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Coming up in Silicon Chip A Complete DCC System for Model Trains Advertising Index This Arduino-based system uses one or two simple shields which have everything you need to run a small or medium-sized DCC-based model railway layout. It’s expandable and operates with the open-source DCC++ and JMRI software. Altronics...............................81-84 Emergency Backup Power Control Devices......................... 11 Are you prepared for an extended blackout? Most households aren’t, but there are a few relatively inexpensive options for keeping the lights (and fridge, and TV...) on, even when everyone else’s are out. Dave Thompson...................... 111 Tuneable HF Preamplifier Many low-cost SDR modules have poor HF (3-30MHz) performance. Their wideopen front ends also make them susceptible to cross-modulation from strong signal sources. This simple tuneable preamp greatly improves SDR HF performance. It has adjustable gain control and can run off a 5V supply or phantom power. Korg Nutube Preamplifier This compact and classy preamp uses an unusual device: the Kord 6P1 ‘Nutube’ twin triode, which was released in 2017! Yes, this is a new valve, and it’s unlike anything you’ve ever seen before. Note: these features are planned or are in preparation and should appear within the next few issues of Silicon Chip. The January 2020 issue is due on sale in newsagents by Monday, December 30th. Expect postal delivery of subscription copies in Australia between December 23rd and January 10th. Notes & Errata Super-9 FM Radio, November 2019: in the circuit diagram (Fig.4, pp32-33), the 4.7pF capacitor above and to the right of Q4 actually connects to Q4’s base, not its emitter. This signal is 10.7MHz above the tuned station, not fixed at 10.7MHz. Also, the 10nF capacitor shown connected between pin 13 of IC3 and ground is not present on the PCB, and not needed. Finally, the text refers to VREF from pin 10 of IC3 being applied to the anode of VC3, but it actually goes to the cathode. Shunt regulator for wind turbines, Circuit Notebook, November 2019: the drain and source of Q9 have been reversed. Q9 is not used for reverse polarity protection, but instead to regulate the supply voltage to IC1 and for the fan, to around 12V. Arduino-based Digital Audio Millivoltmeter, October 2019: in the circuit diagram (Fig.3) and PCB overlay (Fig.5), the 220nF capacitor between pin 3 of IC3 and pin 4 (GND) should be a 1µF 50V through-hole ceramic or MKT as in the parts list. The overlay incorrectly labels the PCB as 04106191 when it should be 04108191. The PCBs we sell have all these correctly marked on the silkscreen. Micromite Explore-28, September 2019: in Fig.4 on page 56, the pinout shown for REG1 is incorrect. Pin 1 is the input (IN) while pin 2 and the tab connect to GND. Full Wave 230V 10A Universal Motor Speed Controller, March 2018: a bug in the original software (1010218A) prevents the feedback speed control from working after the soft-start period. Revised software (1010218B) is available online. In the circuit diagram (Fig.1), the electrolytic capacitor connected to the junction of the 10kW and 1kW resistors to the left of diode D5 should be 10µF, not 100µF. Some PCBs sold may also show this capacitor as 100µF but the overlay diagram, Fig.2, shows the correct value of 10µF. VR2 is also shown as 1kW in the circuit, but should be 10kW as in the parts list and overlay. Stationmaster, March 2017: in the circuit diagram (Fig.2) on page 36, brake switch S1 should have been shown connected between potentiometer VR3 and the 10kW resistor, with the second pin of CON5 from the top connecting to the junction of VR3 and switch S1. 112 Silicon Chip Australia’s electronics magazine Ampec Technologies................. 37 Digi-Key Electronics.................... 3 Elf Electronics........................... 12 Embedded Logic Solutions....... 49 Emona..................................... IBC Hare & Forbes....................... OBC Hi-Q Components NZ.................. 4 Jaycar............................ IFC,53-60 Keith Rippon Kit Assembly...... 111 LD Electronics......................... 111 LEACH PCB Assembly............. 75 LEDsales................................. 111 Microchip Technology.................. 9 Mouser Electronics...................... 5 Oatley Electronics................... 105 Ocean Controls........................... 8 PCB Global............................... 12 RayMing PCB & Assembly........ 10 Rohde & Schwarz........................ 7 Silicon Chip Subscriptions....... 52 Silicon Chip Shop............. 23,109 Silicon Chip Wallchart.............. 36 The Loudspeaker Kit.com......... 13 Tronixlabs................................ 111 Vintage Radio Repairs............ 111 Wagner Electronics..................... 6 siliconchip.com.au