultimate article in the series, special refinements to receivers are examined, including age and squelch considerations. A PARTY TO REMEMBER by John Becker 30 The Party s over but the memories (and the hangovers?) linger on. Nostalgic reunions, spirited chats, a shining award, an odd-ode and a tour round the Steam Museum suitably commemorated our 25th Birthday. UCT MEASUREMENTS - PART TWO by Anthony H. Smith 41 Concluding tbs authoritative advice on how to get the best out of universal counter timer measurements. REGULAR FEATURES EDITORIAL by John Becker - Cop out 9 LEADING EDGE by Barry Fox - Deaf video phones 8 INDUSTRY NOTEBOOK by Tom Ivall - "Sorry, wrong person!" 57 SPACEWATCH by Dr Patrick Moore - Neptune and Venus 46 PRODUCT FEATURES ANNUAL INDEX - January to December 1989 ........... 60 NEWS AND MARKETPLACE - what's new, where and when 4 PCB SERVICE - professional PCBs for PE Projects 44 BOOKMARK - Your Ed browses through some new books 50 ARMCHAIR BOOKSHOP- haven for practical bookworms 58 ADVERTISERS' INDEX - locating favourite stockists 62 | ||
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