Episodios

  • How does your member society represent itself?
    May 17 2025
    Foundations of Amateur Radio Around the world are thousands of associations, groups of people, clubs if you like, that represent radio amateurs. Some of those associations are anointed with a special status, that of "member society" or "peak body", which allows them to represent their country with their own governments and on the international stage to the ITU, the International Telecommunications Union, through a global organisation, the IARU, the International Amateur Radio Union. Some of these are known across our whole community, the ARRL in the USA, the RSGB in the UK, and the WIA in Australia. Some much less so, the CRAC, the Chinese Radio Amateurs Club, or the ARSI, the Amateur Radio Society of India, for example. In an attempt to get a deeper understanding of what distinguishes these organisations, I visited a dozen member society websites. Cultural sensibilities and aesthetics aside, the variety and sense of priority is both pleasing and astounding. Starting close to home, the WIA, the Wireless Institute of Australia, shows news as the most important and the top story is a radio contact between the International Space Station and a school, held about two weeks ago. The ERAU, the Estonian Radio Amateurs Association, features an article about the 2025 General Meeting outlining who was there, what was discussed and thanking the participants for their contributions. When I visited, the ARRL, the American Radio Relay League, top news item, was the renewed defence of the 902-928 MHz Amateur Radio Band, from a few days ago. The most important issue for the ARRL is that you read the latest edition of QST magazine, but only if you're a member. The RSGB, the Radio Society of Great Britain, has an odd landing page that links to the main site, which features much of the same content. The latest news is "Mental Health Awareness Week" and encourages us to celebrate kindness in our community. The DARC, the German Amateur Radio Club, has a page full of announcements and the top one was an article about current solar activity including a coronal hole and various solar flares. The ERASD, the Egyptian Radio Amateurs Society for Development, uses qsl.net as its main website. It features many images with text, presumably in Arabic, that unfortunately I was not able to translate. Curiously the landing page features some English text that welcomes all interested to join. I confess that I love the juxtaposition between a Yaesu FT-2000 transceiver and the images of Tutankhamun and the pyramids. The RAC, the Radio Amateurs of Canada, use their homepage to promote its purpose, and features many pictures of their bi-monthly magazine, which you can only read if you're a member, which is where many of the homepage links seem to go. The RCA, the Radio Club of Argentina, is promoting the 2024-2025 Railway Marathon, including links to descriptions of what constitutes a Railway Activation, how to reserve your station, and upcoming and past activations. There's also a reminder to renew your license. The ARSI, the Amateur Radio Society of India, has a very sparse landing page showing their mission and not much else. Clicking around gives you lots of information about the history, activities, awards and the like. Unfortunately, I wasn't able to find out how to become licensed in India. There's hardly any images. In contrast, the URA, the Union of Radio Amateurs of Andorra, lands you on a page with contact details and not much else. Clicking through the site gives you lots of pictures of happy people and maps, lots of maps. The KARL, the Korean Amateur Radio League, features an announcement with a link to the 24th Amateur Radio Direction Finding, from a week ago, but it requires a login to actually read it. The JARL, the Japan Amateur Radio League, features an announcement to a form you can complete to join the "List of stations from which you do not wish to receive QSL cards." The NZART, the New Zealand Association of Radio Transmitters, features a big button to latest news and clicking on it shows the "Jock White Field Day", which was held several months ago. I wasn't able to see the CRAC, the Chinese Radio Amateurs Club, since the page didn't load for me. The "Wayback machine", also known as archive.org, from a capture a few days ago, showed a news item announcing the intent to organise the 1st Class C Amateur Radio Technical "something", I say "something" because I cannot actually load the article and see what it has to say. The event was scheduled for a month ago, the announcement was from several months ago. Content aside, finding sites was interesting too, mind you, there's plenty of member associations that don't have any web presence at all. Is that by choice, or necessity? The IARU list of member societies conflicts with the list of national organisations shown on Wikipedia. The IARU has about 160 entries, I say about, since the list isn't really formatted as much as it's congealed. Let's just say, ...
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    8 m
  • A brief introduction to the HamSCI community
    May 10 2025
    Foundations of Amateur Radio

    Since becoming a licensed amateur in 2010, I have spent a good amount of time putting together my thoughts on a weekly basis about the hobby and the community surrounding amateur radio. As you might know, my interest is eclectic, some might say random, but by enlarge, I go where the unicorns appear.

