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Foundations of Amateur Radio

Foundations of Amateur Radio

By: Onno (VK6FLAB)
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Starting in the wonderful hobby of Amateur or HAM Radio can be daunting and challenging but can be very rewarding. Every week I look at a different aspect of the hobby, how you might fit in and get the very best from the 1000 hobbies that Amateur Radio represents. Note that this podcast started in 2011 as "What use is an F-call?".℗ & © 2015 - 2026 Onno Benschop Physics Science
Episodes
  • Building a shack: Part 6 - Noise

    Building a shack: Part 6 - Noise
    Jan 17 2026
    Foundations of Amateur Radio Noise la la la la la hinders if I were a rich man effective a noise annoys an oyster communication but a noisy noise annoys an oyster more. Or said differently, when you're trying to communicate, something that the hobby of amateur radio does in spades, you'll need to deal with a phenomenon called noise. This noise comes in different forms, but the effect is the erection of barriers to successful communication. We refer to the impact of noise as a signal to noise ratio or SNR, the signal being the desired information, the noise the undesired interference. Expressed in decibels so you can deal with a massive range using a small number, an SNR greater than 0 dB means that the signal is stronger than the noise. Building a shack requires that you consider noise in many forms. If you've been a radio amateur for a few moments, your mind is likely to head straight for the hiss, crackle and pop you might hear whilst attempting to communicate on HF, but there's a few other things to discuss. There's all sorts of electronic noise received by your radio. In addition, there's audio noise picked up by your ears, and often your microphone. Then there's the noise that you produce, either from your transmitter into the rest of the building, or from your mouth or speakers into the ears of the people you share the space with. Starting with audio, having a space that you can close the door on is a good way to limit the noise coming into and leaving your shack. An alternative is to wear headphones and generate text to speech, or prerecord your voice, ready for a contact, potentially ideal for contesting, not so much for free form discussion. Another consideration is audio from other radios, including those tuned to a local broadcaster, or aviation frequencies. In other words, if you're transmitting with a microphone, make sure that there's no other audio coming through. In some cases it's even illegal to transmit that audio, but in all cases it's noise that makes communication more difficult. This kind of audio noise mitigation is pretty straightforward. In stark contrast, achieving the same with electronic noise is pretty much a balancing act between budget and effectiveness. The impact of noise is inversely proportional to distance. Essentially, the closer it is, the more impact it has. With that in mind, when you start dealing with noise, start nearby and work your way out. As you eliminate the nearby noise, other sources will become apparent. Without turning this into a noise mitigation class, the process is essentially one of elimination. First locate the noise source, then eliminate it. That's easier said than done. For example, if the noise source is a power supply sitting on your bench, you can turn it off, except if that power supply is the one powering your radio, so perhaps I should say: "attempt to eliminate it" instead. There's plenty of ways to have a go at this and volumetric kilotons of content published on the subject, some of it even useful. In many, but not all cases, noise is an electrical phenomenon that enters via any means possible and you'll need to attempt noise mitigation at multiple points of entry. Obvious sources are the power supply, coax and the antenna connection, the speaker cable, the microphone lead, and if you're using a computer, the USB, serial or Ethernet cable and within the computer itself. Each requiring different approaches. The obvious one is to disable the noise, that is, turn off the offending device. As I said, that might not be an option, but you can replace noisy gear, or place it further away. There's isolation, using tools like ferrites and chokes to stop the noise from reaching your radio. Often in the form of a clip-on blob, you'll find these on things like monitor and USB cables. Place the ferrite as close as possible to the input of your radio. If it's loose on the cable, wind it through the ferrite, the tighter the better. There's software solutions with varying levels of effectiveness. You'll find DSP or Digital Signal Processing knobs and buttons on many radios. They're generally helpful for narrowband repeating noises, like the hum of an electric motor or power supply. There's tools that attempt to impose a noise on your signal that cancels out the noise, anti-noise, if you like, by receiving the noise, inverting it and adding it to your signal, thus, at least theoretically, eliminating it, noise minus noise is silence. This can take the form of a device for noise coming in from the antenna, but it also applies to things like noise cancelling speakers. In audio this is called active noise cancelling. There's also a new crop of noise cancelling software, using A.I. or Assumed Intelligence, that captures your signal, attempts to figure out what's noise and what's not, removes the noise and then feeds it back to you. Your Mileage May Vary and if you break it, you get to keep both parts. Consider your privacy and security...
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    8 mins
  • Building a shack: Part 5 - Antenna Shenanigans

