Indholdsfortegnelse for December 2022 i Practical Wireless

practicalwireless@warnersgroup.co.uk Where have the years gone? For the past two years the RSGB Convention has happened, but online. And, I gather, very successfully too although I must admit to not having participated – for me the Convention is all about meeting friends and catching up with the gossip. In fact, other than for lockdowns, etc, I have missed only one RSGB Convention (formerly the HF Convention) in over 40 years and that was because I was on a DXpedition on Christmas Island! Anyway, last year, I am told, something like 5,000 folk watched one or more of the online lectures. As a result, this year the RSGB opted for a combined in-person/online event as they didn’t want to lose that large number of attendees, both here in the UK and,…

Q1. The first issue of Practical Wireless was published in September 1932, Fig. 1. How much did cost at the newsagent? Q2. If you applied for an amateur radio licence in England when the first issue of Practical Wireless was published, what prefix would you have been issued: (a) G2, G3 or G4, (b) G2, G5 or G6, (c) G3, G4 or G5, or (d) G5, G6 or G8? Q3. Solar cycles are approximately 11 years long, Fig. 2, but in which year did Solar Cycle number 1 begin: (a) 1555, (b) 1655, (c) 1755, or (d) 1855? Q4. Who originally developed frequency modulation (FM) transmission: (a) Heinrich Hertz, (b) Peter Eckersley, (c) Lee de Forest, or (d) Edwin Armstrong? Q5. The ARRL’s DXCC award was introduced in which year:…

practicalwireless@warnersgroup.co.uk With the worst of the Covid-19 pandemic hopefully behind us, opportunities to promote amateur radio to the public face-to-face have started to open up again. One technique in particular is to operate individually or as a club in locations that are accessible to the public. If you do this and are armed with information about what you are doing, the curious will start to engage with you. How you do this can depend on the scale of your operation and your intentions. One-Man Band If you’re operating just by yourself with the primary focus of participating in a contest or to activating a particular hilltop or area of countryside, then you may not have time to deal with questions from the public. In this case a simple notice explaining…

practicalwireless@warnersgroup.co.uk This month I’m continuing to look at modes that support keyboard QSOs as opposed to the automated exchanges of FT8, FT4, etc. Last month it was PSK31 but this time I turn my attention to a new kid on the block, VarAC. VarAC VarAC is a new mode specifically designed to support keyboard-to-keyboard, chat style QSOs. In use it reminds me of AMTOR, but it is very different to that mode as you will see. VarAC has been developed by Irad Deutsch 4Z1AC (hence the mode name) and is supported by a lively group of enthusiasts. The idea was to create a straightforward chat mode where most of the procedural exchange of callsigns, signal reports, etc. could be automated. This approach means you can concentrate your attention on the…

ericgw8ljj@outlook.com When building a low voltage shack power supply or testing a commercially built one for solid-state projects or for providing the power source for the shack transceiver, the current as well as the voltage needs to be evaluated for any set of applications. This can be a problem because a specific value load resistor is needed for each application, or one that can ‘load’ the power supply to its maximum capability. The resistance value of the external test load along with the power capability (wattage) of the load will depend on the required voltage and current measurements of the power supply. If the power supply to be measured is 13.8 volts (V) and the rated current is 30 Amps (A), a resistor of 0.46 Ohms (Ω) with a wattage…

Send your letters to: Practical Wireless Letters, Warners Group Publications plc West Street, Bourne, Lincs PE10 9PH E-mail: practicalwireless@warnersgroup.co.uk Star Letter The Star Letter will receive a voucher worth £20 to spend on items from our Book Store, or other services offered by Practical Wireless The MCR 1 Dear Don, The item by Philip Moss about the MCR 1 (November PW) made interesting reading as I also have one. Several years ago, when working in the radio and TV trade we were called out to a customer we had known for many years. He was an SWL and wrote articles on aviation, monitoring, and radio related subjects for several magazines. He never had an amateur licence but he did have modern HF radio sets. After completing the repair and drinking…

