Foundations Of Amateur Radio

Foundations of Amateur Radio One of the things about amateur radio that I find intensely fascinating and to be honest sometimes just as frustrating, is that you don't know what the outcome of an experiment might be at any one time. Not because you cannot control the experiment, or because you don't know what you're doing, but because the number of variables involved in most meaningful amateur radio experiments is pretty much infinite. I've spoken about this before, the idea that if you were to make a simple dipole antenna and fold the ends on each other, you'd have infinite variation in antennas with just a so-called simple antenna, since you can vary the shape of it in an unending variety of ways. The other day I was doing an experiment. An amateur radio one to be sure, but I was doing this within the realm of computing. I have been playing with digital modes for some time now and along the way shared some of what I've learnt. It occurred to me that I've been assuming that if you had the chance to follow

Foundations of Amateur Radio So, there's nothing on TV, the bands are dead, nobody is answering your CQ, you're bored and it's all too hard. You've run out of things to try, there's only so many different ways to use the radio and it's all too much. I mean, you've only got CW, AM, SSB, FM, there's Upper and Lower Side-band, then there's RTTY, the all too popular FT8, then there's WSPR, but then you run out of things. I mean, right? What about PSK31, SSTV, then there's AMTOR, Hellschreiber, Clover, Olivia, Thor, MFSK, Contestia, the long time favourites of Echolink and IRLP, not to forget Fusion, DMR, D-STAR, AllStar, BrandMeister or APRS. So far I've mentioned about 20 modes, picked at random, some from the list of modes that the software Fldigi supports. Some of these don't even show up on the Signal Wiki which has a list of about 70 amateur modes. With all the bands you have available, there's plenty of different things to play with. All. The. Time. There's contests for many of them, so once you've go

Foundations of Amateur Radio Over the past little while I've been experimenting with various tools that decode radio signals. For some of those tools the signals come from space. Equipment in space is moving all the time, which means that the thing you want to hear isn't always in range. For example. The International Space Station or ISS has a typical orbit of 90 minutes. Several times a day there's a pass. That means that it's somewhere within receiving range of my station. It might be very close to the horizon and only visible for a few seconds, or it might be directly overhead and visible for 10 minutes. If it's transmitting APRS on a particular frequency, it can be decoded using something like multimon-ng. If it's transmitting Slow Scan TV, qsstv can do the decoding. I've done this and I must say, it's exciting to see a picture come in line-by-line, highly recommended. The National Oceanic and Atmospheric Administration or NOAA, has a fleet of satellites in a polar orbit that lasts about 102 minutes

Foundations of Amateur Radio When you begin your journey as a radio amateur you're introduced to the concept of a mode. A mode is a catch-all phrase that describes a way of encoding information into radio signals. Even if you're not familiar with amateur radio, you've come across modes, although you might not have known at the time. When you tune to the AM band, you're picking a set of frequencies, but also a mode, the AM mode. When you tune to the FM band, you do a similar thing, set of frequencies, different mode, FM. The same is true when you turn on your satellite TV receiver, you're likely using a mode called DVB-S. For digital TV, the mode is likely DVB-T and for digital radio it's something like DAB or DAB+. Even when you use your mobile phone it too is using a mode, be it CDMA, GSM, LTE and plenty of others. Each of these modes is shared within the community so that equipment can exchange information. Initially many of these modes were built around voice communication, but increasingly, even th

Foundations of Amateur Radio This podcast began life under the name "What use is an F-call?" and was renamed to "Foundations of Amateur Radio" after 206 episodes. To mark what is effectively this, the 500th episode, I considered a retrospective, highlighting some of the things that have happened over the past decade of my life as a radio amateur. I considered marking it by giving individual credit to all those amateurs who have helped me along the way by contacting me, documenting things, asking questions, sharing their experiences or participating in events I attended. Whilst all these have merit, and I should take this opportunity to thank you personally for your contribution, great or small, to amateur radio, to my experience and that of the community. Thank you for making it possible for me to make 500 episodes, for welcoming me into the community, for being a fellow amateur. Thank you. During the week I received an email from Sunil VU3ZAN who shared with me something evocative with the encouragement to

