Tabla de contenidos para September 2023 en Practical Wireless

practicalwireless@warnersgroup.co.uk Portable operation has never been more practical or popular. When it comes to compact, lightweight transceivers with all-mode outputs from 5 to 100 watts there’s a wealth of new and pre-owned radios to suit just about every pocket. Homebrew QRP is alive and well and many operators are out and about all year round. Lithium Iron, gel cells, deep cycle leisure batteries and solar panels have revolutionised portable operation. Staggering up hill, lugging lead acid car batteries and generators is a thing of the past – Newbies take note, you’ve never had it so good! While the equipment situation has never been better, the laws of physics don’t really change. Every radio needs an effective portable antenna. MC-750 v JPC-12 Regular readers will know that portable antennas seem to…

practicalwireless@warnersgroup.co.uk While in Italy for the recent World Radiosport Team Championship (see previous report), I signed up for a day of visiting to Villa Griffone and the Bologna Museum of Communications. Villa Griffone lies quite close to Bologna but in the countryside. It houses the official Marconi Museum. It’s quite a substantial building, as can be seen from the photographs, and was bought by the Marconi family in the mid-1800s. Guglielmo was the youngest son of the family, his father being Italian and his mother Irish from the Jameson family (as in the whisky empire). As a young lad Guglielmo became interested in things electrical and by his mid-teens was already undertaking what for the time were quite innovative experiments. His parents allowed him to use one of the attic…

keith.g4miu@gmail.com In the June edition of PW Georg Wiessala evaluated the XHDATA D-109 ‘Multi-band Radio’ and with an eye to improving reception during his review he used it with an externally connected random length of wire, which was fed to the receiver via a ‘balun’. This raised a question from reader Paul Capewell on how he could connect one of these baluns to the similar XDATA D808. The type of balun used by Georg is a receiving type, often called a Magnetic Long Wire Balun (MLB). However, it should be more correctly termed an Unun. The reason why it is not a balun is because the output to the radio is via a coaxial feeder, which is classed as unbalanced as the screen of the cable is grounded to the receiver’s…

Keith405625.kh1@gmail.com Garry405625.gs@gmail.com Televising the Coronation of King George VI and Queen Elizabeth in 1937 was an extremely important landmark in the history of the BBC Television Service. The BBC’s mobile television unit, making the first ‘true’ television outside broadcast, enabled viewers to enjoy, in the comfort of their own homes, the spectacle of the Royal procession, Fig. 1. The television pictures of the King smiling as his carriage passed by the cameras captured the imagination of the viewers and of the Press, who declared it “the supreme triumph of television to date”. Before the Coronation, a number of outside broadcasts were transmitted from the grounds of Alexandra Park, but these were limited in scope due to the comparatively short lengths of Emitron cable used to connect the site with the…

Have you got something to tell our readers about? If so, then email practicalwireless@warnersgroup.co.uk Fresh from Friedrichshafen show comes a new 1.5kW HF Linear amplifier with internal Auto Tuner, the RF Kit B26-PA. Dual LDMOS devices rated at 3400 Watts ensure a safe operating margin, even at full power. Lightweight at only 16kg, large 7in colour display and <1mS for very fast QSK CW. In stock and on show at their London showroom. £5799.00, including VAT. For more information see: HamRadio.co.uk/RFKit JNC Radio SV6301A 1Mz-6.3GHz VNA: One of the largest for screen size (7in IPS LCD capacitive) Vector Network Analyser covering 1MHz-6.3GHz. This really is a beautifully built instrument supplied in a nice carry case. A full video presentation is available on the MLandS.tv YouTube Channel. For more information see:…

michael@gb2mop.org I’m sure that at some point in our radio careers most of us will have come across an AC/DC radio, also referred to as a universal set. As the term suggests, an AC/DC radio will run happily from either an AC or a DC mains supply. History DC mains power is unheard of these days, but when electricity started to be supplied to Industry in the late 19th century and subsequently to our homes at the start of the 20th century the supply could be AC or DC and a variety of voltages from 100 to 240. The reasons for choosing AC over DC vary. The battle of the currents raged in America with Thomas Edison supporting DC distribution while Nicola Tesla and Westinghouse supported an AC system. In…

gw4vxe@icloud.com I’m sure many readers will have seen the details of OFCOM’s amateur licence consultation. From my perspective, it looked mainly positive. I know a few people have expressed concerns about gateways, repeaters and beacons being deployed all ‘over the place’ without being coordinated. Co-ordination will be the key, as well as following the bandplans. Clearly this is something that will need to be worked through in practice to avoid interference. I like the ability to create low power beacons and I can see that others will enjoy the ability to experiment more widely with repeaters and gateways. Increased power levels will be positive for those with Full licences who enjoy experimenting with scatter modes or EME – or simply winkling out weak DX. Intermediate and Foundation licensees benefit from…

teleniuslowe@gmail.com We start this month with news of the World Radiosport Team Championship (WRTC), which takes place every four years (although this year’s event, rather like the Olympic Games on which it is modelled, was postponed by a year due to the Covid pandemic). WRTC runs concurrently with the IARU HF Championship contest, which is held on the second full weekend of July each year (8/9 July in 2023). This year WRTC took place around Bologna in Italy. 58 two-person teams from all over the world travelled there to compete on what was as close as possible to a ‘level playing field’, using the same antennas and power levels. All competing stations had callsigns beginning I4, followed by a single digit and a single letter. The UK was represented by…

m1mwd@gmx.com While waiting for the new equipment to arrive, I ‘reactivated’ a dead laptop, and got to work with the software. I read almost everything I could find online about various data modes, and watched YouTube videos too. I immediately eliminated JT65, which is mostly used for Moonbounce and other exotic experiments. But it still left a long list of modes, and associated software. Of course, FT8 was easily top of that list. I never had much interest in data modes, much preferring chatting on SSB. But a recent dinner conversation added an interesting observation, which had not occurred to me before. We were discussing ‘keeping in touch’, generally, and I said I preferred people to just call on the phone. Which caused shrieks of amusement around the table. “No…