JOTA FROM ESSEX: The Essex Ham team was active over the JOTA weekend (15/16 October 2022) at the Belchamps Scout Activity Centre in Hockley, Essex. Close to 200 Cubs, Scouts and Explorers from across the region signed up to take part in this special event, allowing them to work towards their communication badges through a range of fun ‘hands-on’ activities. As well as the traditional JOTA ‘greetings messages’ (not helped by HF contesters on JOTA frequencies), the event offered the chance to send coded Morse messages, radio direction-finding, one-time pad code-breaking, recordings of Numbers Stations, PMR radio chases, demonstrations of military radio systems, as well as live video calls with other Scouting groups around the world. New to the event this year was a ‘blindfold navigation challenge’, where teams of…

6 November BUSHVALLEY ARC RALLY: Limavady Football Club. Doors open at 11 am; entry is £3 with a door prize ticket. 6 November HOLSWORTHY RADIO RALLY (HARC): Holsworthy Leisure Centre, Well Park, Western Road, Holsworthy, Devon EX22 6DH. Traders from 8:00 am; doors open to the public at 10.00am. (BB | CR | D | TS). Traders & General Enquiries, Contact the Secretary via email. m0omc@m0omc.co.uk  https://tinyurl.com/yckypn5v 19 November THE ROCHDALE & DISTRICT AMA-TEUR RADIO WINTER RALLY: The Rochdale & District Amateur Radio Winter Rally will take place in St Vincent de Paul’s Hall, Norden, Rochdale, OL12 7QR. Doors will be open at 10 am with the entry fee still only £3 (CR | FP | TS). rozallin@gmail.com dave@cardens.me.uk  01706 633 400  0781 367 1296 19 November WILTSHIRE WINTER INDOOR…

practicalwireless@warnersgroup.co.uk I like to think that it is in the nature of most amateur radio operators to tinker, and this month I am going to describe two very practical and simple projects, which take old redundant laptops and repurpose two of their components for use in amateur radio, or other purposes. First of all, as I described in my last article, old laptops can sometimes be given a new ‘set of legs’ by a fresh install of an Operating System, especially a Linux distribution, or indeed perhaps additional RAM etc. But, inevitably, there comes a point where that is not worthwhile or necessary. What happens to the laptop then? Most recycling centres will take them and dispose of them appropriately. Before you take it to a recycling centre though, why…

teleniuslowe@gmail.com Back in 2014 I ordered an Acom 1500 HF/6m linear amplifier from the American dealer and had it shipped to Bonaire. It was expensive, but it was the first piece of new equipment I had bought in almost a decade and I figured it would probably outlast me! After three years of almost daily use I was so pleased with the amplifier that I wrote a user review for PW [1]. It continued to work perfectly until 29 July this year but, when I turned the amplifier on again that same evening, the normal 180-second warm-up period would not begin and instead ‘Auto Protection: PN07’ appeared on the front panel display. There had been no prior warning of anything starting to go wrong: it had always worked perfectly – until…

g4fai@btinternet.com The B2 spy set, or Type 3 Mk.II, to use its official designation, was one of a series of SOE (Special Operations Executive) clandestine sets designed in 1942 by Captain John I. Brown G3EUR at SOE Station IX, The Frythe, near Welwyn, Hertfordshire. It was the best-known of all the sets used for clandestine operations in WW2. When used by agents and resistance groups operating in occupied territory, it was normally carried in a suitcase with all necessary accessories. When used by military personnel operating in the field with partisan groups, etc, it was packed in two watertight containers, dropped by parachute, and then carried as backpacks. Danger from Detection The function of a clandestine wireless operator was to keep in contact with a Home Station in Britain; to…

practicalwireless@warnersgroup.co.uk This month’s special Christmas project describes a three transistor radio which is highly selective together with a good output level. By careful ‘shopping around’ among the advertisers the complete radio may be built for under 20s; as usual less than twenty components are used A few months ago our project was a one transistor radio which did not require an external aerial and operated a loudspeaker; however this design did have limitations – especially volume which was mentioned in the text. With Christmas just around the corner there must be many readers who would like to take advantage of their interest in electronics and knock up something for the children, and it was with this specifically in mind that this month’s project was planned. First, the radio had to…

