Tabla de contenidos para December 2023 en Practical Wireless

Given that there was no National Hamfest this year (one is promised for next year, apparently back at Newark with the contract already signed), it was great to attend the RSGB Convention and catch up with friends old and new. One of the first I met was PW regular columnist and contest organiser Colin Redwood G6MXL who was attending for the first time and I asked him for his impressions – see his report below on the various lectures. Indeed, it was good to catch up with many of our authors such as Mike Richards G4WNC, Gwyn Griffiths G3ZIL and Roger Cooke G3LDI along with regular contributors such as Victor Brand G3JNB. The event was well organised as usual with David G7URP and Tammy M0TC from the Norfolk Club along…

The wide-ranging new proposals from the UK’s communications regulatory body Ofcom have been the subject of club discussions all over the UK over the past few months. It was all the more appropriate and timely, therefore, that my club – the Warrington Amateur Radio Club based in Grappenhall, Cheshire – recently received a welcome invitation from Ofcom’s Spectrum Assurance Team to visit their station at Baldock, Hertfordshire for a guided tour. The Club already had close and friendly relations with Ofcom. A year ago we were contacted by the Spectrum Assurance team who were developing a staff awareness program for newer Ofcom engineering members. The Ofcom local regional office, based in Warrington, wondered if our Club would consider assisting them by providing access to a working amateur radio station in…

Welcome to the December HF Highlights and a very Merry Christmas or Happy Hanukkah to all readers. Neil Clarke G0CAS sent in his regular 28MHz beacon report for the month of September: This summer’s Sporadic E season appears to be somewhat down on recent years and September continued with a lower number of beacons heard compared with the same month last year. Some of the more regular beacons were DL0IGI 28205, heard on six days, and IQ8BB 28260 was heard on 14 days. During the height of the season numerous beacons were logged on more than 20 days a month but were down into single figures in September. For example, IZ8RVA 28240 was heard every day in June but only on four days during the entire month of September. There…

It was early morning when Natalie arrived at the lab. Jeff as usual was already there with a cup of tea while he browsed his latest copy of Practical Wireless. “Morning Jeff”, Natalie said as she walked to her desk. “Morning Natalie, good day at college?” Jeff replied. “Yes”, Natalie went on. “We covered capacitors”. “OK”, Jeff mused, “So I suppose we’ll be spending lunchtime talking about them”. “Yes please”, Natalie replied, “Archie says that he is going to spend a couple of weeks talking about passive components that work differently for alternating current than they do for direct current”. Lunchtime arrived and after they’d consumed their lunches, Natalie wandered over to Jeff’s desk. “Right, let’s talk capacitors shall we”, said Jeff. “Actually, there is quite a lot to talk…

This really midget receiver. measuring only 1 3/8in x 7/8in x ¼in, or rather less than half the size of a matchbox. has been made possible by the production of really midget components. In this Lilliputian space is accommodated the 3-transistor, 4-stage. T.R.F. circuit using resistance capacity coupling. The power supply is one of the comparatively new mercury cells only 7/16in. in diameter and 3/16in. high. It should run the set for about 2½ months if used for an hour each day. The set makes use of permeability tuning and. although designed for use with a deaf-aid earpiece, we found under lest that it worked a small speaker at a comfortable volume. It can be built for about £4. It incorporates the subminiature transistors now readily available at a reasonable…

PW 70MHz CONTEST RESULTS: Colin Redwood G6MXL has the results of the 2023 PW 70MHz Contest. A REVIEW OF THE AMPRO MOBILE WHIP RANGE: Vince Lear G3TKN takes a look at this popular range of antennas. ARECIBO & SAM HARRIS W1FJZ: Ray Howes G4OWY/G6AUW explores some history of the classic Arecibo radio telescope. MORSE BEFORE RADIO: Tony Smith G4FAI concludes his account of how Morse was sent and received before the advent of wireless. THE SKELETON SLOT ANTENNA HF - 440MHz: Ian Dilworth G3WRT describes modelling and building skeleton slot antennas for HF, 40, 50, 70, 144 and 433MHz, resulting in an exceptionally low profile omni 1dBd vertically polarised antenna. LAB TUTORIAL: Jeff completes his explanation of capacitors, begun in the December issue. SEASONAL QUIZ: We have our usual seasonal…

The much publicised incident on 28 August and succeeding days, when the UK’s en route air control traffic control system virtually shut down, has since been explained in an official report. At 0832 on that date, the NATS ATC system received a flight plan for a transatlantic aircraft that was due to overfly the UK. The flight plan had been handed on routinely by Eurocontrol’s Integrated Initial Flight Plan Processing System. Eurocontrol, based in Brussels, is the pan-European organisation that coordinates air navigation. Normally the NATS system extracts the relevant UK portion of the flight and presents it to controllers. However, data in the flight plan triggered the shutdown of the entire system and its back-up (technically, they were both put into ‘maintenance mode’). The report says the system ‘was…

