Indholdsfortegnelse for May 2023 i Practical Wireless

Icom UK is pleased to announce the availability of the IC-905 SHF/VHF/UHF/All Mode Transceiver. The company expects its first deliveries to arrive in early Summer 2023 and anticipate a price of around £3,549.95, including VAT (subject to confirmation). The optional CX-10G 10GHz transverter will follow shortly with a price of around £1,499.95 including VAT (subject to confirmation). IC-905 Main Features • 10W on 144/430/1200MHz; 2W on 2400/5600 MHz; 0.5W on 10GHz* (*Requires CX-10G transverter) • Large 4.3in touchscreen colour LCD • Real-time, high-speed spectrum scope & waterfall display • Built-in GPS • Easy digital-mode settings • High-performance GPS antenna (supplied) • Full D-STAR functions (DV/DD mode) • ATV (Amateur TV) in FM mode • SD card slot For further details about the IC-905, you can download the pre-release brochure or…

For most of us, the island of Rockall means little more than the name, alongside its neighbours Irish Sea and Shannon, that we have heard for years on the Shipping Forecast. Tiny, uninhabited and in the often-tempestuous Atlantic Ocean 250 miles from civilization, it’s not the sort of place you yearn to visit – unless your name is Nobby Styles, Fig. 1, and you hold the callsign G0VJG. Nobby is an expedition enthusiast with a long list of successful trips under his belt. Based in Dartford, Kent he is a keen long-time member of his local Cray Valley Radio Society, now in its 78th year. “It’s a very active club”, Nobby enthused. “We have all sorts of Field Days and other activities, and the Club is always keen to attract…

An easy-to-build and useful kit When you transmit, an electromagnetic wave travels to the antenna via the transmission line. If the antenna is perfectly matched, then all the energy should radiate and there will be no standing waves. If, on the other hand the antenna is not perfectly matched, there will be standing waves. In this case there could be RF in my shack due to these standing waves. It is sometimes interesting to know if you have RF in the shack while operating. If you don’t have a field strength meter, then there is no knowledge of its presence. Ofcom now recognise that Electromagnetic fields can be harmful so they have produced a spreadsheet for every amateur to work out the closest distance from a radiating antenna to be…

The new chat mode VarAC is going from strength to strength thanks to a very active development community. In fact, the calling frequencies have got so busy that we really ought to start QSYing more frequently. In the early days of the mode, where there were very few active stations, it was fine to hold short QSOs on the calling channel. This helped to make the limited activity visible to new operators. However, I’ve noticed several occasions when I’ve had to wait quite a while before I could put out a CQ call. This has been due to QSOs taking place on the calling channel. Even when that QSOs finishes, there’s often a rush of CQs, Pings, etc, so you inevitably get a few collisions that further delay the process.…

Cross Country Wireless (CCW) is a well-known name among radio enthusiasts; we have introduced several of their past and current antennas and radio/HF accessories in previous issues of RadioUser magazine and on the Radio Enthusiast website. At the time of writing, Chris Moulding at CCW is offering – through his website and eBay shop (cross_country_wireless) – this antenna, on its own (£150) or in a bundle, with the highly recommended CCW Wireless HF Coupler (£382). CCW’s product palette also includes, for instance, a Wireless Mains Filter, a Receiver Front End Protection Unit, and amplifiers for High-Z-Loop, along with Beverage-type antennas. www.crosscountrywireless.net/index.html https://tinyurl.com/yc6s2y94 https://tinyurl.com/5cuw2fru I was interested to hear about one of the company’s new offerings, the Cross Country Wireless HF Active Loop Antenna v4, and I sent out vibes and…

I-R InfraSignal Radio: for ‘Preppers ’ and Citizen-Scientists The InfraSignal Radio is a Long Wave, Extremely Low Frequency (ELF) radio receiver with built-in test and alarm functions. Its makers claim that – depending on the connected signal source sensor – it can be used for several purposes. When used with a vibration sensor, it can detect extremely weak ground vibrations from dangerous local sources such as Tornados touching the ground, Landslides, Rockslides, Mudslides, Flash floods, Tsunamis, Earthquakes and Volcanoes. When used with an electromagnetic pulse (EMP) sensor, it can detect both Solar EMP and Nuclear EMP. When used with a vibration sensor, you can monitor ground vibrations from oil well fracking, pile driving and tunnel digging. It can be used to monitor vibrations in tall buildings. When used with an…