    Building a shack: Part 5 - Antenna Shenanigans
    Jan 10 2026
    Foundations of Amateur Radio Putting your station together is best described as a juggling act, since you'll discover that everything depends on everything else and the more you plan, the more you learn and the more variables become apparent, none more so than with the selection of an antenna. Antennas are endlessly variable. To give you a taste, imagine a loop of wire, shaped like a circle. As you stretch the circle, it becomes an oval, if you pull on four corners, it's a square, pull it tight between two points and it more or less becomes a single wire. In other words, one piece of wire can essentially make an infinite number of antennas, and we haven't even varied the material, length, thickness or coating. So, to discuss antennas is to embark on a lifelong journey of exploration and me telling you to get one over another is not going to help, instead I'd like to discuss some considerations that you might not have encountered. The obvious issue of space is generally the first consideration. Then there's the neighbours and their sense of aesthetics, or lack thereof. There's local laws to abide by and sometimes permissions and permit requirements, though in many cases it seems that seeking forgiveness is a quicker route to success. Your Mileage May Vary. Talk to your local amateur club. There's the property owner to consider. If that's you, great, drill away, if not, you will need to tailor your antenna selection to the amount of renovations required. If you live in a restricted location where there are all manner of rules about the things that you cannot do, you might need to think carefully about your options. Stealthy antennas are a thing. As I've said previously, inside your roof might be an option, but there are others. Some examples to consider. If there's a TV aerial on your roof, will that look similar to a 70cm Yagi, or could it hide a 2m vertical? Do you have a metal gutter which might act as an antenna, or could you use Christmas light clips to hang a wire antenna from your gutters? Could you hide a vertical in a plastic down-pipe? Could you dangle a ladder-line antenna out a window at night, or use thin wire to hold up your plants while hiding your antenna in the garden, or can you use a beverage antenna that's lying on the ground, or hidden under the fence capping? Could you tune up your fence for that matter? In other ways to make your hobby look invisible in plain sight, could you use an antenna that looks like a roof vent, or if you're into moon bounce, could you repurpose a satellite dish? Could you make your outdoor washing line into an antenna or add a flagpole vertical antenna that also happens to soothe your vexillology sensibilities? While we're talking stealth, you can paint your antenna to match the decor. To get your antenna up in the air, could you use a length of wood, a pool cleaning or painters pole, strapped to your pergola, gazebo, balcony railing, or some other existing structure? Can you use the edging of a shade sail, professionally installed, it comes complete with mounting points. It doesn't stop there, I've heard of several amateurs who managed to park a sailboat, with the mast up, in their driveway without ever once floating it in a nearby body of water. Of course this is not exhaustive, nor is it meant to be, it's really a trigger to think about some options you might not have discovered. In other words, if you need stealth, you can be creative, rather than buy an antenna off the shelf. Speaking of buying off the shelf, there's nothing quite like buying a wonderful antenna, the answer to all your questions, only to discover that it needs tuning and tweaking, to the point where you might spend a year getting familiar with all its quirks. That's not to discourage you from picking that path, just to warn you that there is no such thing as the perfect antenna. If you are less space restricted, building a tower or a mast, the difference being that a tower stands all by itself, like the one in Paris, a mast needs guy-wires to keep it up. You'll likely need to consider failure, engineering standards and concrete, not to mention maintenance. So, how do you go about selecting the perfect antenna to suit your needs? In the same way that a magician pulls a rabbit from a hat. In other words, there's a trick. It's pretty simple, start small. With that I mean, start with a simple wire antenna. It will achieve a number of things that only experience will give you. For starters, it will prove that your shack works. As-in, end-to-end. That might not sound like a big deal, but there are many different moving parts in building a successful shack, making your first contact is going to be a milestone worth logging, more on that another day. While making your first contact is momentous, getting an antenna in the air will also allow you to hear what your neighbourhood sounds like. Is it completely RF quiet, in which case, where do you live and do you have a spare ...
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    6 mins
  • Building a shack: Part 4 - coaxial cable alternatives