    Over a year ago I mentioned in passing a community called HamSCI. The label on the box is "Ham Radio Science Citizen Investigation", which gives you a sense of what this is all about. It was started by amateur radio scientists who study upper atmospheric and space physics.

    More formally, the HamSCI mission is the "Continuation and extension of the amateur's proven ability to contribute to the advancement of the radio art."

    If you visit the hamsci.org website, and you should, you'll discover dozens of universities and around 1,300 people, many of whom are licensed radio amateurs, who are asking questions and discovering answers that matter to more than just our amateur community.

    For the eighth time the HamSCI community held an annual "workshop", really, an opportunity to get together and share ideas, in person and across the internet, a conference by any other name.

    Under the banner theme of "HamSCI's Big Year", over two days, 56 people representing 27 different organisations across 61 sessions, tutorials, discussions, tours, posters and demonstrations, explored topics all over our hobby, from the Personal Space Weather Network, capable of making ground based measurements of the space environment, to the Whistler Catcher Pi, a project to record the VLF spectrum to 48 kHz using a Raspberry Pi.

    You'll find research into HF antennas for the DASI or Distributed Array of Small Instruments project and associated NSF grants, exploring measurements of HF and VLF, combined with GPS and magnetometer across 20 to 30 stations.

    There's discussions on how to explore Geospace Data, such as information coming from the Personal Space Weather Station network, or PSWS, using the OpenSpace project and dealing with the challenges of visualising across a wide scale, all the way up to the entire known universe. Did I mention that there's work underway to add PSWS compatible receivers to Antarctica?

    There reports on observations and modelling of the ionospheric effects of the April 2024 solar eclipse QSO party, including Doppler radio, HF time differences, and Medium Wave signal enhancements, not to mention planning and promoting future meteor scatter QSO parties.

    There's, post-sunset sporadic-F propagation, large scale travelling ionospheric disturbances, GPS disciplined beacons, the physical nature of sporadic-E propagation and plenty more.

    As you might have heard me say at one time or another, the difference between fiddling and science is writing it down. It means that you'll find every session has accompanying documentation, charts, graphics and scientific papers. Remember, there's eight years of reading to catch up with, or learn from, or play with. The publications and presentations section on the hamsci.org website currently has 526 different entries.

    You might not be interested in the impact of radio wave and GPS scintillation, or rapid fluctuation in strength, caused during the G5 geomagnetic storm that occurred on the 10th of May 2024, or a statistical study of ion temperature anistropy using AMISR, or Advanced Modular Incoherent Scatter Radar data .. or you might.

    In case you're curious, "anistropy" is the property of being directionally dependent, in other words, it matters in which direction you measure, which might have some relevance to you if you consider that we think of the ionosphere and radio paths being reciprocal. If it reminds you of isotropy, that's because they're opposites.

    The point being, that amateur radio is a great many things to different people. If you're a scientist, budding, graduate or tenured, there's a home for you within this amazing hobby.