Foundations of Amateur Radio Amateur radio is a living anachronism. We have this heady mix of ancient and bleeding edge, never more evident than in a digital mode called Automatic Packet Reporting System or APRS. It's an amateur mode that's used all over the place to exchange messages like GPS coordinates, radio balloon and vehicle tracking data, battery voltages, weather station telemetry, text, bulletins and increasingly other information as part of the expanding universe of the Internet Of Things. There are mechanisms for message priority, point-to-point messages, announcements and when internet connected computers are involved, solutions for mapping, email and other integrations. The International Space Station has an APRS repeater on-board. You'll also find disaster management like fire fighting, earthquake and propagation reporting uses for APRS. There's tools like an SMS gateway that allows you to send SMS via APRS if you're out of mobile range. There's software around that allows you to post to Twit

Foundations of Amateur Radio When you join the community of radio amateurs you'll find a passionate group of people who to greater and lesser degree spend their time and energy playing with radios in whatever shape that takes. For some it involves building equipment, for others it means going on a hike and activating a park. Across all walks of life you'll find people who are licensed radio amateurs, each with their own take on what this hobby means. Within that community it's easy to imagine that you're the centre of the world of radio. You know stuff, you do stuff, you invent stuff. As a community we're a place where people dream up weird and wonderful ideas and set about making them happen. Radio amateurs have a long association with emergency services. When I joined the hobby over a decade ago one of the sales pitches made to me was that we're ready to be part of emergency communications. In some jurisdictions that's baked into the license. There was a time when a radio amateur was expected to be read

Foundations of Amateur Radio For decades I've been playing with every new piece of technology that comes my way. In amateur radio terms that's reflected in, among other things, playing with different antennas, radios, modes and software. One of the modes I've played with is slow scan television or SSTV. It's an amateur mode that transmits pictures rather than voice over amateur radio. A couple of months ago a local amateur, Adrian VK6XAM, set-up an SSTV repeater. The way it works is that you tune to the repeater frequency, listen for a while and when the frequency is clear, transmit an image. The repeater will receive your image and re-transmit it. It's an excellent way to test your gear and software, so I played with it and made it all work for me. In 2012 I was part of a public event where local schools participated in a competition to have the opportunity to ask an astronaut on board the International Space Station a question as part of the City of Light 50th anniversary of John Glenn's first orbit. Th

Foundations of Amateur Radio The other day I wanted to know what kind of communication was possible between my station and the station of a friend of mine. We want to do some experiments and for that to be possible, we need to have a reliable communication channel. Traditionally you would get in touch with each other and attempt to find a suitable frequency on a band to make a QSO or contact. That generally involves picking a band, then tuning around the band, finding a frequency that's not in use, then listening, asking if the frequency is in use, then telling your friend via an alternative method where you are, only to have them tell you that they have noise at that particular frequency. You go back and forth a couple of times, finally settle in on a mutually convenient frequency and have a contact whilst keeping note of the signal strength shown on your receiver. On a good day that will take a few minutes, on a bad day that might take much longer or not work at all. If you want to do this across multip

Foundations of Amateur Radio Mark Twain is often misquoted in relation to reports about his death, pithy as always, he said: "The report of my death was an exaggeration." Similarly the death of amateur radio has been reported on many different occasions. Letting amateurs near a Morse key, banning spark-gap transmitters, introducing transistors, integrated circuits, computers, the internet, software defined radio, the list grows as technology evolves. I can imagine our descendants decrying the death of amateur radio with the commodification of quantum computing at some point in the future of humanity. Yesterday I had an entertaining and instructional play date with a fellow amateur. We discussed countless aspects of our hobby, things like how you'd go about direction finding if you had access to multiple radios and antennas, what characteristics that might have, what you'd need in the way of mathematics, how you'd write software to solve the problem and how you'd go about calibrating such a system. Could yo

