Tabla de contenidos para July 2025 en Practical Wireless

I wrote the last column the day after the April ‘145 Alive’ event, Figs 1 and 2. Regular readers will be aware that ‘145 Alive’ is a 2m FM activity period, usually three hours in duration. Various nets are co-ordinated around the country with the idea that participants can call into the nets that they can hear, contacting the net controller and any other stations that they may be able to hear on the net. Participants don’t have to stay on the same net, they can call into other nets that they can hear. The format has become popular and the events successful. The event was originally envisaged by Tim Hughes G5TM. One of the current organisers, Mark Savage M0XIC, has recently joined the board of the RSGB and is…

There are lots of interesting amateur radio Arduino projects around, some more complex than others. I came across this little gem and adapted it to use with an Arduino Nano Microcontroller. It is great for practising your Morse code. It generates random Morse code characters and displays them on an LCD display. The Morse is sounded out with a piezo speaker or external Morse oscillator. The Morse speed can be adjusted and switched between Alphabet Letters, Numbers and Other Characters. The project is easy to build without having to get involved with the programming. An ideal Take 20 project with less than 20 components and costs less than £20. Circuit The circuit, Fig. 1, uses an Arduino Nano V3 ATmega328P Microcontroller and 1602 LCD with I2C interface. This uses just…

It is in the nature of this series that it has mainly featured radio amateurs with familiar callsigns - often thanks to their successful DX activities – but whose faces might perhaps be less familiar. But thanks to the wonderful world of television the subjects of this month’s double-bill are just the opposite. One is David Palmer G7URP, host of the RSGB’s popular Tonight@8 series of webinars and for the past three years host of the online stream from the annual RSGB Convention; and the other is his wife Tammy M0TC, equally well known on the other side of the camera as mastermind of a whole range of activities, including sound, vision mixing and general continuity that are so vital in getting a broadcast smoothly to air. For readers of…

My Yaesu FT-817 quotes, in its specs, 0.2µV for 12dB SINAD on 2m. For a long time, all I knew of SINAD was that it’s an indication of receiver sensitivity and that the lower the first figure, the better was the receiver. I did of course notice that some radios were noisier than others, but reception has so many factors that SINAD long languished at the bottom of my ‘to look into list’. But I have now learned, spurred on by getting a SINAD meter, and I’d like to explore this with you. SINAD applies to all manner of receivers, but for this article I will stick to amateur radio FM receivers. What is SINAD? SINAD is an acronym, comprising the initials of Signal In Noise And Distortion. It is…

LAB TUTORIAL: Jeff and Natalie are back with a look at reactance. PASSIVE WSPR RADAR? Part 2: Nils Schiffhauer DK8OK completes his look at the likelihood of WSPR data being able to locate aircraft. HEDY LAMARR: Tony Jones G7ETW relates the story of Hedy Lamarr, inventor of frequency hopping. MY WAY TO PANEL LETTERING: Alpar Cseley HA8KT reviews and recommends ways to make your homebrew gear look professional. VINTAGE TV & RADIO: Join Keith and Garry for yet another foray into the history of broadcasting. ANTENNA RESURRECTION: Tom Tierney G0JSV tackles the challenge of replacing aged antennas. There are all your other regular columns too, including HF Highlights, World of VHF, Data Modes, Antennas, What Next, The Morse Mode and Amateur Radio on a Budget as well as your Letters,…

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In the November 2023 edition of PW, I waxed lyrical about Yaesu’s new, 55W VHF/50W UHF FTM-500DE. At last a team had sat down and re-evaluated what operators actually wanted and needed from a dual-band radio, especially when on the move or portable I think almost any experienced amateur will tell you that modern traffic, driving standards and road conditions have become much more challenging from a radio perspective in recent years. Perhaps this is why we hear more radios now operating from fixed locations to activate repeaters than actually mobile. There are lots of folk out there but they are just listening for someone else to use the repeater. Perhaps a contributing factor has been the ever-increasing range of feature-rich radios that are how shall I say, less than…

I suspect some of you may already be using the excellent WSJT-X add-on, GridTracker 2, but if not, it’s well worth a look as it could transform your Data Modes operation. While WSJT-X and JTDX are the dominant applications for Data Modes, there is plenty of scope for improvement, especially when processing the vast amount of information presented to the operator. For example, those new to FT8 can be quickly overwhelmed by the screenfuls of callsigns that appear every few seconds at the end of each decoding cycle. This is where GridTracker comes into its own and provides sophisticated filtering to make sense of the data. Originally designed to help those chasing Maidenhead grid-based awards, the software has been under constant development and now offers a vast range of filtering…

Up to now I have described using the VNA in a standalone fashion. Here the setup of the Nano, such as the Frequency Span (or Stimulus), Display Traces, Measurement Format (VSWR, LogMag, Phase etc), Traces including Trace scale and Reference levels, Measurement Channel either Port 1 S11 Reflection or Port 2 S21 Through and of course the all-important User Calibration are carried out on the device itself. This results in a handy, fully standalone, portable instrument which is capable of being taken to any location to undertake many different kinds of RF measurement tasks. One drawback of most NanoVNA’s, but not all as there are variants to the family, is the small size of the unit. This means the display may be more difficult to read for those with less…