SolderGO launches comfortable ergonomic smart soldering iron to raise funding for the first production run exclusively on the platform kickstarter known to bring projects to life. The SolderGO iron features an easy-to-use, intuitive user interface and OLED display, compact ergonomic size with a full-size tip, which is portable and can minimise workbench footprint. The SolderGO provides 72W of power for rapid heat-up time, temperature stability and thermal recovery with a user adjustable soldering temperature range up to 450⁰C. The iron is DC powered for portability and can be connected to a mains power supply or various batteries which the iron can detect and protect. Sleep and wake-up modes are employed to increase tip life and efficiency. The screen can be flipped for left or righthanded use. There is a large…

practicalwireless@warnersgroup.co.uk When I was 15, no Morse meant no Licence as back then it was an international requirement. I don’t mind admitting that I struggled with it, failing my test a couple of times. Ironically, later the code served me well as a radio officer at sea and even later as an RSGB Morse examiner. The original receiving test was a written exam with plain language and numbers tested separately. This simply didn’t prepare you for the real world. Procedural signals such as start, stop, comma and break signs didn’t figure in the amateur radio test, neither did short cut expressions such as 73, 88, ‘es’ for and, or ‘bcnu’ (be seeing you). The original and still superior form of text messaging (I’m biased). Before computers, BC that is, when…

teleniuslowe@gmail.com Welcome to the December HF Highlights and, if it is not too early, I’d like to wish a very Merry Christmas to all readers. The Solar Flux Index (SFI) peaked at 163 on 11 October and was at or above 150 for weeks, leading to enhanced propagation on the higher HF bands and F2 openings as high as 50MHz. The Sunspot Number (SN) was briefly as high as 173 on 3 October but had fallen by the 11th of the month, see Table 1. Solar Cycle 25 is coming along very nicely: Fig. 1(a) shows how the cycle’s Sunspot Number has been progressing while Fig. 1(b) shows the 10.7cm Solar Flux over the same period, courtesy of the Space Weather Prediction Center, part of the US government’s National Oceanic…

gw4vxe@icloud.com If you were with us last month, you will have read that I had an intriguing time with an app called DVSwitch Mobile running on an Android device. It allowed me to connect to Allstar nodes around the world and make some interesting contacts. I could see there was also a capability to connect to digital radio networks such as D-STAR, DMR, Fusion as well as NXDN and P25. However, that didn’t seem to be available without setting up a DVSwitch server. With my interest piqued, I found a Raspberry Pi that was not getting too much use and set about creating a DVSwitch server. Fortunately, this proved very simple indeed, following the excellent instructions at: http://dvswitch.org/DVSwitch_install.pdf I created an image, which I transferred onto microSD card, and booted…

practicalwireless@warnersgroup.co.uk It was Wednesday lunchtime in the electronics lab and Jeff and Natalie had just finished their lunches. Natalie wandered over to Jeff’s desk ready for the usual electronics lesson that she got from Jeff on Wednesdays, typically based around what she had learned at college the previous day. “So what’s our topic this week?” Jeff asked. “Waveforms”, Natalie replied, “And things like frequency, peak, and RMS values”. “OK”, said Jeff. “Explain to me what an electronic waveform is then”. “Well”, Natalie replied, “An electronic waveform is basically a signal that can represent an electrical quantity such as voltage or current. They are two dimensional and like a graph, have a vertical and a horizontal axis from which we can derive information about the waveform. From the horizontal, or X…