    I'm Onno VK6FLAB

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    5 m
  • Can we figure out how much the Sun really affects propagation?
    May 3 2025
    Foundations of Amateur Radio Recently I saw a social media post featuring a screenshot of some random website with pretty charts and indicators describing "current HF propagation". Aside from lacking a date, it helpfully included notations like "Solar Storm Imminent" and "Band Closed". It made me wonder, not for the first time, what the reliability of this type of notification is. Does it actually indicate what you might expect when you get on air to make noise, is it globally relevant, is the data valid or real-time? You get the idea. How do you determine the relationship between this pretty display and reality? Immediately the WSPR or Weak Signal Propagation Reporter database came to mind. It's a massive collection of signal reports capturing time, band, station and other parameters, one of which is the Signal To Noise ratio or SNR. If the number of sun spots, or a geomagnetic index change affected propagation, can we see an effect on the SNR? Although there's close on a million records per day, I'll note in advance that my current approach of taking a daily average across all reports on a specific band, completely ignores the number of reports, the types and direction of antennas, the distance between stations, transmitter power, local noise or any number of other variables. Using the online "wspr.live" database, looking only at 2024, I linked the daily recorded WSPR SNR average per band to the Sun Spot Numbers and Geomagnetic Index and immediately ran into problems. For starters the daily Sun Spot Number or SSN, from the Royal Observatory in Belgium does not appear to be complete. I'm not yet sure why. For example, there's only 288 days of SSN data in 2024. Does this mean that the observers were on holiday on the other 78 days, or was the SSN zero? Curiously there's 60 days where there's more than one recording and as a bonus, on New Years Eve 2024, there's three recordings, all with the same time stamp, midnight, with 181, 194 and 194 sun spots, so I took the daily average. Also, I ignored the timezone, since that's not apparent. Similarly the Geomagnetic Index data from the Helmholtz Centre for Geosciences in Potsdam, Germany has several weird artefacts around 1970's data, but fortunately not within 2024 that I saw. The data is collected every three hours, so I averaged that, too. After excluding days where the SSN was missing, I ran into the next issue, my database query was too big, understandable, since there are many reports in this database, 2 billion, give or take, for 2024 alone. Normally I'd be running this type of query on my own hardware, but you might know that I lost my main research computer last year, well, I didn't lose it as such, I can see it from where I am right now, but it won't power up. Money aside, I've been working on it, but being unceremoniously moved from Intel to ARM is not something I'd recommend. I created a script that extracted the data, one day at a time, with 30 seconds between each query. Three hours later I had preliminary numbers. The result was 6,239 records across 116 bands, which of course should immediately spark interest, since we don't really have that many bands. I sorted the output by the number of reports per band and discovered that the maximum number of days per band was 276. This in turn should surprise you, since there's 365 days in a year, well technically a smidge more, but for now, 365 is fine, not to mention that 2024 was a leap-year. So, what happened to the other 90 days? We know that 78 are missing because the SSN wasn't in the database but the other 12 days? I'm going to ignore that too. I removed all the bands that had less than 276 reports per day, leaving 17 bands, including the well known 13 MHz band, the what, yeah, there's a few others like that. I removed the obvious weird band, but what's the 430 MHz band, when the 70cm band in WSPR is defined as 432 MHz? I manually created 15 charts plotting dates against SNR, SSN, Kp and ap indices. Remember, this is a daily average of each of these, just to get a handle on what I'm looking at. Immediately several things become apparent. There are plenty of bands where the relationship between the average SNR and the other influences appear to be negligible. We can see the average SNR move up and down across the year, following the seasons - which raises a specific question. If the SNR is averaged across the whole planet from all WSPR stations, why are we seeing seasonal variation, given that while it's Winter here in VK, it's Summer on the other side of the equator? If you compare the maximum average SNR of a band against the minimum average SNR of the same band, you can get a sense of how much the sun spots and geomagnetic index influences the planet as a whole on that band. The band with the least amount of variation is the 30m band. Said differently, with all the changes going on around propagation, the 30m band appears to be the most stable, followed by the 12m and 15m ...
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    7 m
  • Being an amateur without either radio or antenna
    Apr 26 2025
    Foundations of Amateur Radio

    A recent comment by a fellow amateur sparked a train of thought that made me wonder why there is a pervasive idea within our community that you need a radio transmitter and antenna to be a radio amateur, moreover that for some reason, if you don't have either, you're not a real amateur.

    I suppose it's related to the often repeated trope that the internet enabled modes like Allstar Link, Echolink and even IRLP, are not real radio, despite evidence to the contrary.

    Instead of fighting this weird notion, I figured I'd get on with it and find a way to play even if you don't currently have the ability to erect an antenna or key a transmitter for whatever reason.

