Tabla de contenidos para November 2024 en Practical Wireless

While my trusty Weller TCP (Temperature Controlled Pencil), Fig. 2, soldering station continues to work well, after 40 years it is getting a bit long in the tooth. Replacement tips are not very expensive, about £5, but they do not last very long. If I am having a prolonged construction session, the iron is on continuously all day and quite possibly all night too if I forget to turn it off. Herein lies the problem: the iron is running at the set tip temperature continuously and while not actually soldering the tip coating oxidises exposing the base metal and then the tip will not tin properly, consequently it will not transfer heat efficiently to the workpiece. When the heating elements occasionally fail they are quite expensive and are tricky to…

One of the original amateur radio applications for the Raspberry Pi configured the PWM (pulse width modulation) output to produce a WSPR RF signal directly from a pin on the Pi. Although generated at the final RF frequency, the output was a square wave, so some filtering was essential before reaching the antenna. This was a simple task achieved using a basic low-pass filter. The original project underwent a few improvements as various amateurs contributed to the open-source software. However, interest in the original project has declined, and it’s been seven years since the last update. As a result, that original software won’t run with the later Pi models and Linux editions. This has frustrated some readers who tried using the WSPR example in my Raspberry Pi Explained book. Fortunately,…

Having recently moved from Bonaire to Exmouth in Devon, I was invited to give a presentation at the Torbay Amateur Radio Society’s annual rally, which took place on 25 August. I put together a PowerPoint presentation with photos illustrating amateur radio in Bonaire (PJ4), which was appreciated by a small (but select!) audience of Devon’s HF operators, Fig. 1. Having lived overseas for nearly 20 years, this was the first UK amateur radio event I had been to for two decades and it was good to catch up with several old friends and make some new ones. A few days later Eva and I spent a week in Kraków, Poland, a grand city with plenty to see and do. We made an excursion to Auschwitz, a sobering experience indeed, where…

I have had my Heath SB200 a very long time. I got it through a friend in work who had bought it and did not really have need of a linear amplifier. Many years ago I went to a local rally and spotted a SB200 for sale, I wanted the amplifier but I had a fit of the shall I or shall I nots all day and did not buy it in the end. I have always wondered if my SB200 is the one that was left for sale that day when I decided to keep my wallet in my jacket. My main amplifier is an Ameritron when QRO is needed, so the SB200 does not get used much but it’s still handy to have as spare amplifier. Despite being…

in the UK’s best & only independent amateur radio magazine… MALAHIT DSP 2 REVIEWED: Daimon Tilley G4USI checks out this interesting SDR-based receiver. THE EIFFEL TOWER IN THE EARLY HISTORY OF RADIO: Georg Wiessala looks at how the Eiffel Tower has been used for various radio purposes over the years. PORTABLE 80m AM CLASS E TRANSMITTER: Eric Edwards GW8LJJ returns with a design for something a little different. PW 144MHz QRP CONTEST RESULTS: Colin Redwood G6MXL has the results of this year’s event. ARGONAUT RESTORATION: Mike Dunstan G8GYW tackles the restoration of a classic Ten-Tec Argonaut 509. There are all your other regular columns too, including HF Highlights, World of VHF, Data Modes, Antennas, Book Reviews, What Next, The Morse Mode and Amateur Radio on a Budget as well as…

RSGB ANNOUNCES SPECIAL ISS CONTACT: The RSGB said: “We are delighted to announce that the Radio Society of Great Britain and ARISS, in conjunction with Girlguiding Surrey West and Brooklands Museum including the Innovation Academy, have been collaborating on a special event due to take place on Saturday 5 October. Girlguiding President, HRH The Duchess of Edinburgh, will attend a planned contact with the International Space Station (ISS) as part of a visit to promote the engagement and involvement of girls and young women in science, technology, engineering and maths (STEM)”. BYLARA 45TH CELEBRATION: BYLARA (British Young Ladies Amateur Radio Association) attained 45 years of age on 29 April 2024. To celebrate, a buffet lunch for 40 guests was held at the NARSA Rally in the Lancastria Suite of the Norbreck…

As I was planning another trip to the Isle of Man, this time for the CQWW DX RTTY contest, I realised that we had to cut down the amount of equipment we were carrying. As we were operating beside the sea, verticals and dipoles are the usual antenna choice for our short visits. I got to thinking and decided I would build a triband, 10/15/20m vertical antenna with elevated radials. This would allow one run of coax and one pole (rather than three) and it would still offer us the ability to switch between the vertical and dipole antenna during the contest. I always like to recycle antenna projects where possible, so I dug out a dipole centre from an old antenna as seen in Fig. 1. I can never…

All antennas are a compromise. We all want an antenna that is small (relative to wavelength), efficient, and with a large bandwidth. You can have any two of these, but you can’t have all three. That’s physics. Some compromises are imposed on us, others are self-imposed. We each have a limit as to the space for our antenna farm, the finance available, planning considerations, what we’re prepared to put up, and what others at home are prepared to put up with. So rise to the challenge, and squeeze the most possible from every situation. Let me tell you of my physical constraints, to help explain my choices. I live on the 8th floor of a block of flats. There are several more floors above me. No attic, no roof access,…

