Foundations Of Amateur Radio

Foundations of Amateur Radio Today I'm here to tell you that I'm in the process of writing a book, actually seven of them, and to be precise, there's more of editing than writing, since I'm putting together all of my podcast efforts over the past seven years. Nice how that works out, seven years, seven books. Most of the effort is in proof-reading my work. Do I spell radio amateur with capital letters, or not, do I use my word-processor to replace all occurrences of radio amateur without capital letters and what happens when I refer to them as radio amateurs instead? You get the drift, lots of minutia, consistency and every now and then a little edit to make a sentence make sense to a reader. As an aside, if I don't get distracted by life I'm planning to publish in the next week. The unexpected joy I'm getting from this experience is to read about my adventures and to remember some of the adventures that you have told me about, things I've been working on, events that you and I attended, contests, victori

Foundations of Amateur Radio The frequency you listen and transmit on in a modern radio is derived from a crystal master oscillator, in my case 22.625 MHz. That master frequency is multiplied and divided to determine the final frequency. To get to 2m you need to multiply by 6. To get to 70cm, multiply by 20. Similarly, to get to 40m, divide by 3. Any slight variation of crystal frequency has an impact. 100 Hz variation in the master oscillator causes the radio to be off by 600 Hz in 2m, or 2000 Hz in 70cm. The higher you go the bigger the error. This leaves us with two problems. If the crystal changes frequency over time, your radio wanders with that change which is especially noticeable on the higher frequencies. I've previously discussed how you can deal with the variation by correcting for temperature. The other problem is the actual absolute frequency. If the radio is set-up for a crystal with one frequency and you replace the crystal with a different one, how do you know what frequency you're actuall

Foundations of Amateur Radio You know when you walk down the street and you lift your foot and all of a sudden you realise that you stepped in something and now it's stuck to your shoe? I had that feeling during the week. Last week I mentioned that I had purchased a TCXO, a Temperature Controlled External Oscillator. Lowell NE4EB set me straight by pointing out that XO stood for crystal and that TCXO stood for Temperature Compensated Crystal Oscillator, which then lead me on a merry goose-chase trying to learn about all that. I mention this because while the stickiness on my shoe kept me busy, it also highlighted that I'm still a babe in the woods on a steep learning curve to knowledge with some roadblocks, diversions and potholes along the way. That reminds me, if you ever feel the urge to pull me up on something I've said, you can email me via my callsign at gmail.com. So, how does this Temperature Compensated Crystal Oscillator actually work? Without getting into the circuitry behind the scenes, as

Foundations of Amateur Radio Last week I spent a little time talking about the Weak Signal Propagation Reporters network, or WSPR, pronounced Whisper. You might remember that I set up my radio to receive these signals to see what I could learn. Turns out, I learnt quite a bit. I left the software running for a week. During that time my station reported 456 signals received with a total of 54 stations in 27 call areas. The longest distance 14,000 km, PC1JB in Veenendaal in the Netherlands who was using 1 watt. The best performance based on km per watt is R0AGL in Siberia, 10,000 km, with 2 milliwatt. Highest power heard, one station with 100 watts, but from a performance perspective, only just squeaks into the top 10 contacts. Typically stations used 5 watt or less. My 10m quarter-wave vertical antenna was pretty good in hearing things across all bands. I heard stations across the frequency range, from 160m through to 10m. It heard 1 station on 160m, VK7MF, using 5 watts, 3,000km away. The most prolifi

Foundations of Amateur Radio This week I'm going to talk about a Digital Mode you can use with any Amateur License, or even without an Amateur License. You can set-up your radio, hook it to a computer and the Internet and after installing some software, you can join the Weak Signal Propagation Reporters. So how do you start, what does it do and how can it help you? First of all, WSPR, pronounced Whisper, is a way of encoding information and transmitting it across the spectrum. At the other end a radio receives that signal, sends it to a computer where a piece of software attempts to decode and then log it. This Digital Mode, invented by Joe K1JT, is one of several modes that are gaining popularity across the Amateur Radio community because the beauty of this mode is that it's so unobtrusive that you're unlikely to actually hear it if you were to tune to a dedicated WSPR frequency. If you want to find out what your station can hear, you can set yourself up as a dedicated receive-only station and report yo