    Before I dig in, a WebSDR is a Software Defined Radio connected to the Internet. It allows a user to open a web browser, pick from a massive collection of receivers around the world and listen in. Some of these also have the ability to transmit, but more on that later.

    Here's the idea.

    Have you ever considered tuning to a WebSDR, using it to pick a signal and using your computer to decode that signal? I'm aware that some sites provide a range of in-built decoders, but that doesn't cover the wide spectrum of modes that amateur radio represents, let alone the modes that are not specific to our hobby.

    As I've said previously, many of the modes in use today are essentially the width of an audio stream. This means that if you tune a WebSDR to a frequency the audio comes out of your computer speakers. If that's voice, your job is done and you can hear what's going on. If it's something else, then you're going to have to find a way to decode this to get the message.

    So, if you send the audio from your web browser into something like Fldigi or WSJT-X, you'll be able to decode the signal if it's supported by those tools. This is true for all the other tools too, Morse, RTTY, you name it.

    Depending on which operating system you're using the way to implement this will differ. Starting with a search for "WebSDR and WSJT-X" will get you on your way. You might ask why I'm advocating WSJT-X, even though it only supports a small set of modes and that's a fair question. In my experience, it's the simplest to get running and get results. Two tips, make sure you set your configuration to indicate that you don't have a radio, otherwise it's going to attempt to control something that isn't there, and make sure that your computer clock is set accurately using NTP or Network Time Protocol. You can thank me later.

    Now I hinted earlier at transmitting. There's a growing range of places where your amateur license will give you access to a station somewhere on the internet and with that the ability to get on air and make noise. An increasing number of radio amateur clubs are building remote stations for their members to enjoy. There are also individuals and small groups doing the same independently. A few organisations are offering this as a service to paid subscribers.

    These tools often implement a remote desktop session where you connect to a computer that in turn is connected to a radio. The supported modes depend on what is installed at the other end. Others implement a slightly different method where you run specialised software locally, sometimes inside a web browser, that connects to a server across the internet, allowing you to run whatever digital mode you want on your own computer.

    I'll point out that even if you start with receiving digital modes using a WebSDR, you can expand that into transmitting at a later stage.

    So, no antenna, no transmitter, no problem, still an amateur!

    I'm Onno VK6FLAB

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    4 m
  • Becoming Mode Agile
    Apr 19 2025
    Foundations of Amateur Radio

    Over the years I've talked about different ways of using our license to transmit. I've discussed things like modes such as voice AM, FM, and SSB, and digital modes like FT8, WSPR, RTTY, FreeDV, Hellschreiber, Olivia and even Morse code.

    Recently it occurred to me that there is something odd about how we do this as a community. Now that I've realised this it's hard to unsee. Let me see if I can get you to the same place of wonder.

    Why is it that we as amateurs only use one such mode at a time?

    Let me say that again. With all the modes we have available to us, why do we only use one mode at a time, why do we get our brain into the mindset of one activity, stop doing that in order to move to another mode?

    It's weird. Amateur radio is what's called "frequency agile". What I mean by that is we are not restricted to a fixed number of channels like most, if not all other radio users. We can set our transmission frequency to whatever we want, within the restrictions imposed by our license conditions, and start making noise. There's agreement on what mode you can use where, but within that comes a great deal of flexibility.

    We have the ability to find each other. Call CQ and if the band is open and your station is transmitting a signal, the chance is good that someone somewhere on planet Earth will respond.

    We change frequency at will, almost without thought, but why don't we do this with modes?

    The closest I've seen is local VHF and UHF contests where you get different points depending on which mode you're using, and even that seems hard fought.

    It's weird. We have an increasing range of Software Defined Radios, or SDR, where your voice, or incoming text, can be transformed to a different mode at the touch of a button, but we rarely if ever actually use this ability.

    In case you're thinking that the restriction relates to the availability of SDR in the average amateur radio shack, most amateur modes fit within a normal audio stream and that same flexibility could be applied to the vast majority of transmitters scattered around the globe, but to my knowledge, it isn't.

    Why is that?

