Foundations Of Amateur Radio

Foundations of Amateur Radio When you start playing with software defined radio, you're likely to begin your journey using something with a display that shows you a lovely waterfall, gives you a way to pick out a frequency, decode it and play it over your speakers all over the house. Likely your first effort involves a local FM radio station. These graphical tools come in many and varied forms available on pretty much anything with a display. Tools like SDR#, cuSDR, fldigi and WSJT-X. That can be immensely satisfying as an experience. Underneath the graphics is software that is essentially translating an antenna voltage to a sound, in much the same way as that happens in an analogue radio. There are the parts that get the signal, then they get translated and filtered, translated some more, decoded, and eventually you have sound coming from your speakers. During the week I caught up with a fellow amateur who pointed me at the work of Andras HA7ILM who for a number of years has been quietly beavering away m

Foundations of Amateur Radio In 1958 The Kentucky Engineer published an award winning student article by Copthorne "Coppie" MacDonald. He described a Slow-Scan T.V. System for Image Transmission. If you get the opportunity, have a look for the link on his archived home-page which you can find from the Wikipedia SSTV page. The purpose of this narrow band television idea was to be able to send images using cheaper equipment and less bandwidth than normal television. The idea caught on and it's still in use today. In 1959 the idea of slow scan tv was used by the Luna 3 mission to transmit images from the far side of the moon. The NASA Apollo program also used SSTV to transmit images from Apollo 7, 8, 9 and from the Apollo 11 Lunar Module. In 1968 SSTV became a legal mode for radio amateurs in the United States. The International Space Station regularly uses SSTV to send images to radio amateurs across the globe. The version of SSTV in use by radio amateurs today is different from the earlier grainy black a

Foundations of Amateur Radio My radio shack consists of two radios, identical, well, in as much as that they're the same model, a Yaesu FT-857d. Their memories are different, their microphones are different, but both of them are connected via a coaxial switch to the same VHF and UHF antenna. One of them is also connected to a HF antenna. Let's call these two radios alpha and bravo. Alpha is used to host F-troop and play on the local repeater. Bravo is used to do HF stuff. It's also connected to a computer via a serial cable, called a CAT cable, Computer Assisted Tuning, but really, a way to control the radio remotely. The audio output on the rear of the radio is also connected to the computer. These two connections are combined to provide me with access to digital modes like PSK31, WSPR and SSTV, though I haven't actually yet made that work. The computer itself is running Linux and depending on what I'm doing on the radio some or other software, often it's fldigi, a cross-platform tool that knows about m

Foundations of Amateur Radio Yak Shaving ... Not every adventure gives you an outcome. Today started with reading a thank-you email from a listener who shared their activities and wanted to express their gratitude for encouraging them to get on air and make noise. That in turn prompted the question on the country of origin of that listener and did I know where all my listeners were? For the past few hours I've been attempting to answer that seemingly simple question. Aside from using the opportunity to make an attempt at mapping the distribution of amateurs in Australia, which on the face of it is a trivial exercise, consisting of extracting the postcode from each registered amateur and then putting those on a map. Only the postcodes are not actually single points. They're boundaries defined by Australia Post and they're copyrighted. Not only that, they change. To access them, you have to pay the Post Office. If you want to combine a postcode with a population density, so you can see where amateurs are r

Foundations of Amateur Radio In my ongoing software explorations I've discussed that Software Defined Radio or SDR is a fundamentally different way of dealing with radio. It's been in use across non-amateur circles for decades. Your mobile phone has an SDR on board for example. The original term of "digital receiver" was coined in 1970, "software radio" was coined in 1984 and in 1991 Joe Mitola reinvented the term "software radio" for a planned mobile phone base station. So, this idea has been around for half a century and in amateur radio this idea is also catching on. You can buy a few pure SDR devices today, some hybrid ones, or you can begin to experiment in a more indirect manner using your traditional radio and a computer. One of the things that sets this idea of a software defined radio apart from anything we've done so far is that the bulk of the signal processing is done in software. That sounds obvious, but it's really not. One of the impacts of this idea is that you can improve your radio comm

