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MARKET CENTRE Cash in your surplus gear. Advertise it here in SILICON CHIP KIT ASSEMBLY & REPAIR PCB PRODUCTION VINTAGE RADIO REPAIRS: electrical mechanical fitter with 36 years ex­ perience and extensive knowledge of valve and transistor radios. Professional and reliable repairs. All workmanship guaranteed. $17 inspection fee plus charges for parts and labour as required. Labour fees $38 p/h. Pensioner discounts available on application. Contact Alan, VK2FALW on 0425 122 415 or email bigalradioshack<at>gmail. com PCB MANUFACTURE: single to multi­ layer. Bare board tested. One-offs to any quantity. 48 hour service. Artwork design. Excellent prices. Check out our specials: www.ldelectronics.com.au DAVE THOMPSON (the Serviceman from S ILICON C HIP) is available to help you with kit assembly, project troubleshooting, general electronics and custom design work. No job too small. Based in Christchurch, NZ but service available Australia/NZ wide. Email dave<at>davethompson.co.nz FOR SALE LEDs, BRAND NAME and generic LEDs. Heatsinks, fans, LED drivers, power supplies, LED ribbon, kits, components, hardware, EL wire. www.ledsales.com.au KEITH RIPPON KIT ASSEMBLY & REPAIR: * Australia & New Zealand; * Small production runs. Phone Keith: 0409 662 794 keith.rippon<at>gmail.com ASSORTED BOOKS FOR $5 EACH Selling assorted books on electronics and other related subjects like audio, video, programming etc. Many of them are in poor condition. Some of the books may have already been sold, but most are still available. Bulk discount available; post or pickup. All books can be viewed at: siliconchip.com.au/link/ aawx Email for a postage quote: Silicon Chip silicon<at>siliconchip.com.au Could antennas be the subject of a future article – either construction projects or enough background theory to enable readers to design and build their own? Maybe a long wire and discone for starters. (D. P., Gisborne, NZ) • Many thanks for your warm compliments regarding our magazine. Good to know that we’re appreciated ‘across the ditch’! As you are no doubt aware, the antennas required for SDRs are really no different from those for conventional ‘analog’ receivers which cover the same frequency range. The only real difference is that SDRs generally have modest-to-poor input preselection, so that they generally benefit from an active preselector between their input and the antenna. We have described many antenna construction projects in recent years, including the following, starting with the most recent: • November 2015: A 5-element Antenna for better DAB+ Reception (siliconchip.com.au/Article/9394) • October 2015: A 5-element Antenna for better FM Reception (siliconchip.com.au/Article/9137) • February 2005: A really cheap Yagi antenna for UHF CB (siliconchip. com.au/Article/2982) • January 2004: Antenna and RF Preamp for Weather Satellites (siliconchip.com.au/Article/3326) • February 2001: A 2m Elevated Groundplane Antenna (siliconchip. com.au/Article/4248) • June 1991: A Corner Reflector Antenna for UHF TV (siliconchip.com. au/Article/5918) • January 1990: An Active Antenna siliconchip.com.au Australia’s electronics magazine Where do you get those HARD-TO-GET PARTS? Where possible, the SILICON CHIP On-Line Shop stocks hard-to-get project parts, along with PCBs, programmed micros, panels and all the other bits and pieces to enable you to complete your SILICON CHIP project. SILICON CHIP On-Line SHOP www.siliconchip.com.au/shop for Shortwave Listening (siliconchip. com.au/Article/7317) • March 1988: Antennas for the VHF and UHF bands (siliconchip.com. au/Article/7788) • December 1987: Amateur radio in the VHF bands (siliconchip.com. au/Article/7855) You will find some useful information on building your own discone antenna at http://siliconchip.com.au/ link/ab25 But because discone antennas are not all that easy to build, you might consider buying a ready-made antenna or kit. One good option is from Tecsun Radios Australia: siliconchip.com.au/ link/ab39 It comes in easy-to-assemble form, is made from stainless steel, covers the frequency range from 25MHz to 1300MHz and costs $160. SC July 2020  111