Practical Wireless的November 2025目录

SEMARC, club call GX8KVU, continues into their 4th year. They continue to be practically focussed and have a number of interest groups in the club from microwaves, microcontrollers, construction and just trying new things or things they haven’t done. They are hoping to bring together some of their past workshops and over the coming months design/adapt a design for a project that all will find useful. So they will go from schematic - LTSpice simulation - KiCad PCB design - CAD design of box and 3D printing - (hopefully) a finished and useful bit of kit. They will continue to outreach to young people and try to lower the average age! Forthcoming programme: • October 15 2025: GNU radio and Langstone type projects led by Colin G4EML (langstone Designer) •…

Omni RF are a small independent newcomer to the UK antenna market. I was intrigued to see one of their new receive aerials advertised in a recent video, in conjunction with Martin Lynch & Sons (PW September 2025, 6, 24-27, Fig. 2). I have always been really interested in what reception can be achieved with ‘loop-on-ground’, or simply ‘on-the-ground’ (LOG/OTG) antennas, including those buried underground and used for some VLF monitoring. What is more, it seems to have been a while since a new, smaller manufacturer has emerged in an area that currently seems to engage many radio hobby and amateur radio groups. The engineering and general theory of OTG antennas is covered by most of the major antenna publications (e.g. by the ARRL and RSGB) as well as in…

Spring 2023 the Belgium DX-Adventure team asked me to join them to the Andaman Islands. The Andaman and Nicobar archipelago is situated south-east of India between the Bay of Bengal and the Andaman Sea. I had never been on VU4 and many team members were friends, so my decision was quickly made. At that moment they told me that the biggest issue would be the VU3 licence, our planning was Spring 2024. We can write a complete book about getting a licence in India, so I won’t bother you with the details. It took us 18 months before all team-members got their VU3 licence. Luckily Francis ON8AZ, who was responsible for our licences, had great perseverance otherwise we would never have got our licence. Our new plan became March 2025,…

I’ve recently had a couple of mentions of a rather unique radio museum here in Somerset. It’s called, guess what, the Radio Museum. And it was founded and is run by Neil Wilson, a serious enthusiast who started collecting radio-related artefacts from the age of ten, and in 1993 opened his original Washford Radio Museum at Tropiquaria, on the site of the original BBC Washford radio station, which was in service from 1933. Its function and equipment have, of course, changed considerably in the intervening years. In March 1997, all the BBC’s domestic transmitting stations were taken over by Castle Transmission International (later to become Crown Castle UK Ltd.). In 2021 the 100kW Marconi transmitter was removed and replaced with a 12kW Nautel unit. The Marconi transmitter had been broadcasting…

10 to 12 October RSGB CONVENTION: Kents Hill Park, Milton Keynes. https://rsgb.org 12 October DARTMOOR RADIO CLUB RALLY: The Autumn Dartmoor Radio Club Rally will be held at The Yelverton War Memorial Hall, Meavy Lane, Yelverton. Devon, PL20 6AL on Sunday 12 October 2025. Free on-site Parking. There will be the usual Bring and Buy, Trader Stands and Refreshments available Doors open at 10:00hrs. Admission is £3.00. Contact Roger: Tel: 07854 088882, mailto:2e0rph@gmail.com Always check the Club website before setting out: www.dartmoorradioclub.uk 15 November THE ROCHDALE & DISTRICT AMATEUR RADIO WINTER RALLY: St. Vincent de Paul’s Hall, Norden, Rochdale, OL12 7QR. Doors open at 10am with entry still only £3. As well as our usual Traders we are pleased to announce that we have new caterers. Plenty of free parking.…

In 2001 at the bottom of the sunspot cycle Yaesu launched a portable low power, battery powered 160m-70cm multimode transceiver with integrated digital display. Many questioned the wisdom thinking that it simply wouldn’t sell. However, there was a ready market in Japan, USA, and in countries with power limited incentive licensing. For years low power QRP had been a niche activity. It was mainly the province of homebrewers doing great things with simple transmitters and efficient antennas. Suddenly Yaesu’s versatile FT-817 changed all that. QRP went mainstream proving that a big rig and a kilowatt weren’t always the way to have fun. While its battery life left something to be desired, portable activity became available to all and the ideal starter radio for many. Over the years upgrades have followed…

The improved FA-VA6 is a portable Single Port Vector Antenna Analyser designed by Michael Knitter DG5MK and is a much version of his earlier FA-VA5. Like its predecessor it has been aimed at both Amateur and Professional users. It has a frequency range of 10kHz to 1GHz with a resolution of 1Hz and while it retains basically the same signal chain as the earlier FA-VA5 it has been much improved and is designed to undertake a full range of S11 reflection measurements. Externally, it looks similar to the VA5 as it has the same anodised case and retains the BNC input socket (I am pleased to see this, I am not a fan of the SMA connectors used on a lot of analysers). This new analyser has a 320 x…