Foundations of Amateur Radio Contesting is a fun way to learn about amateur radio. It tests your skill, your station, your patience and your ability to change approach at a moments notice. For those reasons alone it's an activity that I recommend you have a go at. For me it's also about self-improvement. With each contest, can you make better use of your station, can you learn more about your radio, about bands, about conditions and ultimately become a better operator. I know that there are individuals who keep telling me that giving out signal reports of 5 and 9 isn't helpful, to them I say, try it in a contest setting and see what else you learn. When you start out contesting you'll quickly come across two terms, technically three, that need some explanation. The terms are Run, Search and Pounce, though the last two come as a matched pair. The essential bit of information is that when you're on a Run, or Running, you're calling CQ and responding to other stations. You essentially sit on a frequency for

Foundations of Amateur Radio It's the morning after the day before. I've been calling CQ for 24 hours and for the first time in my life after a contest I still have my voice. That in and of itself is novel. I also don't have ringing ears, that's a blessing. I have learnt heaps and had fun doing it. I made contacts and I heard stations across the globe and I did it all from the comfort of my shack chair. Before I dig in and expand, the contest I just completed ran for 24 hours. I didn't sit at my radio for all of it, nor was my radio on for all of it. I managed to have lunch, dinner, desert, breakfast and morning tea. I snuck in a few naps and I managed to help with bringing in the shopping. My station did not transmit unattended at any time in case you're wondering. My setup consisted of a little 11 year old netbook computer running the current version of Debian Linux and the heart of this adventure, the software called fldigi. The computer is connected to my Yaesu FT-857d via three cables, well, two and a

Foundations of Amateur Radio When you start playing with radio your first interaction is likely to be voice. It could be SSB, AM, FM or something more recent like FreeDV or DMR. Your next challenge is likely going to be a digital mode like Morse Code, Radio Teletype or my recommendation for your first adventure, WSPR or Weak Signal Propagation Reporter. I've previously discussed WSPR, today I would like to look at Radio Teletype or RTTY. It's a digital mode that allows you to send and receive free-form text. It's a mode with a long and illustrious history and it's a good next step after WSPR. The way it works is that using an alphabet made up from two tones, information is transmitted, one character at a time at a specific speed. The code that describes the alphabet is called the Baudot code, invented by Jean-Maurice-Emile Baudot in 1849. In computing terms it's a 5-bit alphabet and in amateur radio it's traditionally sent at 45.45 baud or bits per second, in case you're wondering, named after the very sam

Foundations of Amateur Radio When I came across amateur radio nearly a decade ago I did a course, passed my test and got licensed. At that point I didn't have any equipment, didn't know about any, hadn't touched anything, other than the radio in the classroom, and had no idea about what to buy and how to choose. So, instead I asked the friend who introduced me to the hobby, Meg, at the time VK6LUX, what radio to get. I asked her what was the second radio she ever got because I figured that I'd get very disappointed with the first one in short order. She explained that there were plenty of brands to choose from and that each had their own champions. Just like the perennial choice between Ford and Chevrolet, Apple vs Microsoft, Tea vs Coffee, you'd end up with one radio and be told by someone in a different camp that you chose the wrong one. Her advice, which is just as solid today as it was a decade ago, was to buy something that people you knew had, so whilst you're learning there'd be someone nearby who c

Foundations of Amateur Radio The other day day I managed my first DX contact using a new mode, FT8. It wasn't very far away, all of 2600 km or so, but it evoked memories of my first ever on-air DX contact nearly a decade ago. I should say thank you to YD3YOG for my 15m contact, fitting because my first ever was also on 15m as I recall. Unfortunately I never did log my first. Recently a friend asked me how the two compared. 15m and logging aside, there's a lot of similarities, even though I'm a more experienced operator today when compared to when I made my first ever contact. The preparation and the building anticipation is what made the contact all the sweeter. A while ago I managed to connect the audio of my radio to a computer. This is pretty much the first step in starting to use digital modes. Essentially many common digital modes use an SSB transmission to generate and receive audio that in turn contains digitally encoded information. There are hundreds of modes like this, from PSK31 to RTTY, WSPR