Foundations of Amateur Radio One of the many vexing issues associated with getting on-air and making noise is actually making that happen. So, let's look at a completely restricted environment. An apartment building, seven stories off the ground, no ability to make holes, an unsympathetic council, restrictive local home owners association, et cetera, et cetera. On the face of it your amateur radio hobby is doomed from the start. In reality, it's only just beginning. So, to hear HF right now, today, you can go online and listen to a plethora of web-based software defined radios. There's the canonical WebSDR in Twente and a whole host of others using the same or similar software. There's KiwiSDR, AirSpy, Global Tuners, and many more. This will give you countless radios to play with, coverage across the globe, the ability to compare signals from different receivers at the same time on the same frequency, the ability to decode digital modes, find propagation, learn about how contests are done, the sky's th

Foundations of Amateur Radio Over the past nine and a half years I've been hosting a weekly radio net for new and returning amateurs. Called F-troop, it runs every Saturday morning at 0:00 UTC for an hour. Feel free to join in. The website is at http://ftroop.vk6flab.com. In making the better part of six thousand contacts during that time I've learnt a few things about how nets work and how there are built-in assumptions about how a contact is made. There are several things that seem universally accepted that are not actually supported by the evidence and repeating them to new amateurs is unhelpful. For example, there is an assumption that on 2m there is signal reciprocity. By that I mean, what you hear is what the other party hears. On HF, contrary to popular belief, this is also not universally true due to massive power and antenna differences and signal reports on FT8 bear that out - for example, my signal is often reported at least 9 dB weaker than the other station. The reason that on 2m this isn't t

Foundations of Amateur Radio The other day I was adding an item to my to-do list. The purpose of this list is to keep track of the things in my life that I'm interested in investigating or need to do or get to finish a project. My to-do list is like those of most of my fellow travellers, unending, unrelenting and never completed. As I tick off a completed item, three more get added and the list grows. Given some spare time and to be honest, who has that, I am just as likely to find an item on my to-do list that was put there yesterday as an item that was put there 10 years ago. Seriously, as I migrate from platform to platform, my to-do list comes with me and it still has items on it that haven't been done in a decade, let alone describe what project it was for. Of course I could just delete items older than x, but deciding what x should be is a challenge that I'm not yet willing to attack. Anyway, I was adding an item to the list when I remembered seeing something interesting on the shed wall of a fellow

Foundations of Amateur Radio When one WSPR receiver just isn't enough The other day during a radio play date, highly recommended activity, getting together with friends, playing radio, seeing what you can learn, we were set-up in a park to do some testing. The idea was an extension on something that I've spoken about previously, using WSPR, Weak Signal Propagation Reporter, to test the capabilities of your station. If you're not familiar with WSPR, it's a tool that uses your radio to receive digital signals from WSPR beacons across the radio spectrum. Your station receives a signal, decodes it and then reports what it heard to a central database. The same software can also be used to turn your station into a beacon, but in our case all we wanted was to receive. If you leave the software running for a while you can hear stations across many bands all over the globe. You'll be able to learn what signal levels you can hear, in which direction and determine if there are any directions or bands that you can re

Foundations of Amateur Radio Radio amateurs like to do new things, celebrate, remember, bring attention to, and overall have fun, any excuse to get on air. One of the things that we as a community do is setup our radios in weird and wonderful places, on boats, near light-houses, on top of mountains, in parks, you name it. Another thing we do is create special callsigns to mark an occasion, any occasion. For example, to mark the first time the then Western Australian Chief Scientist, Professor Lyn Beazley was on air she used the callsign VI6PROF. When Wally VK6YS (SK) went on the air to educate the public about Rotary's End Polio Now campaign, he used VI6POLIO. More recently the Australian Rotarians of Amateur Radio operated VK65PFA, Polio Free Africa. When it's active, you'll find VA3FIRE to remind you of Fire Prevention Week in Canada, the Chinese Radio Amateurs Club operates B0CRA through to B9CRA which you can contact during the first week of May each year as part of the Chinese 5.5 Ham Festival. We c