Foundations of Amateur Radio The other day a friend of mine asked a really silly question. How come when I point my YAGI at a direction for a station using the great circle, the signal is there but weak, but when I point it in a different direction, say 20 degrees away from the great circle, the signal improves? Being a good little Amateur, I responded with the logical explanation. Well, two things come to mind, one being that you're not pointing where you think you're pointing, that is, North on your antenna isn't North in reality, so when you point at the other station, it's not actually where you're pointing, and when you adjust, the antenna ends up in the correct direction. Another explanation I came up with is that the pattern of their YAGI isn't what they expect. There might be local factors that influence the pattern, putting weird distortions into their foot-print and making for "interesting" nulls where there should be signal, and vice-versa. That in turn started a whole conversation about dire

Foundations of Amateur Radio In the past I've talked about what kind of station I have, how I tend to operate and what kind of tools I use in my day-to-day running of an Amateur Radio station. This week I want to take a closer look at what I do when I participate in a contest. I remember fondly the first contest I ever set-up for, fondly as-in, "What was I thinking?" Let me set the scene. I'd previously been to a few stations that were participating in a contest. Some of those were in a club-shack, others were set-up portable in the field. For my first contest I was going to set-up my station in the field, so I needed to bring everything myself. Fortunately I was with friends, one with a camper-trailer, so I didn't need to bring a roof, or the kitchen sink, but I did bring pretty much everything else. My list included tables, chairs, antennas, radios, headphones, connectors, soldering iron, power-boards, extension cables, logbooks for paper logging, pens, clipboards, two computers, four spare batteries,

Foundations of Amateur Radio The way we connect our antenna to our radio depends on a number of different factors. If you've come through the ranks recently, like I have, it's probable that you've only ever considered using COAXIAL cable. It's a single conductor, surrounded by some type of insulator, which in turn is surrounded by a conductive shield, which is protected by another layer. There are variations where the shield has multiple layers, including layers of foil and braid, so-called quad-shield COAX, and there are variants that have several cores, sometimes two sets of COAX connected side-by-side and so on. In many ways, COAX is an invention of convenience, which has several compromises as a result, loss over distance, termination issues, twisting and deformation and others. It's compact, less susceptible to external interference, it's relatively easy to route to its destination and if you treat it well, it's easy to carry around, but it's not the only way you can feed an antenna. You may have com

Foundations of Amateur Radio The art of keeping your station organised and accessible has much to do with choosing wisely which bits to keep and which bits to throw. That's part of the story, but there are other aspects of organisation that will assist you. Rolling up coax is a skill that you need to learn. The over and under method of coiling cable is by far the easiest way to ensure that your coax stays healthy and happy without kinks and other distortions. Once you've coiled your coax, many amateurs use electrical tape to hold the coil in place for storage. This can be helpful, since it means that you'll always have a handy supply of electrical tape on hand for when the need arises, but an alternative is to use Velcro cable wraps which attach semi-permanently to one end of the coax and can be wrapped onto itself to make a loop around the coiled coax. Making a water-proof connection, for temporary use can be as simple as covering it in electrical tape. This isn't ideal and not permanent and water inside

Foundations of Amateur Radio Today I have a confession to make. Looking back it's clear that once your brain goes down a certain path, it's easier to follow the path than to find an alternative one. When I was growing up, above my bed, bolted to the wall were two brackets. On top of those brackets, secured with double-sided tape was a radio-cassette player. If you're unfamiliar with what an audio cassette is, don't worry, this is about the radio side of things and is from the days when Digital Music was not in wide use like it is today. I used this radio to listen to local stations, both on the AM and FM broadcast band, and I managed to even get to the beginning of the FM broadcast band where the police radio happened to be at the time in the country I was living. As years went by, that radio-cassette player was replaced with a radio tuner, then a combined amplifier tuner and I re-programmed it as I moved around the globe with new local stations filling up the quick select button memories. Over the last y