In the first issue Of PRACTICAL WIRELESS the Editor kindly invited me, along with my colleagues, to describe my favourite circuit. Since the time of publication numerous queries have been addressed to me (c/o the Editor) asking for further details and practical data in regard to the construction of a set employing the circuit I described. In each case I have been compelled by reason of our rules to ask those querists to wait for a little while, because (I did not tell them this) I was experimenting on a greatly improved version of my original idea. All readers of PRACTICAL WIRELESS are by now well aware of the fact that we absolutely refuse to supply constructional details of any set which has not been made and subjected to the…

I’d like to tell you about my current set-up for two and seventy; I won’t say why, just yet. There is a serious point to this, I promise you. It’s only a couple of pages – read on to the end, why don’t you? Power supply The PSU pictured in Fig.1, came to me in need of minor repair. The negative terminal had lost its screw-on cover, and the neon indicator in the mains switch had ‘gone’. I replaced both binding posts and the switch, at zero cost because I had the bits. The job took me all of 20 minutes; a very satisfying mend it was too. This is a bare-bones unit, with variability and no metering – hence my add-on voltmeter. The PSU is rated ‘6A constant, 8A…

FAKE PLUGS: Chris Murphy M0HLS takes readers through the pitfalls of non-compliant lugs, sockets and fuses. BOOK REVIEW: ‘CONVERSATIONS OVER THE AIRWAVES’: Richard Constantine G3UGF reviews a fascinating book about the life of Rowley Shears G8KW. BUILD A MILLIOHM METER: A constructional project from Michael Jones GW7BBY/GB2MOP. THE DELTA VEE AUTO-LOOP: A design for a Lightweight Portable Auto-Tuning HF Antenna by Frank Howell K4FMH. DIGITAL VOICE FOR HF: Eric Edwards GW8LJJ explains how to get started with digital voice for the HF bands. THE SELECTONE: Part 2 of this historic constructional project. There are all your other regular columns too, including HF Highlights, World of VHF, Data Modes, Antennas, What Next and Amateur Radio on a Budget as well as your Letters, the latest News and more. The publishers reserve…

ICOM Announces New ID-5200 and AH-6 Concept Models In addition to the launch of the IC-7300Mk2 HF/50/70MHz transceiver at the Tokyo Hamfair (reported last month), we are pleased to share even more product news from the event. Icom have used the Tokyo Hamfair to showcase a preliminary look at two new concept models: the ID-5200 144/430MHz Dual-Band Transceiver and the AH-6 Automatic Antenna Tuner. Please note that specifications may be subject to change in the future. ID-5200 144/430MHz Dual-Band Transceiver The ID-5200 is a versatile 144/430MHz dual-band transceiver which will support both FM and DV (Digital Voice) modes. A key feature is its ability to perform simultaneous dual reception of FM-FM, FM-DV and DV-DV signals. • Touchscreen Operation - The unit will feature a touchscreen for intuitive operation and easy…

Solar coronal hole high-speed streams and x-ray flares pummeled Earth during the first five months of 2025 as Solar Cycle 25 approached its peak. Electromagnetic phenomena related to the Sun’s activities also reached high levels. Observations in Alaska during this period included Ultra Low Frequency (ULF) Waves, geomagnetic storms, periodic ionosphere absorption events, solar radio emissions of many types and Sudden Frequency Deviations. A Sudden Frequency Deviation, the subject of this article, is a terrestrial radio propagation phenomenon caused by an extra-terrestrial event, a solar flare. Four strong solar x-ray flares occurred on 25 May (Table 1). However, only two occurred when the propagation paths from the remote transmitters to the receivers in the Anchorage Radio Observatory in Anchorage, Alaska were sunlit and subject to flare effects, Fig. 1. The…

Regular readers may recall that last month, I mentioned plans by the Bolton Wireless Society to fly an Arduino powered 2m beacon on a high-altitude balloon. Well, it’s happened! Steve Macdonald G4AQB takes up the story: “The Bolton Wireless Club 2m Morse Beacon launch on a High-Altitude Balloon (HAB) [Fig. 1] was a resounding success! With permission from the CAA, the final decision to launch was made for the morning of Tuesday 2 September. Other days were not possible because of weather conditions and an unstable jet stream that would carry the Balloon beyond a practical recovery. On the day before, Nick McCloud (our HAB expert) carried out final predictions and a checklist of the launch procedure and items required. Meanwhile, the 2m Morse beacon was tested for the final time ready…

After the ‘summer doldrums’ the sun suddenly sprang back into life in late August. The solar flux rose to 204 units by 27 August, with the sunspot number at 185. This was apparently as a result of two large sunspot groups growing simultaneously and it provided some excellent high-band propagation for several days. By the 29th the SFI had climbed further to 235, with long-path openings to Japan and South-East Asia as high as the 28MHz band. However, and almost inevitably, the high levels of solar activity led to a coronal mass ejection, followed by visible auroras reported as far south as Norfolk and Kent. Most solar cycles tend to have two distinct peaks and it seems very likely that the first peak has already occurred. Only time will tell…

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