Over the years I have covered a number of award schemes, including Worked All Britain (WAB), Summits on the Air (SOTA), HUMPS/HEMA, World-wide Fauna and Flora (WWFF), Parks on the Air (POTA) and Castles on the Air (COTA). This month I am looking at several award schemes based around lighthouses. Several schemes? As with many of award schemes based on ‘things’ on the air, there is more than one award scheme plus a couple of lighthouse weekends! They each have their own characteristics, with their own definitions of lighthouses and quite different numbers of lighthouses, Table 1. For the purposes of this article, I will use the term ‘lighthouse’ to cover whatever is in scope of the various award schemes, some of which include lightships, for example. World Lighthouse on…

Following the conclusion of our in-depth coverage of the Coronation in 1937 of King George VI and Queen Elizabeth, we now focus on the Coronation of the late Queen. The engineering planning to cover the Coronation of Queen Elizabeth II on Tuesday 2 June 1953, began twelve months before the event. The general responsibility for organising the main broadcasts in sound and by television was devolved entirely to the two Outside Broadcasts departments concerned. As the scheme took shape, however, it became apparent that virtually every BBC department would have to be involved and coverage would be a massive technical operation. For the Coronation of King George VI in 1937, there were 17 sound commentary positions in all, including ten for overseas services. In 1953, the plan provided for 95…

In this month’s column I am examining three small projects I have recently undertaken in the shack. These are the construction of a small Field Strength Meter, and implementation of two switching solutions, the first for routing my rig’s audio output to a Daiwa audio filter and shack speaker, and the second for matching my favourite CW paddle to multiple rigs. A Field Strength Meter Let us start with a Field Strength Meter (FSM.) Such a meter can either be a passive or an active device, determined by whether or not you include an amplifier stage that requires a power source. A passive device, however, requires no power source other than the RF field that it is seeking to display on a meter. In my case, I wanted a small…

Rediscovering an old blueprint Dear Don, I am now nearly retired after more than 40 years working in the radio communication / long range radar field. I have seen changes from valves to transistor to IC and now SDR. I have worked a lot on ex-RAF/IAL equipment, high power HF Tx, aerial farms, SSAB and RTTY, and later on radars primary and secondary. I have been a radio amateur since 1985, callsign 9H1BP. My career sparked from my father’s PW magazine, which dates back to around 1958, all nicely bound in a green hardbound with the year in the front. The story behind this blueprint is that when I was 12, my father and I started building a topband transmitter using the OC 71 and OC45, but the range never…

A friend called me to say that the auto tuner at his /A alternative location had finally passed away and that he was looking for a low-cost replacement. Did I know anything about the Chinese made AT-100? I have to confess that despite being something of a hoarder and possessing several automatic QRP to QRO matching units from various manufacturers, that this was a new one for me. Yes, I was aware of it and had seen it many times in a number of versions on-line and in various forms but never used one. After a little discussion and seeing what looked like a very attractive price online (caveat emptor) I couldn’t resist in joining my friend in pressing the, ‘buy it now’ button just to find out if it…

We’ve been expecting the Raspberry Pi 5 for a long time but, like many projects, the global component shortage has hampered work on the new Pi 5. Unusually for the Raspberry Pi team, the Pi 5 was given a pre-launch announcement, with first deliveries expected about four weeks later. All previous launches have been something of a surprise, with the product available immediately. I suspect this approach is an attempt to gauge and manage the demand and hopefully avoid the disappointment of previous launches where the product sells out quickly. I’m sure the demand for the Pi 5 will be huge, especially as it has many mouthwatering features. I’m still awaiting delivery at the time of writing, but I can tell you how its new features will impact its use…

It really is amazing how often old Morse keys seem to crop up. I was sent the pictures by a friend of mine Pete G0FVG. Apparently, this key was found when clearing out the possessions of somebody who had died. He was not a radio amateur, but this key was found in his shed. Pete would be interested if anybody could identify it or suggest where it came from. The pictures show several different views. It is rather dirty after being stored in a shed, but it does look to be very unusual. According to the label, not totally legible, it originated in London. If anybody has any details, please email Pete direct: peter.fvg@gmail.com Procedural signals again Tony G4NBS sent the following: “Changing modes to CW, I read your comments…

How was Morse sent and received, and what did it sound (or look) like, before wireless was invented? Samuel F B Morse’s first experimental transmitter of 1832 was called a Correspondent. This sent numbers, derived from a numbered dictionary of words or phrases, which were read at the receiving end by looking them up in a similar book. He called his receiver a Register. He didn’t think in terms of dots and dashes but considered the signals to be made up from dots (short or long) and spaces. The Register drew a series of Vs with a pencil, on a moving strip of paper from which the numbers could be determined. The numerical code was replaced in 1837 by an alphabetical dot-dash code, also sent and received on the original…