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MARKET CENTRE Cash in your surplus gear. Advertise it here in SILICON CHIP ENGINEERING SERVICES NSW/ACT - Electronics IT Specialist 25 years experience – aerospace – IPC J-STD-001ES – SMD/SMT – electronics & PCB design – embedded systems – hardware & software development – installations – repairs - contact ELCOMTEL – mob: 0468 3527 6415 – www. elcomtel.com.au – info<at>elcomtel. com.au FOR SALE LEDs! Nichia, Cree and other brand name LEDs at excellent prices. LED drivers, including ultra-reliable linear driver options. Many other interesting and hard-to-find electronic items! www.ledsales.com.au questronix.com.au – audiovisual experts solve home, corporate security and devotional installation & editing woes. QuestAV CYP, Kramer TVone (02) 4343 1970 or sales<at>questronix. com.au SOLAR PANELS LOW COST: full range 5W to 250W, eg: 40W/12V Poly $69, 130W/12V $169, 190W/24V $165, 200W/12V $225, 250W/24V $225, 230W Poly $190. AGM Batteries: 7AH $19.50, 9AH $24.50, 20AH $52.50, 55AH $129, 105AH $199, 220AH $399. (03) 94705851 or (03) 9478 0080 chris<at>lowenergydevelopments.com.au www.lowenergydevelopments.com.au 544 High St, Preston 3072, Melbourne. PCBs & Micros: Silicon Chip Pub­ lications can supply PCBs and programmed micros for all recent (and some not so recent) projects described in the magazine – see the PartShop ad- vert in this issue. Order online or phone (02) 9939 3295. PCBs MADE, ONE OR MANY. Any format, hobbyists welcome. Sesame Electronics Phone (02) 8068 2713. sesame<at>sesame.com.au www.sesame.com.au KIT ASSEMBLY & REPAIR KEITH RIPPON KIT ASSEMBLY & REPAIR: * Australia & New Zealand; * Small production runs. Phone Keith 0409 662 794. keith.rippon<at>gmail.com VINTAGE RADIO REPAIRS: electrical mechanical fitter with 36 years experience and extensive knowledge of valve and transistor radios. Professional and reliable repairs. All workmanship guaranteed. $10 inspection fee plus charges for parts and labour as required. Labour fees $35 p/h. Pensioner discounts available on application. Contact Alan on 0425 122 415 or email bigal007<at> internode.on.net WANTED CIRCUIT & DESIGN IDEAS: SILICON CHIP pays up to $60 for Circut Notebook items or you could win a $150 gift voucher from Hare & Forbes. See the Circuit Notebook pages for details. WANTED: EARLY HIFIs, AMPLIFIERS, Speakers, Turntables, Valves, Books, Quad, Leak, Pye, Lowther, Ortofon, ELNEC IC PROGRAMMERS High quality Realistic prices Free software updates Large range of adaptors Windows 95/98/Me/NT/2k/XP CLEVERSCOPE USB OSCILLOSCOPES 2 x 100MSa/s 10bit inputs + trigger 100MHz bandwidth 8 x digital inputs 4M samples/input Sig-gen + spectrum analyser Windows 98/Me/NT/2k/XP IMAGECRAFT C COMPILERS ANSI C compilers, Windows IDE AVR, TMS430, ARM7/ARM9 68HC08, 68HC11, 68HC12 GRANTRONICS PTY LTD www.grantronics.com.au SME, Western Electric, Altec, Marantz, McIntosh, Tannoy, Goodmans, Wharfedale, radio and wireless. Collector/ Hobbyist will pay cash. (07) 5471 1062. johnmurt<at>highprofile.com.au WANTED: Palec M-32 multimeter, any condition as long as meter scale is in good shape. james.goding<at>monash. edu Issues Getting Dog-Eared? REAL VALUE AT Keep your copies of SILICON CHIP safe with these handy binders $14.95 * PLUS P &P Order from www.siliconchip.com.au/Shop/4 or call (02) 9939 3295 and quote your credit card number.*See website for overseas prices. ADVERTISING IN MARKET CENTRE Classified Ad Rates: $29.50 for up to 20 words plus 85 cents for each additional word. Display ads in Market Centre start at $110.00. All prices include GST. Closing date: 5 weeks prior to month of sale. To book, email the text to silicon<at>siliconchip.com.au and include your name, address & credit card details, or phone Glyn (02) 9939 3295 or 0431 792 293. siliconchip.com.au July 2013  103 Advertising Index ADM Instrument Engineering......... 5 Altronics.................................. 80-83 Dimitech....................................... 21 Elcomtel..................................... 103 Embedded Logic Solutions.......... 99 Emona Instruments...................... 61 Front Panel Express....................... 7 Grantronics................................. 103 Hare & Forbes.......................... OBC High Profile Communications..... 