    Better still, what can we do about it? Can we develop procedures and processes to make us more, let's call it "mode agile", giving us the ability to change mode at the same ease as we change frequency?

    What would a "mode and frequency agile" amateur look like? What processes would you use? Right now the best we have is to QSY, or announce that we're changing frequency, but I've never heard anyone use that to describe a change of mode. Of course it's possible that I've led a sheltered life and not been on-air enough, but if that's the case, I'd love to hear about it.

    So, what is stopping us from becoming even more flexible? Do we need to practice this, develop better tools, teach new amateurs, have multimode nets, invent new modes that share information across different modes simultaneously, build radios that can transmit on different frequencies, or something else?

    I'm Onno VK6FLAB

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    3 m
  • Playing Games On-Air
    Apr 12 2025
    Foundations of Amateur Radio

    One of the basic aspects of being human and growing up is the process of learning. From a young age we explore our environment, play with others, have fun, fall over and bruise our knees, get up and try again. The playing aspect of this is often discussed as a way to keep things interesting. We add a competition element as an added incentive, so much so that we formaulate it into global competitions and call it sport.

    As a species it might surprise you that we spend about 1% of all Gross Domestic Product on sport, compared to science, which is about 2% of Global GDP. To give you some context, Agriculture accounts for about 4%, Manufacturing is 15%, Industry is about 26%, and Services account for roughly 62%. If you noticed that this is more than 100%, take it up with the World Bank, I'm a radio amateur, not an economist.

    Over the years I've explored different aspects of our chosen hobby of amateur radio. Time and again I return to experimentation, learning and having fun. Now I absolutely concede that my idea of fun and yours might not match, my GDP side quest is likely evidence of this, but in my opinion, this embodies the range of how we as a disparate community interact and exchange ideas across the ionosphere and closer to home using what we all can agree on is pretty close to magic.

    So, what is my point? Fair question. Having fun and learning.

    If you've ever had the opportunity to listen to aviation radio, and I'd encourage you to, the YouTube channel, VASAviation is a great place to start, comes with maps, explanations and subtitles. You'll discover that the complex domain of aviation communication is a dynamic environment where miscommunication matters and often has severe consequences. It's not all incidents and accidents though. If you look for Air Traffic Control legend "Kennedy Steve", you'll come across some of the funniest exchanges captured on ATC frequencies, all the while staying professional.

    So, how does this relate to amateur radio and you?

    Well, at the moment we have a few types of exchanges where we can practice our skills. The most obvious one is a thing we call contesting. A scored and rule bound activity where you're expected to exchange information and are declared the winner in a category. It's a little like sport and some have attempted to rephrase amateur radio contesting into a field that they're calling "radio sport". I have mixed feelings about this because there isn't much in the way of spectator activity associated with this.

    Another exchange is calling for DX contacts, sharing an exchange across distance, attempting to contact as many countries as possible, with the prize being membership into the fabled DXCC, the Century Club that acknowledges your prowess in making contact with a hundred countries.

    The most common exchange is the net or discussion group. It can be formal, like the weekly F-troop I've been hosting since 2011, or it can be ad hoc, one amateur chatting to another, sparking spontaneous discussion among several stations on frequency.

    We also do things like radio direction finding, someone sets up a transmitter and everyone playing tries to find the source as quickly as possible. First one to find it wins.

    It made me wonder if there are other things we might come up with.

    Has anyone played chess across HF? Or if you want to involve a larger group, what about playing Bingo! or a game of trivia? Anyone considered an MMORPG, or Massively Multiplayer Online Role Playing Game?

    The point being that we can play games, have fun, and learn in an environment where there are many factors affecting your ability to communicate, so we can all get better at keying the microphone and getting the message to the intended recipient.

    While we're having fun, nobody said that this needs to be a voice activity. An FT8 session could well be coerced into transmitting chess moves and nobody said that you have to do FT8 on the same frequency that WSJT-X is using.

    So, what games can you come up with and learn from?

