Tabla de contenidos para March 2023 en Practical Wireless

Practical Wireless Rating Good value as a starter rig on 12 and 10m. Daimon Tilley G4USI practicalwireless@warnersgroup.co.uk I have never operated a CB radio, but back in the early 80’s when I was first licensed, I did buy a used Cobra AM CB from the Leicester Rally to convert for 10m FM. However, it was a project that never got started, let alone finished. Now that HF conditions are once again picking up with this new cycle, I have had a number of very successful forays on 10m in all modes, including a number of FM simplex and FM North American repeater contacts. That got me thinking about what might be available today, to get on 10m on a budget, and I scrolled through this magazine’s advertisement pages to see…

Roger Dowling G3NKH practicalwireless@warnersgroup.co.uk On 2 April 1982, Argentina invaded and occupied the Falkland Islands in the South Atlantic. The British government dispatched a naval task force to engage the Argentine Navy and Air Force before making an amphibious assault on the islands. The conflict lasted 74 days and ended with an Argentine surrender on 14 June, returning the islands to British control. It affected many of those involved in many different ways, some of which were tragic. But on a happier note, as we shall see, it was also the catalyst that finally encouraged Alan Florence, Fig. 1, to take up amateur radio and in due course become G7CDK. Early interest in Sound Recording A Londoner, now living in Cambridgeshire, Alan became very interested in sound recording as a…

David Harris mydogisfinn@gmail.com Radio Listener’s Guide 2023 (RLG) is the 34th annual edition of this essential guide to broadcasting in the UK and Ireland. The book begins with a very useful summary of radio related news stories from 2022, many of which are about the trials and tribulations of the BBC as it struggles to maintain services against a background of financial cuts. There is also the welcome news that FM radio should be with us until at least 2030. MW is very definitely on the decline with BBC Radio 5 Live likely to end its MW services by 2027. There is also a question mark over the future of BBC Radio 4 transmissions on longwave 198kHz. Many European countries have already closed their MW and LW transmitters. After the…

Frank M Howell PhD K4FMH k4fmh@arrl.net As a ham building a custom house a decade ago in an HOA-managed neighbourhood (Home Owners Association, ie typically with severe antenna restrictions – ed.), I assessed my antenna options. There were no trees on a bare corner lot at the main entrance into the neighbourhood where everyone would view the house every day. I had designed a large attic space in the plans but I also had my builder add a wire around the roofline edge underneath the shingles, thinking that a horizontal loop might come of it. This paper outlines what works in my case, both in measured and in operational terms. It may be something that other HOA-bound hams can experiment with to allow a multiband HF antenna that is not visible…

Keith Rawlings G4MIU keith.g4miu@gmail.com Although I had not originally initially intended it, this month has an antenna modelling theme. I wanted to review Marcel ON5AU’s latest book Practical Antenna Models Volume 3 in this issue and then cover some more VNA topics, but with some reader feedback and a news update, antenna modelling seems to have taken over! Practical Antenna Models Volume 3 Readers may well recall that in previous issues of PW I have reported on the series of books written by Marcel ON5AU, which cover the fascinating subject of antenna modelling using the software applications EZNEC and AutoEZ. Marcel has now released Volume 3 of ‘Practical Antenna Models’, which covers the popular subject of Loop Antennas. Firstly, though, I will briefly run over Marcel’s previous antenna modelling books…

EFHW Antenna Article Dear Don, I enjoyed reading the article on the EFHW antenna in the February issue of PW. I have been using one of these at home for several years now and it has given excellent results, with 100W SSB QSOs as far afield as Costa Rica, Texas and Jakarta. The design of the 49:1 unun followed traditional practice but I‘d like to propose a couple of suggestions for improvement. While the FT240-43 toroid is a popular choice, for operation up to 100W there is a better one: the Fair-Rite 2643251002. It is often overlooked because it is marketed as a cable core, but it uses the same type 43 material and due to its form factor has a better efficiency (and hence lower loss). I measured 91%…