Foundations of Amateur Radio You've always been taught that VHF communications are line of sight and that the height of your antenna determines how far your 2m communication might go. So if I tell you that last week I spoke with a station that was 300 kilometres away on the 2m band you might be forgiven in thinking that I had managed to climb up most of the side of Mount Everest to around 7 kilometres so I could make my line-of-sight communications 300 kilometres away. I'll give you a hint. I was at my home, my house isn't on the side of Mount Everest and we were both using normal gear, nothing crazy, no amplifiers, no glitzy antennas, just the basics. So what's going on? There'ss a phenomenon called "Tropospheric Ducting" that comes and goes and if conditions are right, allows you to extend your line-of-sight communications to distances far beyond your imagination. So, what is this thing and how does it work? First of all, this is something related to the lowest part of the atmosphere, called the tropo

Foundations of Amateur Radio There is so much stuff associated with Amateur Radio that your family might be forgiven in thinking that your hobby is all about being in the middle of a junk-yard surrounded by the carcasses of disassembled gear, components, failed projects, obsolete equipment and scraps of wire, solder and countless screws, resistors and other bits and pieces that are just too valuable to dispose of. During the week I was given an incentive to reorganise my work-shop. I set aside an hour to do it and unsurprisingly, armed with 20/20 hind-sight, it took a day to complete. The upshot of this activity is that I can now walk into my work-shop, something which I couldn't last week, and to top it off, I could actually find things. I confess that I've reorganised my work-shop several times over the years, but each time I find that it returns to its natural state of junk everywhere. I have noticed that this state is taking longer and longer to achieve, which means that I am improving things, but not

Foundations of Amateur Radio The other day a fellow Amateur was relating their experience in the hobby. They spoke of interference, jamming, breaking in over the top of contacts and generally being hounded by special people who think it's their purpose in life to make life miserable for others. I have spoken in the past about similar experiences that I had with individuals jamming a weekly net that I've been hosting for new and returning hams, and occasions when I've been on-air with a special callsign with an individual yelling "pirate" at the top of their lungs in an attempt to get me off a particular band, even though I was operating in compliance with the license conditions. I've personally made complaints to the regulator about these occurrences, who then decided that being interfered with for over a year was something that the repeater owner should complain about. When they complained, they were told that there was not enough evidence, or some such excuse, I forget exactly the details, but the proble

Foundations of Amateur Radio The other day I was asked about what antenna should you get as your first one. This question is pretty simple, but the answer is likely much less so. You might recall that I've pointed out that we can prove you physically cannot build the ideal antenna, so by definition all antennas are compromises. You might also find yourself being bamboozled by claims about how an antenna is the perfect match across all or many frequencies. The same is true for a dummy load where the purpose is not to radiate at all. With that in mind and armed with a healthy dose of scepticism, you can now go hunting for the answer. On my journey through this minefield of mysticism I went from a self built wire vertical on a squid pole with a 16 radial ground plane and an electronic antenna coupler, through a set of purchased single band verticals, a wire dipole, a wire delta loop, a Buddi-pole, a magnetic loop, a multi-tap vertical, and many others along the way. Some of those antennas were bought, othe

Foundations of Amateur Radio The other day I was browsing through the Amateur Radio Syllabus for Foundation Licensees, as you do, you know, when you're bored out of your mind, or in my case, looking for a topic to talk about. So, I came across this interesting point, if you want to look it up, point 2.2 of the Foundation Syllabus. It states that in order to attain your Foundation License in Australia you must: "Recall that an Amateur Licence primarily authorises the operation of an Amateur station for self-training in radio communications, inter-communications between Amateurs and technical investigations into radio communications." You might hear that and think, ok, so what's your point? Simple really. As an Amateur Radio community we have come to collectively understand that in order for you to do anything in the realm of building or research, you need to hold more responsibility and that if you're on the so-called bottom rung of Amateur-dom, you really are only a button twiddler, appliance operator and