Foundations of Amateur Radio When was the last time you told anyone anything about your hobby? What about someone who isn't also an amateur? Have you ever considered why there is a perception that our hobby is dying, why it's running out of people, why we struggle to get air-time in mainstream media, why attracting new members is hard and why there is a very narrow range of understanding about what our hobby is, what it does and how it's relevant in the world today? I'm a radio amateur. So are you. You might not be licensed yet, but the fact that you're here right now indicates a willingness to understand and learn, to participate and question. Those qualities are the fundamental building blocks that make up a radio amateur. I'm also a self-employed computer consultant, a radio broadcaster, an interviewer, a software developer, a public speaker, a blogger, author, publisher and a partner. My friends include people who are process managers, astronomers, gynaecologists, mariners, tow truck drivers, communi

Foundations of Amateur Radio One of the recurring questions in this hobby, technically outside this hobby, asked by people who've not yet, or have only just been bitten by the bug, is: "What's the point of this hobby?" In some ways I too have asked this question, though for me the answer came within a few months of learning that amateur radio exists. In response to others asking this I've also made meagre attempts to answer this question with varying degrees of success and satisfaction. The typical responses are things like: there's a thousand hobbies inside amateur radio, it's about the communication, about the camaraderie, about climbing and hiking, about technology, science, physics, electronics. The truth is that this is just a fly-over view of what it means to have this as your hobby. It occurs to me, having now been licensed for a little while, I can actually express a little more clearly what this hobby has given me. At a basic level, I now know what the front of a TV aerial is and how Wi-Fi is at

Foundations of Amateur Radio The hobby of Amateur Radio is essentially one of experimentation. Within our community we endlessly build things, from amplifiers to Yagis and every letter of the alphabet in between. With every experiment we grow the amateur radio sphere of influence just a little bit. As our hobby is evolving into Software Defined Radio, or SDR, the homebrew aspect of our community is also changing bit by bit and as a result, homebrew today is just as likely to be based on software as it is in hardware. Unlike the physical world where you need to source and buy components, design a circuit, build it, test it and then put it in a box, in the software realm you can get started with the computer that is more than likely within reach right now. Recently I took delivery of a new SDR, an ADALM Pluto. It's essentially a Linux computer, FPGA and transmit capable SDR in a small box. I bought it specifically for the purpose of experimentation. One of the first things I did with this device was instal

Foundations of Amateur Radio Every week I run a net for new and returning amateurs. A variety of people join in with varying degrees of skill, knowledge and number of birthdays. One of the regular things I say during that net is that if I'm not acknowledging you, it's because I cannot hear you. I then start a spiel about repeater offsets and give some examples, but what is it really and how does it work? As you might recall, a repeater is a radio, generally located somewhere useful, like on a hill or tall building, that offers the ability to talk to other amateurs who are not within range of your radio. For bands like 2m, 70cm and 23cm, generally speaking, contacts are line-of-sight. If you're standing on a hill, you can talk to more people because your line of sight is further away. This is also why you can talk to the International Space Station with a hand-held, since it's in your line-of-sight, at least some of the time. A repeater acts as a line-of-sight extender. If it can see both you and another

Foundations of Amateur Radio The single most discussed topic in amateur radio is that of antenna design, that and medical procedures on 80m, but I kid. Previously I've discussed the notion that all frequencies are on-air all the time and that your traditional radio uses much of its electronic circuitry to filter out all the things you don't want to hear. Parallel to that is the concept that you tune your antenna to be resonant on a particular band or frequency. As amateurs we might look for a wide-band antenna that makes it possible to use our radio across several bands. We often construct our antennas to be multiple harmonics of a band so we can have access to more spectrum without needing more physical antennas. None of this is new and as an amateur you'll likely spend the rest of your days improving your antenna situation, or at least talking about it, if not outright bemoaning the lack of antenna space, family approval, budget or some other excuse. As I started my journey into Software Defined Radio a

