Tabla de contenidos para November 2023 en Practical Wireless

SUMMER SOTA FEVER: I think it’s fair to say that I along with many others in the world of amateur radio really enjoy leaving the confines of our home shack to get out and operate portable. It adds a new dimension to our hobby and often gives us the tangible benefit of a very low noise floor in comparison to the increasingly polluted home environment. There are several schemes that encourage us to do just this, including POTA, HEMA etc. This article focuses on one of the more popular schemes, which is of course SOTA or Summits on the Air and the second annual GW SOTA party and Hog Roast held in Mid-Wales, which took place on Saturday 8 July. There are a number of SOTA events that take place…

2023 saw 51 entrants submit logs in the 40th Practical Wireless 144MHz QRP contest held on Sunday 11 June. The entrants made a total of 1951 valid contacts with stations in 33 different squares (Fig. 2). In every respect (entrants, contacts, squares worked) the numbers were up on 2022. 2023 winners The overall winner, leading single operator and leading Welsh station is the Hereford VHF Contest Group GW1YBB/P operated by Steven Clements G1YBB from Pen-Y-Gadair (800m asl), the second highest peak in the Black Mountains in South Wales IO81KW (Fig. 3). He used a Yaesu FT-817 transceiver and a 9-element DK7ZB antenna. Runner up and the leading English station is the Warrington Contest Group M0ICK/P operated by Michael Heywood operating from IO93AD. The leading fixed station is Steve Macdonald G4AQB…

Dave Thorpe G4FKI says ‘can you give a mention of the BeaconSpot website, Fig. 1?’ Of course! The site, run by the UK Microwave Group can be found at: www.beaconspot.uk/index2.php It covers beacons from 6m to 76GHz. In the introduction, it says “Beaconspot.uk presents an accurate picture of microwave and VHF/UHF beacons in Europe, plus 6m beacons worldwide. Data may be retrieved for a particular beacon, for analysis. Maps show beacon distribution by band, and spots coverage of every beacon. DXCluster incoming real time spots are collected, and outgoing spots can be sent to the DXCluster. Beacon keepers are able to maintain data on their beacon(s), and keepers can opt for email alerts whenever their beacon is spotted. ODX is recorded for every beacon, and distance to every beacon…

In the August edition of PW I reported that the latest version of the AN-SOF calculation engine, 8.20, had successfully completed validation for accuracy in accordance with the IEC FDIS 62232 standard. I added that while it was not something I had investigated I thought that AN-SOF should be accurate enough to model Electro Magnetic Field (EMF) compliance for antennas or antenna configurations. I stated that where possible, the RSGB calculator should be used but if an antenna was not in the calculator, then an AN-SOF model could likely be accurate enough to give some idea if it will be compliant or not, especially in cases of HF antennas which have ground radials or are close the ground as this is something NEC-2 can struggle with. (But not NEC-4/5) I…

Back in the early 1970s receivers for VHF were difficult to make, valves were still being used and sometimes the only way of listening on bands such as 2m and 4m involved modifying PMR equipment. In 1969 a simple VHF receiver was published in PW called the ‘CQ2’. This was a Super Regenerative receiver that used a JFET, which at the time was very new. Some readers will remember building one of these receivers as their first ever receiver for listening to stations on 2m and PMR stations. I built one on a piece of plywood and heard my very first AM station on 2m! As a way of bringing back these memories and encouraging readers to have a go at constructing a project, I have written this as a…

The Sommerkamp FT-480R and FT-780R are matching microprocessor-controlled FM/CW/SSB VHF and UHF transceivers that were manufactured by Yaesu Musen in the early 1980s. Their rugged construction, compact size, wide temperature operating range and 13.8V power make them very suitable for mobile use, and when they are operated in combination they make an effective home station for full duplex satellite working, Fig. 1. Many of these sets were imported to Europe by Wolfgang Sommerkamp and branded with his own name. In the UK, Sommerkamp equipment was sold and serviced by several competing dealers, such as the charismatic ‘Bandit’ Bill Lowe G3UBO in Matlock. UK prices in 1981 were around £380 for the FT-480R and £450 for the FT-780R, plus £63 for the optional FP-80A mains supply, Fig. 2, that could power…

Many years ago, when I was still at school, I purchased a number of military surplus radios and bundles of valves. I soon realised that I needed a means of checking which of the valves were working satisfactorily. Obtaining a professional valve tester was totally beyond the reach of my finances and even today second-hand valve testers command high prices. Encouraged by an article in (probably) Practical Wireless, I built a valve tester for my own use and, now 60 years on, it still provides a very useful functional service in my shack, Photo 1. This article will describe ways of checking Thermionic Valves to establish if they are performing within normal limits or if they are faulty. It will discuss ways of detecting and testing for various potential faults…

No apologies for yet another delve into history. After all, we are still very interested in ancient Egypt, though there is no information written by anyone living there, then. Here are some aspects that put things into perspective for newcomers to our wonderful hobby, by some one who was there, then. For amateur radio, the 1950s were nearer to the start of all radio activity, commercial or amateur, than we now are in the 2020s, Fig. 1. To get on to the 144MHz band during the 1950s was quite difficult, as it was a big jump from 28MHz to 144MHz – I don’t think there were any intermediate bands then [the UK lost the 5m band in 1947 and gained the 4m band in 1956 – ed.]. There were no…