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Practical Wireless Rating A lot to like! SDR comes of age. Richard Constantine G3UGF practicalwireless@warnersgroup.co.uk When the FT-710Aess arrived on my desk, I was reminded of the 2010 RSGB Convention. In a packed to overflowing lecture room I learned that simple, single-band SDRs connected to resonant antennas, though a black-art, actually worked! However, wideband reception had problems. Simple designs are subject to front-end overloading and lack selectivity. Result, broadcast and other interference can corrupt amateur band reception. Back then, SDR designs were DIY projects linked to sound cards and PC Towers. It was prophesied that by now the conventional desktop radio would be a thing of the past. How wrong can you be? Paper books still massively outsell e-books. Amateurs haven’t abandoned their love of stand-alone radios, even if the…

Mike Richards G4WNC practicalwireless@warnersgroup.co.uk Computerisation in the shack brings us many benefits, including the ability to operate our stations remotely. There are many ways to achieve this but, for data modes operators, the simplest is to use a remote access software program. These programs will usually provide access to your shack’s computer screen and keyboard from anywhere with an internet connection. However, there is a problem, as most remote access software requires a payment to activate the full features. Those few that offer a free tier will occasionally withdraw access if you use the link excessively. I recently discovered a solution to this problem with the RustDesk remote access software. RustDesk is a fully open-source package written using the Rust programming language, hence the slightly odd name. The program is…

Tim Kirby GW4VXE gw4vxe@icloud.com If you are a digital voice modes enthusiast, then the chances are high that you are running an MMDVM-based hotspot and if so, then it’s very likely that you will be using the PiStar software to run it. Although the PiStar software is excellent and stable, there haven’t been so many new releases in recent months – of course, that’s probably why it is stable! However, I recently became aware of an alternative to the PiStar software. It’s a ‘fork’ of the PiStar software, developed by Chip Cuccio W0CHP. As Chip says on his website, “This is my very highly modified and customized fork of MW0MWZ’s Pi-Star software, and I call it ‘W0CHP-PiStar-Dash’. There are so many large changes, divergences and new features, it merited…

Steve Telenius-Lowe PJ4DX teleniuslowe@gmail.com As this column is being ‘put to bed’ on 11 January, the sunspot number reached the dizzying height of 206, with the solar flux at 193 sfu. This is the highest level of solar activity recorded since the previous sunspot maximum. While on the subject of propagation, here is the 28MHz beacon report for December 2022, compiled by Neil Clarke G0CAS. “Several new or re-activated beacons were heard for the first time: 9A5ADI 28223, ZL3TEN 28228 and RC3XC 28261, which is located south-west of Moscow. In Cornwall, GB3MCB 28215 came on air and can just be heard via ground wave at my location. Paths to North America were very good with 4U1UN 28200 heard every day except the 10th, 11th and 30th. Beacons in the W4…

Richard Constantine G3UGF practicalwireless@warnersgroup.co.uk In last month’s review of the JPC-12 vertical I indicated that there was more to come from this range of portable antennas from China, principally in the form of a compact dipole, the JPC-7. Both antennas are available separately. The dipole package contains four 32cm arm extenders, two for each leg of the dipole, two telescopic whips and two resonating coils for 40-20m. Each version includes some dedicated custom parts unique to each kit variant. Here in the UK they are available as two separate packages. Expecting to receive a complete antenna, what actually arrived from China was an upgrade kit for the vertical model, not currently available in the UK, and there was no tripod. Confused yet again I made some enquiries. It transpires that…

Georg Wiessala wiessala@hotmail.com It was nice to be contacted by Moonraker recently, with the news that they were, once again, selling Steepletone world band radios,. www.steepletone.co.uk/radios https://tinyurl.com/bddhjb8t Steepletone has a long and distinguished history as a manufacturer of world receivers. Our friends at Moonraker have worked with the firm since approximately the 1970s, and the brand is well-established – remember the Steepletone MBR7 from the 1980s? A Steepletone staple that one was. www.youtube.com/watch?v=S_OOPJRy2E8 The compact and robust Steepletone radios are particularly popular, so I hear, with some DXers and travellers. Previous models have been well received, not least on account of their entry-level target market and correspondingly very reasonable price. https://tinyurl.com/yr2uezdp The Steepletone MBR1051 At just under £50, the MBR1051, Fig. 1, is an attractive proposition, in particular, if you…