The Buddipole Powermini 2 is described as a compact DC power management system with an inbuilt solar controller. The key features of this device (US$ 165) are as follows: • High-contrast OLED display• Power management including current and voltage readout• Powerpole input and output• Now with higher-power USB output• User-definable low-voltage alarm and cut-off• Solar controller for use with panels of up to 11 amps• Increased current handling capacity: 32 amps max www.buddipole.com/powermini.html…

Always doing something interesting, Jef Van Raepenbusch ON8NT writes, “Thierry ON2ACO made me a LORA iGate, to put on my balcony, and a Lora tracker, which produced less than 100mW [Figs 1 and 2]. I power them both from a 5V powerbank, which makes it very portable… The results are amazing: with the tracker in my car, and a mobile antenna on the roof of the car, I could follow my route even at a distance of 15km from my QTH/iGate without any problem! I am planning more tests in the future as WX is improving….” Jef notes, “LoRa is a chirp spread spectrum technology. As a result of this novel modulation having process gain LoRa can receive signals far below the noise floor. Conventional APRS is limited by having to…

Try taking an online Morse Test. Measuring your progress through your own learning is always encouraging and can also be enjoyable, leading to further progress and ability. Using this facility, you can take a simulated short test, in fact several tests, at varying speeds. This helps to give the student confidence in (1) copying ability and (2) having confidence in examination conditions. Go to this page: https://tinyurl.com/v8e8hp7b Here you can start as low as 5wpm. This is so basic as to be painful, but you can increase speed as you become more proficient and again, more confident. Your answers are given after the test with a tick if you copied correctly. As the level increases, the difficulty increases. With each higher level, the speed of the Morse code you hear…

Converted PMR radios are undoubtedly a cheap and easy way to get started on the amateur VHF bands. One very common model, the Ascom 550 (loaded with PA4DEN’s bespoke software) has become almost a standard on the 4m band. This rig is functional and robust but, because of its PMR lineage, it has one or two ‘features’ that the discerning operator might seek to avoid in a more expensive radio. One such ‘feature’ is automatic (but unannunciated) shutdown of the transmitter, typically after a few minutes on high-power transmit. This occurs when the radio senses an overheat condition, which it is prone to do more with amateur-style operation than with the PMR-style operation for which it was designed. Fans blowing on the radio’s external heatsink do help, but it’s not…

Back in the 1970s building a small project for under 20 shillings was quite a challenge as components were relatively expensive compared to today’s. Components such as FETs and bipolar transistors had only just come on the market and could be restrictive for a 14-year-old such as myself with just pocket money to spend. I always enjoyed building some of Julian Anderson’s ‘Take 20’ projects. They were ideal to learn about simple circuits as well as learning about construction methods such as tagstrips and Veroboard and making simple PCBs. Taking a leaf out of Julian’s book, here is a simple project that uses fewer than 20 components and would cost less than £20. Of course, you can just build the circuit to add to another project, or build it into a…

10M ON A CB: Tony Jones G7ETW ‘repurposes’ an old CB radio for the amateur 10m band. A SIMPLE AUDIO VSWR METER: Ken Ginn G8NDL describes an Amicus-based SWR meter with audio indication. VALVE & VINTAGE: Philip Moss M0PBM takes a look at the R209 Communications Receiver for Mobile use. GETTING STARTED ON 10M FM: With the upturn in HF conditions, James Stevens M0JCQ advocates giving FM a go on the 10m band. THE EASY WAY TO PANEL LABELLING: David Hodgkinson GI7TPO offers hints and tips on giving your project the professional look. A HOMEBREW CUBICAL QUAD ANTENNA FOR THE 4M BAND: Rod Angel G4ZUP uses garden canes, cocktail sticks and elastic bands to make a 4m beam antenna. There are all your other regular columns too, including: HF Highlights,…