This set was donated to the British Vintage Wireless & Television Museum, Dulwich. Sadly, it was not in its original condition by quite a long way, but fortunately the receiver circuits were unmolested. The case should be green, but was over-painted in grey, and not very well, at that, the lid is missing, which would have had a compartment to hold the two quite thick battery leads, terminated in battery terminals for connection to 6V. Additionally, it should have handles on the ends, and a leather carrying strap. Fig. 1 shows our set and Fig. 2 as it should be. There appears to be a specific loudspeaker for it, a round and presumably metal one. Fig. 3 shows the top of the chassis, Fig. 4 the underside, and Fig. 5…

Firstly, in a follow up message from last month about the presentation given to his radio club Paul M1CNK wrote: “We did a similar presentation a few years earlier on where we investigated the performance of an active RX loop. I did a comparison between the loop and my OCFD. Although the levels were lower, the improvement in SNR (on the loop) was very noticeable since I get a lot of VSDL in my garden (there are four phone lines crossing it). “This ended up turning into a club project to make an active loop kit - we made a run of about 20 kits and a lot of them were installed. I still use the club loop as my main RX antenna for most of the bands below 21MHz.…

Jeff was sat in the lab office with his feet up on a spare chair, reading last night’s football results in his paper with his usual large mug of tea on his desk. His solitude was broken when Natalie breezed into the office full of beans as usual. “Morning Jeff”, she shouted before sitting down at her desk. “Morning”, Jeff replied, “I suppose that I’d better ask what you did at college yesterday so that I can prepare for lunchtime”. “Archie took us through the relationship between magnetism and electricity in preparation for talking about inductors”, said Natalie, “A lot of it was about magnetism, or rather electromagnetism though”. “I see”, said Jeff. “Well, it is something that you need to have a grip on to understand things like inductance.…

The Moonraker Titan 10m Multimode is a 40W FM/SSB/CW and 12W AM Transceiver now in stock for just £149.95. • Frequency range: 28.000 to 29.700MHz • Mode: AM/FM/USB/LSB/PA • Output Power: Low 4W, Middle 8W, High 40W • Step: 5Hz, 10Hz, 100Hz, 1kHz, 10kHz, 100kHz • ASQ on/off • ECHO on/off • Output power adjustable • Hi-cut on/off • Beep on/off • Dual Watch • Noise Blanker on/off • ANL build-in • Scan • Roger Beep • LCR (Last Channel Recall) • Mic gain adjustable • TalkBack • Scan list • TOT • Digital RFG adjustable • A-RFG (Auto RFG) https://moonrakeronline.com…

Just over a decade ago, three former presenters/engineers at the commercial radio station Orchard FM got together for a reunion. They all were licensed amateurs and they decided, to their credit, that they would like to use their professional skills to promote their favourite hobby. The result: the highly regarded and professionally produced YouTube channel TX Factor, which celebrates its tenth birthday this year. One of the three founders was broadcaster Bob McCreadie G0FGX, Fig. 1, and I was delighted to have the opportunity to learn more about Bob’s radio activities, and how TX Factor has become such an enormous success since its launch in 2014. It all started with the school radio society Essex-born Bob was educated locally in Southend and was lucky in that his school had an…

The SDRplay RSPdx R2 (Fig. 1) follows hard on the heels of the earlier release of the RSP1B and has been planned, it appears, as the successor to the older – and popular – RSPdx variant. The RSPdx R2 provides up to 10MHz spectrum, anywhere from 1kHz to 2GHz, without gaps. According to the most recent SDRplay press releases and manuals, the new stand-out features and functionalities of the receiver are as follows. • Improvements to the RSPdx for MF frequencies and below• Better noise performance below 1MHz• Enhanced dynamic range below 2MHz, in both tuner and HDR modes• 3 software-selectable aerial inputs, including a BNC input for up to 200MHz• A 500kHz LPF (Low-Pass Filter) for LF/VLF reception• An HDR (High-Dynamic-Range) mode for enhanced performance below 2MHz• Notch filters…

In the last column, I included a brief piece about Bill Ward GM0ICF who had worked Ingolf SM6DHZ on 70cm during the Perseids meteor shower in August. Meteor scatter contacts on 70cm are very rare indeed and, as I said in the last column, I suspect that one or two that have been claimed in the past have actually been completed by aircraft scatter (which, of course, does not devalue them in terms of being an interesting and exceptional contact). Bill very kindly wrote with a few more details about the contact: “The 432MHz QSO had been in the planning for a year. Ingolf SM6FHZ was concerned that the radiant wasn’t in an ideal position and had suggested some time slots. We settled on 1100 to 1300UTC. This also was…

Various Dear Don, Many thanks for PW, which I think is great as its content has something for almost everyone. I find the range of articles excellent and the recent series by Steve G0FUW made me want to have a go at constructing a QRP set. Now you’ve published the article by Richard G3UGF on building the Kanga Rooster, I don’t know which to build. The article by Tim Bolt took me back to my days repairing televisions in the early 1970’s. We had a wobbulator in the workshop and if I remember correctly, it was used for alignment purposes to ensure a sufficient bandwidth was obtained. This makes me think that the problem Tim has encountered with his receiver relates to the IF frequency. If it should be 10.7MHz,…