Since Dr. Robert Westphal DJ4FF presented his idea of using WSPR log data to locate aircraft in 2020[1], it has undergone many metamorphoses and five years later seems to have found its valid version with the paper “A Proposed Global Passive Radar” [2] (“WSPR Paper” in the following) by Richard Godfrey, Dr. Hannes Cotzee ZS6BZP and Prof. Simon Maskell. The driving force behind this is the search for the crash site of the MH370 flight in March 2014, which has brought this amateur radio topic worldwide attention in many mass media outlets, including the BBC [3]. They report the concept uncritically without any professional examination. The announced publication of the WSPR paper in a peer-reviewed scientific journal - aimed at Nature, among others - has so far failed to materialize.…

Send your letters to: Practical Wireless Letters, Warners Group Publications plc West Street, Bourne, Lincs PE10 9PH E-mail: practicalwireless@warnersgroup.co.uk Super heavy space-age radios, and simple transceivers Dear Don, I often find myself empathising with those who, like Alan G3XOI (May 2025), lust after a cheap and cheerful non-sophisticated ‘simple transceiver’. In that vein, I have friends who shun the ‘Smartphone’. They much prefer to use one of those stripped-down, low-cost type mobile phones that only allows the user to receive and send telephone calls - can only receive or send a text message and cannot download those annoying apps. Maybe G3XOI has one of those? If so, I salute him for ignoring the temptation - I didn’t. Of course, the refrain about ‘simple transceivers’ has been ongoing ever since the…

HALIFAX & DISTRICT ARS NEWS: HADARS is delighted to announce the launch of its brand-new club website and digital media platform. The new site offers a wealth of free-to-view resources, including video recordings of club talks, technical articles, the club newsletter, and much more. The highlight of the new platform is a fully online Foundation License training course, created in-house by Max Townend G4SDX, James Currie Cathey G5JCC and Matt Hardy M7EUP. This innovative course features video tutorials combined with section-by-section online tests, providing a modern, flexible approach to learning. The course is available to non-members too. To register, go to: www.hadars.org.uk Click Academy (top right) to reveal the ‘Enrol now’ button. For those interested in joining HADARS, we offer a warm welcome at our club rooms in Sowerby Bridge for…

BBC coronations: Part XXVII As the Coronation approached on 2 June 1953, television engineers were concerned that many viewers’ receivers would probably not display the historic event with adequate picture and sound quality if sets were not operating at their full potential. In 1953, there were approximately 350,000 home-made television receivers in the UK. In an effort to improve the overall performance of receivers, the BBC had been approached on numerous occasions by engineers to increase the transmission time allocated to radiating Test Card ‘C’, Fig. 2. Consequently, with the forthcoming Coronation, BBC Trade Test Transmissions were extended for one hour from 16 March until 10 June. The extra hour, from 12 noon until 1pm, consisted of Test Card ‘C’ with the 440Hz tone. The BBC acknowledged the importance of…

For many HF operators ‘chasing’ stations, whether Special Event Stations, IOTA island groups or Parks on the Air, is what keeps their interest in HF piqued. But there is nothing quite like a very rarely-activated DXCC entity suddenly appearing to stir up excitement on the bands, particularly if there has been little or no prior knowledge of such an operation. And that is exactly what happened at the end of April, when Yuris Petersons YL2GM (Fig. 1) announced that, after years of attempts and many round trips from Latvia to Cape Town, he had finally been granted permission to operate from the Prince Edward and Marion Islands. These South African administered islands at about 47° South (nearly halfway between South Africa and Antarctica) are uninhabited other than by around 50…

The International Amateur Radio Union (IARU) is a renowned worldwide federation of national amateur radio organisations. The current membership of the IARU consists of more than 160 member societies in as many countries and separate territories (Table 1). The IARU plays a vital role in negotiations that relate to the fundamental aspects of amateur radio listening, such as frequency allocation, utilisation, band plans, spectrum pollution, and its future operation. The policy and management of the IARU are under the jurisdiction of its Administrative Council, which consists of three IARU officers; President, Vice-President, and Secretary and two representatives from each of the three regional organisations. The Administrative Council usually meets in conjunction with a regional conference. Each region nominates a candidate for the positions of President and Vice-President and their term…

ACFR dipole, Fig. 1, can be likened to a cross between a short loaded dipole and a multiband trapped dipole, but with only one coil or trap, and that being at one end of the dipole. The CFR dipole is constructed by feeding a quarter wavelength of wire from the centre core of a length of coax cable and allowing the common mode current generated to follow back along the outer surface of the braid. A choke coil is then located one quarter wave along the coax cable from the feedpoint to form the other half of the dipole. This prevents the common mode current continuing along the coax cable. You will note the ‘¼ wave’. Here lies the problem with adding a coil to the quarter wavelength of coax.…

All information published here reflects the situation up to and including 19th May 2024. Readers are advised to always check with the organisers of any rally or event before setting out for a visit. To get your event on this list, email the full details, as early as possible, to: practicalwireless@warnersgroup.co.uk 14 June ROCHDALE & DISTRICT AMATEUR RADIO SUMMER RALLY: St. Vincent de Paul’s Hall, Norden, Rochdale, OL12 7QR. Doors open at 10am with entry still only £3. Usual Traders and caterers. Plenty of free parking. Contact Martin Shore (Treasurer and Rally Organiser) on 07587 709006, Email: rally.radars@hotmail.com 15 June EAST SUFFOLK WIRELESS REVIVAL (IPSWICH RADIO RALLY): Kirton Recreation Ground, Back Road, Kirton IP10 0PW (just off the A14). Doors open at 9.30am and the entry fee for visitors is…