A new Nevada Power PS-1335 The Nevada PS-1335 is a power supply with a difference! Not only does it provide a highly-efficient mains regulated supply with overvoltage protection, over-current protection and short protection, but by adding a battery becomes an uninterruptible supply. The PS-1335 will continue to operate equipment via the battery even when the mains supply fails. By adding a suitable 13.8V (nominal 12V) lead-acid or sealed gel battery, when the mains is on, the battery is kept charged with up to 1.8A charging current, keeping the battery ready for use. When the mains fails, a fast relay switches in the battery to keep everything going. The battery is fused with a 30A fuse. The power supply has been designed to be exceptionally RF quiet, ideal for using with…

Don Field G3XTT practicalwireless@warnersgroup.co.uk One of the products that caught my eye at Newark this year was the Rubberscopic Aerial by Phil Williams G3YPQ. This is, quite simply, a telescopic antenna for handie talkies that works on 2m and 70cm and, for good value, the marine too. It’s a telescopic antenna in a rubber sleeve that, when retracted, acts as a 70cm quarter-wave and when fully extended as a quarter wave on 2m or a three-quarter wave antenna for 70cm. As such, its performance is supposed to be somewhat better than the short two-band whip that comes with the majority of sets (such as the Yaesu FT-4X that I used for testing). Telescope just the top section in, and the whip becomes resonant on the marine band. The antenna comes with…

Nils Schiffhauer DK8OK dk8ok@gmx.net Above 30MHz, scattering of radio waves by the metal hull of aircraft, but also by the electrically conducting plasma of meteorite tails, is nothing new. For a long time, these effects have been used by radio amateurs for over-the-horizon links. In the following I would like to show how the same effects can be detected also on shortwave (HF, 3 to 30MHz) with the simplest means, SDR and free software, what can be seen there and what limits physics sets to this project. Aircraft scatter is caused by radio waves from a transmitter being scattered on the metallic outer shell of aircraft. The aircraft thus becomes a secondary transmitter/antenna whose signal mixes with that of the transmitter. Both then reach the receiver. The amount of backscattered…

Stuart Vanstone M0SGV stuartvanstone@btinternet.com In the words of the late, great Ernie Wise, “I have a long felt want”. I have been interested in radio and electronics since the about the age of eight (1957) and since then I have been messing around with all sorts of projects, from crystal sets to hi-fi amps and lots in between. These projects all have one thing in common, they need somewhere to be worked on. In the past I have used the good old kitchen table, dining room table, bedroom floor, corner of the shed, a walk-in cupboard and my last shack was in the corner of a spare bedroom. What I really wanted was a space I could call my own. Outdoors or Indoors? I became aware of the existence of…

Philip Moss M0PBM practicalwireless@warnersgroup.co.uk I purchased this from an advert in RadCom (RSGB’s member’s magazine) for the out-standing sum of £20. I knew it was minus its case, but was said to work, which was true within limits. On collection I found a set in a cardboard case. Well, it’s better than nothing one may say, keeps out the dirt at least. The set was demonstrated and, yes, a sound came out. I would later have trouble at first repeating this. The set in the photos isn’t mine partly because I sold it for use as a prop on a film set, would you believe, and partly as an unmolested set is more informative. The set photographed here, Fig. 1, is the one in Comms Corner at the British Vintage…

A TRANSMISSION MONITOR FOR THE ASCOM 550: Rod Angel G4ZUP describes a transmit monitor for this popular 4m rig. VALVE & VINTAGE: Dr Bruce Taylor HB9ANY describes radio frequency measurement before the digital age. TAKE 20, A SIMPLE TWO-STAGE RF PREAMPLIFIER: Steve Macdonald G4AQB responds to our challenge for a ‘Take 20’ project. THE DRM CHALLENGE: Kevin Ryan looks at DRM from receiver mod to software app. DISCOVER THE DATA: Billy McFarland GM6DX builds a soundcard interface for data modes. BOOK REVIEWS: David Harris checks out the latest publications from Klingenfuss. There are all your other regular columns too, including HF Highlights, World of VHF, What Next, On a Budget, Antennas, The Morse Mode, Vintage TV & Radio and Data Modes as well as your Letters, the latest News and…