Foundations of Amateur Radio The idea of building a crystal radio occurred to me a little while ago. I committed to building one, supplies permitting, before the end of the year. I can report that I now have a crystal radio. It works, as-in, I can hear a local AM broadcast station, and it took a grand total of three components costing a whopping two and a half bucks. Before I get into it, this isn't glorious AM stereo, or even glorious AM mono, this is scratchy, discernible, unfiltered, temperamental radio, but I built it myself, from scratch and it worked first time. Before I start describing what I did and how, I'm letting you know in advance that I'm not going to tell you which specific components to buy, since your electronics store is not likely to have the same components which would make it hard for you to figure out what would be a solid alternative if you didn't understand the how and why of it all. So, disclaimer out of the way, my aim was to build a crystal radio using off the shelf components

Foundations of Amateur Radio I'm looking at components. Not looking for, looking at. I have them sitting on the bench in front of me. A collection of six variable capacitors and six inductors. There's also a germanium diode, a breadboard, some connecting wires and two connectors. I don't quite need that many capacitors or inductors and truth be told a breadboard is overkill, but I found myself getting into the spirit of things and for the tiny investment it seems like the thing to get whilst you're dipping your toe into the art of electronic circuit prototyping. I am noticing something odd whilst I'm looking at these components, a familiar feeling in some ways, butterflies in my stomach. It's the exact same feeling as when I sit at the radio, getting ready to speak into the microphone just as I am starting a weekly radio net, something that I've now done about 480 times, not to mention the times when I did around 1600 interviews or broadcast live to the world, butterflies. I'm mentioning this because in m

Foundations of Amateur Radio Antenna testing in the field. If you've been around amateur radio for any time at all, you'll know that we spend an awful lot of time talking about antennas. How they work, where to get them, how to build them, how strong they are, how cheap they are, how effective, how resonant, you name it, we have a discussion about it. It might not be immediately obvious why this is the case. An antenna is an antenna, right? Well ... no. Just like the infinite variety of cars on the road, the unending choice of mobile phones, ways to cook an egg and clothes to wear to avoid getting wet, antennas are designed and built for a specific purpose. I've talked at length about these variations, but in summary we can alter the dimensions to alter characteristics like frequency responsiveness, gain, weight, cost and a myriad of other parameters. If we take a step back and look at two antennas, let's say a vertical and a horizontal dipole, we immediately see that the antennas are physically differe

Foundations of Amateur Radio Recently I made a commitment to building a crystal radio. That started a fevered discussion with several people who provided many helpful suggestions. This is the first time I'm building a crystal radio and to make things interesting I'm selecting my own components, and circuit diagram. What could possibly go wrong? Crystal radios have been around for a while. Around 1894 Indian physicist Jagadish Chandra Bose was the first to use a crystal as a radio wave detector, using galena detectors to receive microwaves. He patented this in 1901. The advice I was given sometimes feels like it harks back to 1894, with suggestions of using cats whiskers, razor blades, and any number of other techniques that create the various components to make a so-called simple crystal radio. At the other end of the scale there were suggestions to go to the local electronics store and buy a kit. The first suggestions, rebuilding historic radios from parts made of unobtanium would mean many hours of yak

Foundations of Amateur Radio One of the more fundamental aspects of long distance radio communication is the impact of the ionosphere. Depending on how excited the Sun is, what time of day it is and what frequency you're using at the time will determine if the signal you're trying to hear from the other side of the planet makes it to you or is on its way to a radio amateur on Proxima B who is likely to hear this podcast in just over 4 years from now. In other words, the ionosphere can act like a mirror to radio waves, or it can be all but invisible. As luck would have it, this changes all the time. Much like waiting for the local weather bureau for the forecast for tomorrow's field-day, there are several services that provide ionospheric predictions. The Australian Space Weather Service, SWS, is one of those. You might have previously known it as the Ionospheric Prediction Service, but Space is much more buzz-word compliant, so SWS is the go. If you're not a radio amateur, space weather can impact stuff h