THERMIONIC VALVE TESTING: David Hodgkinson GI7TPO looks at testing of valves, useful for those taking care of and restoring old gear. CW BANDPASS FILTER DESIGN: Alpar Cseley HA8KT addresses the design of bandpass filters for CW reception. FROM ANOTHER ERA: Georg Wiessala puts together a temporary RTTY/CW receiving station with some vintage gems from the makers of the ERA Microreader and avoids computers altogether, for once. THE RCA-VICTOR AR88: Philip Moss M0PBM gets to grips with this class receiver. DAB BAND SCANNER: Kevin Ryan describes his solution for a scanner to identify band openings. There are all your other regular columns too, including HF Highlights, World of VHF, Antennas, Book Reviews, Vintage TV & Radio, What Next, The Morse Mode, Amateur Radio on a Budget and Data Modes as well…

TX Factor is back on the air with a brand new episode. Bob McCreadie G0FGX, along with friends Noel Matthews G8GTZ and Dave Crump G8GKQ, head out into the Wiltshire countryside to put the new Icom IC-905 all-mode microwave transceiver through its paces. Not content with a few Watts of microwave power, Bob treks off to the heart of England to visit the UK’s last remaining shortwave transmission station. Woofferton, near Ludlow is a former BBC station and now in private ownership, but still busy sending out daily transmissions across the world with up to 250kW of HF power. Bob has a guided tour of the antenna arrays and the gleaming transmission hall, which still contains some of the original Marconi senders installed back in the 1960s. TX Factor is…

practicalwireless@warnersgroup.co.uk I know what you’re thinking, FM is for the VHF and UHF bands right? Well usually yes, but there is an exception on the 10m band and again typically only at certain points in the sunspot cycle. The 10m band is an interesting band, exhibiting qualities of an HF and a VHF band. Sometimes you’ll only be able to work local stations, other times it will support worldwide contacts. 10m FM offers a world of fun, which you can enjoy, especially now as sunspot cycle 25 is starting to warm up. 10m is the only HF band that has a FM allocation in the band plan [1]. It certainly wouldn’t be welcomed much elsewhere, due to the comparatively large amount of bandwidth needed for a single QSO! 10m is…

practicalwireless@warnersgroup.co.uk The World Radiosport Team Championship started in 1990 in Seattle, in conjunction with the Goodwill Games organised by media mogul Ted Turner to bring together sports people from both sides of the Iron Curtain. The idea behind the first WRTC was to do the same with amateur radio, bringing together radio enthusiasts from Russia, the USA and elsewhere to meet socially and to compete on something close to a level playing field, with host stations being relatively close together in the Seattle area and therefore experiencing much the same propagation. Subsequent WRTCs have taken place every four years, hosted in Finland, Serbia, Brazil, Los Angeles, Moscow, New England and Germany. I was privileged to be a referee in Brazil and a Judge in Moscow and New England. Referee, Judge?…

practicalwireless@warnersgroup.co.uk During the past few Data Modes, I’ve looked at many of the technologies behind the SDR transceivers that have come to dominate amateur radio equipment. While the details can get complex, the overall principles are relatively straightforward, as I hope I’ve shown you. However, SDR technology is evolving rapidly, and the mobile device market is driving exciting new developments. The most likely outcome for us is more integrated devices. When you look at the SDR technology in today’s amateur kit, most high-end units employ a fast ADC (Analogue-to-Digital Converter) followed by an FPGA (Field Programmable Gate Array). The FPGA is problematic because they are expensive to purchase and require specialist programming skills to configure. The main purpose of the FPGA is to run the high-speed processing required to extract…

practicalwireless@warnersgroup.co.uk NO – it’s not a misprint. Although the call G6QA was originally issued nearly a century ago, the first picture, Fig. 1, really is G6QA and I think you’ll agree that it still looks a remarkably up-to-date operation. But G6QA is also the station in the next picture, Fig. 2, in the days when being a radio amateur still meant impressive 6ft racks of equipment – a far cry from the table-top transceivers found in most shacks today. The explanation, of course, is that the call is a re-issue, and I was keen to meet the present-day G6QA Lynda Jopson located in the Greater Manchester town of Kearlsley, near Bolton, to learn more about her introduction to amateur radio and how she came to acquire such a coveted callsign.…

SWAINS ISLAND DXPEDITION: Ronald PA3EWP sends information about this forthcoming activation of a rare one. After many years of preparation, it is time to go on a DXpedition to Swains Island. Our first attempt was 2 months before Covid, so we had to cancel our plans. After two years when the borders opened again but we had some trouble to charter a ship. But finally, it happens! From 4 to 17 of October we will be active from Swains with a team of ten operators from Germany, the Netherlands and the USA using the callsign W8S. The plan is to run four stations simultaneously 24 hours a day from two different camps. Two additional stations are available at each camp for the operator that still likes to operate or the…