The MFJ-419 is a multi-function training tool for learning to receive and send Morse Code with a straight key. It helps you learn CW and send clean CW all in one little pocket-sized box. Carry it with you to work and time at the kitchen table! Send mode operates like a Code Practice Oscillator allowing you to practice sending. The MFJ-419 will display the characters in code and English. The ‘Analyze’ setting will display your speed and timing to help you to send better. Receive mode will help you learn characters. It can send in normal spacing or two Farnsworth speed modes sending the characters faster but spacing to the programmed speed. There is a USB text mode where you can use a terminal program to send text either from…

Well made and a great performer. Definitely worth the price. Once upon a time in the UK, 4 metre Yagis were plentiful and relatively inexpensive. Back then, the frequency was only a hop, skip and a jump from the VHF TV channels. J-Beam’s founder, like so many comm’s industry bosses at that time, was a licensed amateur and produced a range of amateur antennas, excluding the 6m band for which the UK had no allocation. Regular readers will know of my nostalgia for the 4m (70MHz) band of my youth, when most equipment was either homebrew or ex-WD. There’s now more off-the-shelf equipment with 4m capability than ever there was. How ironic then, that suitable antennas are still somewhat on the ‘endangered species’ list. There’s more to life than contesting,…

Which was the first aircraft to transmit voice from air to ground and vice versa? And what equipment did they use? And when? OK, it’s not Trivial Pursuit, but these are interesting questions. Today we think nothing about aircraft use of radio, and some of us even have scanners to listen in to the fly boys and girls, out of interest. We also understand the use of HF frequencies by transocean flights, of course rapidly being replaced by the use of satellite data. However, the early days are full of interesting ideas, full of earnest development, ambition, and competition between solutions. And there are consequences today of decisions taken back then. One of them about government regulation of the airwaves. What’s to See? So, let’s start with this. Visitors could…

This receiver employs twelve transistors and four semiconductor diodes in all, but can be built in simpler form to begin, extra stages being added later. Proceeding in this way has several advantages. A useful, working receiver is obtained as soon as possible, then additional features can be provided in due course. It can also be helpful to check that portion of the receiver already wired, before fitting further stages. Excellent reception is in fact possible over all frequencies with the basic circuit having only six transistors and two diodes. Coverage is for medium waves and three short wave bands, or about 550kHz to 30MHz in all. The receiver is self-contained with battery. It is capable of long distance reception with the telescopic aerial, though range is naturally greater with a…

Welcome to the May HF Highlights. During February both the solar flux and sunspot numbers peaked above 200, leading to some excellent propagation on the higher HF bands, particularly 24 and 28MHz (the SFI was 210 and the SN 203 on 12 February). On 18 February the SFI hit an incredible 343 even though the SN was only 99. This very high solar flux measurement, however, was recorded while a solar flare was taking place and is therefore a completely inconsistent measurement. The following day the SFI was at a more normal 167. The 28MHz beacon report for February was compiled by Neil Clarke G0CAS. Excellent 28MHz conditions continued from January into February until the 26th when a geomagnetic stormed started. Paths to North America were very good with beacons…

THE VOICE OF CHATGPT: AIs can now apparently carry on a passable conversation, depending on what you classify as passable conversation. The quality of your local pub’s banter aside, an AI stuck in a text box doesn’t have much of a living, human quality. An AI that holds a conversation aloud, though, is another thing entirely. The concept is straightforward, if convoluted. A D-STAR digital voice transmission is received, which is then transcoded to regular digital audio. The audio then goes through a voice recognition engine, and that is used as a question for a ChatGPT AI. The AI’s output is then fed to a text-to-speech engine, and it speaks back with its own voice over the airwaves. The result is that radio amateurs can call into ChatGPT with questions…

Shortly after I started writing Aerials Now for RadioUser in 2018 a reader contacted me to ask if there was an easy way to compare/test a dual-band antenna he was using with his 2m/70cm handheld. It was purchased on eBay in the hope it would improve the performance of his radio over the much shorter stock antenna supplied with the set. Unfortunately, he found that results were disappointing and the stock antenna returned similar results across the bands. To improve coverage we often seek to try other antennas and quite often these will be aftermarket types so it is understandable to be disappointed if there is no improvement, as the reader had found. The antenna type in question was a ‘Nagoya NR771’, which is a 144/430MHz dual-band antenna some 396mm…