August was a rather strange and unexpected month as regards the 28MHz propagation beacons, reported Neil Clarke G0CAS. In general, the number of beacons heard via Sporadic E was well down compared to August last year but the number of DX beacons heard via the F-layer was up, obviously because of the continued rise in the sunspot cycle. This bodes well for the coming DX season this winter. The daily average number of beacons heard via Sporadic E was nine, compared to 14 last August. The daily average of DX beacons heard was seven compared to only two last August. The first USA beacon heard (excluding 4U1UN 28200) was on the 14th when AA1SU 28234 from Vermont was logged. On the 30th beacons from W call areas 2, 3 and…

I do not want to be considered an alarmist. So, I am going to temper this piece with a note of laidbackness (sorry Don, terrible word, but it fits!). Last month I outlined the technical details of my start on the off-grid station – a fullon portable amateur radio station, powered only by rechargeable batteries, and these recharged by renewable resources. This month, I would like to get to the heart of the main rationale for this discussion – the Prepper argument. The project progress report, and more detailed amateur radio technical discussion, is at the end. I assume you know the Prepper argument. Just in case you don’t, I will summarise it like this. Civilisation as we know it is about to experience a catastrophic breakdown. Well perhaps, and…

Modern connectivity and radio technology make the prospect of operating remotely a real possibility for radio amateurs. Being able to access a home station when travelling, accessing a friend’s station, or building a station at a quiet rural location – there are lots of permutations but there are similar, underlying technical challenges needing consideration. Following a house move two years ago, I decided the best way to have a reasonable HF DX and contesting station was to build a remote station away from home. After lots of hard work, I now have a station consisting of two radios, an amplifier, tower, various antennas and rotator, all operated by controls and switches over the internet and 4G (at the remote site), which essentially means I can operate from anywhere in the…

Keys and Keyers Dear Don, I have an RSGB Centenary iambic Morse key. It worked well when I had an FT-3000 but I got tired of all the menus and things I did not use or need so I went back to my FT-101Z and my TS-530SP as well as the FT-107M (cream facia) and FT7B. Bit of a retro rebel. I used a straight key but not the RSGB key. I was not able to use my RSGB key as those rigs did not have a keyer chip. I discovered the MFJ 407E keyer. You plug in your iambic keyer to it, take a lead to the rig and away you go. There are internal jumpers inside the box to swap for solid-state rigs (FT-107M and FT7B). For valve…

Practical Wireless Rating A big step forward, excellent. Yaesu’s much anticipated dual-band System Fusion, C4FM and FM transceiver arrived with me recently. As someone who still owns earlier models, I’ve been eager to find out just what more enhancements and benefits can be packed into a mobile radio …apart from SSB and CW, that is. If you’ve read previous reviews, you’ll be aware that Yaesu has been developing not only the technical capabilities of their radios but also in a big way the customer/user interface. The early FTM-100D was conventional in appearance with C4FM capability. Radically different, the two-part FTM-400D was designed for remote mounting only, either in a vehicle or on a desk with limited space. The large touchscreen being easy to see and use. On the downside, despite…

One of the great benefits of modern rigs and ancillary equipment is that many include remote control facilities. This has enabled many stations to relocate far from the ever-increasing urban noise problems. In addition to remote operation, these controls can be helpful within the shack to aid day-to-day operations. For example, if you have multiple antennas available, having a small App on your desktop could be beneficial to control the switching. The problem with this line of development is the requirement for programming skills combined with the ability to design a suitable Graphic User Interface (GUI). Most programming languages have a steep enough learning curve to deter many from this approach. There is one exception, and that’s Node-RED. I’ve been covering this for the RSGB through a Tonight@8 presentation and…

In the first part of this article the design methods of the multiple feedback bandpass filters (MFBF) were described. Worked out examples proved that both calculation methods I presented yield the same result. Here, in this part the measurements necessary to evaluate the filter’s performance are explained and demonstrated using two actual filter modules. Building the filter, measuring the performance Component selection (capacitors, resistors) The quality (or sharpness of the passband), the bandwidth of the filter(s) is greatly affected by the selection of the components used. The main requirement here is the close tolerance: 1-2% spread of their values from the designed one of both the capacitors and the resistors alike. The MFBF needs two identical capacitors (C1 = C2), preferably of polyester type. On the circuit diagram (see Part…

The weather here in the UK may not have improved much over the years, but the same thing cannot be said of the presentation of television weather forecasts, with their sophisticated real-time graphics and computer predictions. But his month we wind the clock back a few decades to meet a long-time radio amateur who was a familiar face on BBC Television weather forecasts in the 1980s when, as we shall see, the graphics were decidedly more basic. Jim Bacon G3YLA, Fig. 1, hails from the small fenland village of Feltwell, west Norfolk. He attended Thetford Grammar School and recalls working on local farms during his school holidays, which was the traditional source of pocket money for youngsters in that rural part of the country. From school, he joined the Met…

ATU-100 AUTO TUNER ON A BUDGET: Richard Constantine G3UGF looks at the ATU-100 plus the new and latest version, the AT-100M. VINTAGE TELEVISION & RADIO: Keith Hamer and Garry Smith continue the special series looking back at the BBC’s coverage of Coronations since 1937 along with many other topics. TURN THE KNOB: Billy McFarland GM6DX creates a remote tuning knob for SDR radios. VALVE & VINTAGE: In Part 1 of a two-part feature, Tony Smith G4FAI describes the early days of Morse sending. LAB TUTORIAL: Jeff is back, this time teaching Natalie about capacitors. There are all your other regular columns too, including HF Highlights, World of VHF, Antennas, Book Reviews, What Next, The Morse Mode, Airband News, Amateur Radio on a Budget and Data Modes as well as your…