Foundations of Amateur Radio Previously I've explained how Radio-teletype or RTTY works from a technical perspective. If you recall, it uses a technique called Frequency Shift Keying, or FSK to encode digital information. It does this by transmitting a carrier across two alternating frequencies, allocating one as a SPACE and the other as a MARK, or as a binary 0 and a binary 1. There are several other ways of encoding information and today I'm going to look at Phase Shift Keying, or PSK, which I find humorous, because Phase is spelled with a P, but it sounds like an F, which links the FSK and PSK together, but then I've always had a strange sense of humour. Imagine if you will a sine wave. It's the one you learned in high-school, nothing sophisticated about it, just keeps going up and down over time. Now imagine another one. Also going up and down over time. If these two sine waves are synchronised, going up and down at the same time, the difference between them is 0. If one of the sine waves is going up,

Foundations of Amateur Radio The continued discussion in our community about Digital Modes got me thinking about what a Digital Mode actually is. At the most fundamental level, it's about encoding information into discrete chunks to exchange information. Morse Code is an example of a Digital Mode, made up from combinations of dits and dahs. If you change frequency whilst sending dits and dah's you invented RTTY or Radio-teletype. There are two frequencies involved, 170 Hz apart, where the lower frequency is the SPACE frequency and the upper frequency is the MARK frequency. If someone gives you a RTTY frequency, they're talking about the upper frequency. Instead of using Morse Code to send messages, RTTY uses 32 different codes, 5 bits, to exchange information. This isn't enough for the entire alphabet, with digits and punctuation, so two of the codes are used to swap between Letters and Numbers. Some radios can change frequency between the lower SPACE and upper MARK frequencies in a single transmission. T

Foundations of Amateur Radio Having a Digital Mode in your shack appears to be a special privilege, at least in some parts of the world. If you'd like to learn all there is to do with using a Digital Mode you need to pay attention and I'll share the secret, it won't take long. If you want to distinguish yourself as a Digital Mode Diva, you need to know that Morse, RTTY, FSK and PSK are digital modes and you must also remember that the bandwidth of a data transmission is dependent on speed and mode. At this point you've covered all the syllabus requirements for holding a Standard License in Australia in relation to operating a Digital Mode. If you want to climb the Mountain of Digital Mode Magic, you need to remember two acronyms, FEC or Forward Error Correction and ARQ or Automatic Repeat Request. You also need to remember four numbers, 31 Hz for PSK31, 250 Hz for RTTY, 730 Hz for Packet Radio and 300 Hz for FSK. And if you want to get really fancy, I should point out that there are several versions of ea

Foundations of Amateur Radio The other day a whole new world opened up to me when I came across the idea that Voltage is the same as Force and Current is the same as Velocity. It all came about when I installed two mechanical filters into my radio. You heard that right, in my shiny solid-state radio, I added moving parts! The purpose of this was to improve the way the radio ignores unwanted signals and as a result has an easier time hearing what it is you really care about. The radio already has filters built-in, but mechanical filters offer a cleaner output with less distortion across a wider range of temperatures. Another way is to say that - mechanical filters have a much higher Q. Think of a pendulum swinging through oil, it's losing lots of energy for every swing and has a low Q. The same pendulum swinging through air retains most of its energy and has a high Q. The same is true for mechanical filters, less energy loss, better reproduction, better outcome for the things you want to keep and hear. So

Foundations of Amateur Radio For the most part of my Amateur Radio life I've been an active contester. I have spoken about why I love contesting and why I think it's an important aspect of this amazing hobby. Today I want to talk about how contests are run, specifically how complaints are handled and how we could improve. I must at this time acknowledge that organisers are volunteers, just like many other Amateurs, giving of their free time, in this case, to manage and score a contest. Like much volunteering it's an invisible, sometimes thank-less and unenviable task, often akin to herding cats. To set the scene, a contest is an organised activity run by one or more people or groups that has a published set of rules, a set of aims and objectives as well as the mechanics of things like on-air conduct, point scoring, etc. A contester who decides to participate in a contest is expected to read the rules, abide by them and conduct themselves in an appropriate manner, that is, keep accurate logs, follow the lo