Foundations of Amateur Radio The day came to pass when all my set-up and configuration was going to culminate in the moment of truth when I enabled TX on my WSPR mode station. Before I tell you of my experience, I should give you a little bit of background. A few weeks ago I managed to erect a HF vertical at my home or QTH. That in and of itself was news worthy, well at least to me it was, since it was the first time since I became licensed in 2010 that I had actual real all-band HF capability at home. Last weekend I ran some RG6, yes, 72 Ohm Quad Shield, low-loss coaxial cable, from my antenna, through the roof, into my shack. I was thrilled. Immediately set about getting my HF station up and running. This involved installing WSJT-X, a tool that allows you to do weak signal work, perfect for when you're a low power or QRP station like me. I've previously reported using WSPR, Weak Signal Propagation Reporter on a Raspberry Pi and a dongle, but this time I was using my Yaesu FT-857d. Reports were coming i

Foundations of Amateur Radio The other day I was getting ready to go out when rain started pelting down. Not unexpected in this part of the world at this time of year but inconvenient for my plans. I didn't particularly want to carry an umbrella and the thought of wearing a rain hood brought back memories of water trickling down my back. For reasons I'm not quite sure of, my eye fell on my hat on its hook at the door. The hat I wear in the heat of summer to keep my brain from frying, the hat I use whilst camping with my amateur radio friends, the hat I've worn whilst loading massive hay bales with a tractor and the hat I've worn swimming in the Ord River - well, a descendent, third generation if I remember correctly. I shook my head in disbelief, after donning my raincoat, put my trusty Akubra Territory on my head and stepped out into the rain. Perfect. Kept me dry, kept my glasses clear and no drips down my back. You may well wonder what this has to do with radio and that's a fair question. I will prefa

Foundations of Amateur Radio Much of the operation that I've done as a radio amateur is conducted in the field. That is, I tend to either drive my car to a location, or go out with friends and set-up camp to play. After you do this for a while you start to notice the things that you look for in an operating position. The very first one is accessibility. That is, how easy is it to get there? It's fine coming up with the ultimate location, but if it's an hour's drive away and you've only got an hour to play, you'll spend all your time getting there and you'll be home late. By contrast, for field days lasting several nights, I've regularly driven more than a hundred kilometres to find the spot, sometime much more than that. The point is that the accessibility changes depending on your available time. The journey to the location can be just as much fun as the destination itself. How long you plan to be there will determine what antennas you might want to set-up. If you're there for an hour, you'll likely use

Foundations of Amateur Radio If you've ever used a spray can of WD-40, you might have wondered what the name means. It stands for "Water Displacement, 40th formula". In my time as a radio amateur I'd never stopped to think what the RG in RG-58 stood for. Turns out that it too has a meaning, "Radio Guide", though I have found some interesting alternative descriptions where the G stood for Government. This radio guide, really a transmission line, gets a signal from point A to point B. Depending on how you construct that transmission line determines what you'll get at the other end. Coaxial cable or coax is a length of cable made from several components. There's the outer layer or jacket, that protects the cable from electrical shorting, U/V deterioration and water ingress which causes all manner of problems. Inside that is an electrically conductive shield that forms one half of the transmission line, inside that is a dielectric, essentially a separator or insulator between the shield and the inner most, or

Foundations of Amateur Radio During the week I climbed on my roof and installed a base antenna for the 2m and 70cm band. The antenna is a Diamond X-300N. It's 3 meters tall, has a gain of 6.5 dB on 2m and 9 dB on 70cm. I've owned it for just under eight years and this week I finally took it out of the box and installed it. I know, I know, in my defence, you shouldn't rush these things. Truth is, until this week I really didn't have a realistic way of installing it. Several factors needed to come together. Some of them trivial, others less so. In the end, the antenna is now installed on my roof, connected via coax through my roof to my radio. Now before we get all excited about what that means, let's compare my previous outdoor setting to the current one. Today I'm using LMR-400 coax, 30 meters of it. Previously I used RG-58, but only 20 meters of it. From a coax perspective, even though I increased the length by 30%, my loss actually went down, on 70cm it went down by over 4 dB. If you recall, 3 dB loss