    Building a shack: Part 4 - coaxial cable alternatives
    Jan 3 2026
    Foundations of Amateur Radio When you start the process of getting your hobby off the ground, either for the first time, or after a hiatus, you might be left with the impression that the only way to "do amateur radio" is to have a shack, a place where you can set-up your gear, and connected to that gear using coax, one or more antennas. While that's a common scenario, it's not the only one at your disposal. We are after all in the game of communication and over the past few decades options have exploded. Starting closest to the traditional radio, coax and antenna, is to consider indoor antennas. There's many to choose from. You can install one in the same room as your shack, or, you can build your antennas in the roof space, either way, invisible from the outside can sometimes be a requirement. Stealth is a topic all its own, and no doubt we'll get to that another time. A word of caution. If you do have an indoor antenna and associated coax, consider your transmitter power levels, since it's likely that given the close proximity, you'll exceed emissions safety standards, or you'll cause harm to other electronic equipment in the building. QRP or low power is a good way to go if this is something you're considering. If we step away from a traditional radio, coax, antenna configuration, you can build your shack in other ways too. For example, you can use a local repeater which you might trigger from a local handheld radio. Often dismissed as being for local communications only, there are thousands of repeaters across the globe offering a variety of bands, frequencies and modes. Often you can access a local repeater that can be connected to a remote one using a bewildering array of technologies, some using the internet, some using traditional RF. You'll find repeaters on 10m, 6m, 2m, 70cm and 23cm. There's nothing stopping you making your own repeater. You don't even need to go through the effort of making it completely standalone, for example, my Yaesu FT-857d has a detachable face-plate or head, connected to the main body by a short cable. There are plenty of other radios with a similar configuration. Presumably designed for the installation in a vehicle, where the head needs to be near the driver and there's unlikely to be space for the body, you can run a longer cable from the head to the body and install it somewhere more convenient. In my case it was bolted underneath the removable floor into the boot next to the spare tyre. There's several solutions that replace the connecting cable with an internet connection. Now, that internet connection can be across the room, from inside your shack to your garage, or between your shack and a remote hill where you have permission to put up a bit of gear. In fact, the same type of setup can be used to connect to shared radios, and companies like Elecraft, Flex Radio and ICOM make specific remote heads that can operate remote radio equipment, marketed as RF decks, without needing to install and maintain computers at either end, but more often than not, this equipment is brand or model specific. Which raises another option. You can connect to remote equipment across the internet using your computer, which means that your shack might be a computer, a laptop, or a mobile phone and your gear might be in a different country. Many radio clubs have discovered that their often extensive radio shack is virtually unused during the week, and have installed remote equipment to allow you as a member to connect, sometimes as part of your membership, sometimes with an extra fee, since there are costs associated with setting this up and keeping it running. At some point you're going to discuss this with other amateurs and you're potentially going to hear someone tell you that this is not "real radio". Considering over a century of radio evolution, from spark-gap through valves, transistors, integrated circuits and software defined radio, where exactly is the "real radio" line drawn? Is using WSPR, RTTY, FT8, Hellschreiber, Olivia, SSTV, PSK31, Domino, MFSK and thousands of other digital modes "real radio"? If the answer to that is an emphatic "yes", then ask yourself, how do you actually use those modes? The answer looks suspiciously like a computer running digital mode software, either connected to a physical radio in the same room, or connected to one across the internet. In other words, with the proliferation of communication alternatives, amateur radio is evolving. No doubt it will evolve further. So, today, a perfectly viable, and some might say, modern, amateur radio shack might not actually have any traditional RF based radio gear, though perhaps a hand-held might be something to consider when you next treat yourself, not because without it you're not a real amateur, but because it opens your world to other means of communication, something which I think is perhaps even more important than building the perfect shack. In other words, you are not required ...
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    6 mins
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