103 Instant PCBs.............................. 103 Ask SILICON CHIP . . . continued from page 102 conductors. If the circuit were prone to failure, that would be a good test. For extra protection in this circuit for the Jacob’s ladder we added a 16V zener diode across the 7555’s supply. That zener was only included due to the much higher coil discharge. VHF antenna for Band 3 reception With the imminent switch-over to digital TV in our major capital cities this year, some readers may not be aware that after this the Government’s digital dividend will result in re-stacking the television channels to band 3 (VHF), at least for the major capital cities. In May 1986, Leo Simpson and Bob Flynn presented an article in the old EA magazine for a high-gain Yagi antenna for Channel 28, something that I built and had great success with in capturing transmissions from outlying country areas from Melbourne. Currently, this antenna is used to receive Melbourne digital TV as well as DAB+ radio and it still works well. I was wondering if SILICON CHIP could do a similar project especially designed to operate in band 3 for channels 6-12. From my perspective, I can’t wait to eliminate the directors no longer required to receive the old analog channels such as ABC 2; the pigeons would need to find a new home! (A. P., North Sunshine, Vic). • We covered this topic last month. The problem with describing DIY antennas is that the cost of aluminium rods etc is so expensive that by the time you buy all the material and 104  Silicon Chip DOWNLOAD OUR CATALOG at Jaycar .............................. IFC,49-56 www.iinet.net.au/~worcom Keith Rippon .............................. 103 WORLDWIDE ELECTRONIC COMPONENTS PO Box 631, Hillarys, WA 6923 Ph: (08) 9307 7305 Fax: (08) 9307 7309 Email: worcom<at>iinet.net.au LED Sales.................................. 103 KitStop.......................................... 10 Low Energy Developments........ 103 Microchip Technology................... 23 Mikroelektronika......................... IBC hardware required, it is cheaper to purchase the finished antenna. As a bonus, it will be fully anodised and should last for many years. Having said that, there is probably nothing to stop you from modifying an existing wide band Yagi by removing the long directors and reflector needed for channels below Channel 6. The folded dipole would need to be reduced in dimension as well. A photo in last month’s article showed how an existing antenna would need to be modified. However, unless the antenna was in quite good condition initially, trying to modify and refurbish it could be a lot of time and effort. CFL & LED flicker with solid-state relays I have a home with several homeautomation solid state relays (SSRs) with low-voltage DC inputs switching 230VAC and these have been operating for several years with no issues with incandescent globes. However, whenever I try to put in CFL globes, all “flash” at about two cycles per minute which is not ideal; so I am stuck with incandescents. Recently, I purchased several Osram and Philips LED globes and tested these. The Osram ones do not flash but the Philips ones do flash, so my question is, is there anything I can add (eg, a capacitor) to prevent this from happening either on the DC or Ocean Controls.............................. 9 Quest Electronics....................... 103 Quick Thinking Pty Ltd................... 7 Radio, TV & Hobbies DVD............ 93 RF Modules................................ 104 Sesame Electronics................... 103 Silicon Chip Binders.............. 95,103 Silicon Chip Online Shop........ 96-97 Silicon Chip Subscriptions........... 73 Syndetic Pty Ltd........................... 59 Tekmark Australia........................... 6 Wiltronics........................................ 8 Worldwide Elect. Components... 104 (more likely) the AC side? I prefer the Philips globes as they give a warmer output than the Osram. I also have 12V garden lights (LEDs) that operate via one of these SSRs and a transformer and they also flash but at a slower rate; every three seconds. I would rather not use relays as I don’t see the need in this day and age. I just thought you may have some suggestions how to overcome this. (D. H., via email). • It is likely that the SSRs have a minimum operating current and the CFLs and LEDs may be close to that current and thereby cause them to flash. That is why incandescents with their higher current are OK. Apart from increasing the load current, nothing can be done to cure the problem. SC siliconchip.com.au