    I'm Onno VK6FLAB

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    5 m
  • What is Amateur Radio really about?
    Apr 5 2025
    Foundations of Amateur Radio

    When you join the community of radio amateurs, or when you briefly look over the shoulder of the nearest devotee, you're likely to discover that this is a hobby about a great many different ideas. Over the years I've discussed this aspect of our community repeatedly, talked about the rewards it brings you, about the camaraderie, about communication, learning, research, soldering, disaster recovery, public service, and all the other thousands of activities that this hobby represents to the world.

    While all those things might be true for some, they're not true for everyone. Many amateurs get excited about antennas, some immediately, some eventually. The same can be said for all the other points of what we think of when we discuss our hobby with others.

    Recently I saw a random comment on social media from a person who was having issues with their mobile phone on their property. I considered and ventured an opinion about what might be the cause and how they might go about discovering what was going on.

    I debated about how I signed off. It's a recurring dialogue, should I reveal upfront that I'm a radio amateur, or should I leave that to be discovered at a later date? In my experience, the wider society has a, let's call it a rocky relationship with our hobby. With the decrease in profile and numbers comes an increase in misconception about who it is that we are, and what it is that we do.

    At some level, there's an understanding that at some point this was an activity that grandpa might have engaged in, or it might be someone preparing for the end of the world, seeing our community as the way forward when all else fails, not at all helped by that slogan being used by a vocal amateur radio body, the ARRL.

    Given that, as I saw it, the issue was related to radio interference or a weak signal, I signed off, for better or worse, "Source: I'm a licensed radio amateur", and crossed my fingers.

    This started a discussion about the issue, which revealed that the person was having other problems with other communication tools in their remote village. I don't want to go into the specifics, because it's not about what their issue is, where they live and what other resources they might have access to, or not. It's about us, radio amateurs, because of course it is.

    Aside from the cringe associated with my sign-off, if you have suggestions on how to improve it, I'm all ears, I had a take-away that I thought was worth discussing. As I'm beginning to suspect, it's about the fundamental nature of our hobby, what it is and what it does.

    Troubleshooting.

    Let me say that again. Amateur Radio is fundamentally about "troubleshooting", in other words, systematically finding and fixing complex problems.

    So, let's explore this.

    If you consider we're all about communication in difficult environments, I'd point out that getting that message across is an exercise in troubleshooting.

    If you lean towards learning, then consider deciding what to study and why, more troubleshooting.

    If you suggest it's about soldering, what happens when you poke the leg of a component into the wrong hole? Do I really need to say it?

    Every time you think you've nailed down the intangible nature of our hobby, you can point at troubleshooting. Don't get me wrong, it's about having fun too, but you and I both know that fun is balanced by frustration, again, you guessed it, troubleshooting.

    In our increasingly technical, interconnected and complex world, the ancient pursuit of amateur radio is teaching you an invaluable skill, over and over again, all but inevitably: "The art of troubleshooting".

    So, next time you are asked why we should be doing this thing, why we are obsessed with this hobby, why we spend many hours, dollars and effort, it's all about finding out why something doesn't work as expected and funnily enough, the more you do it, the better you get.

    For radio amateurs, troubleshooting is our superpower.

    I'm Onno VK6FLAB

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    5 m
  • What is the difference between a Dummy Load and an Antenna?
    Mar 29 2025
    Foundations of Amateur Radio Recently I started an experiment I plan to run for a year. Using a WSPR beacon and a dummy load I'm transmitting 200 mW, 24 hours a day across all bands supported by my hardware, in this case it covers 80m, 40m, 30m, 20m, 17m, 15m, 12m, and 10m. The aim of the experiment is to determine if, and to what extent my dummy load can be heard outside my shack. Why? Because I've not seen anyone do this and because a dummy load is widely believed to not radiate, despite evidence to the contrary. Together with the transmission side, I've also configured an RTL-SDR dongle, initially with the telescopic antenna it came with, now, since my HF antenna isn't being used by the beacon, I'm using it instead. It's about five metres away from the beacon, outside. It's a helically wound whip resonant on the 40m band built by Walter VK6BCP (SK). It's what I've been using as my main antenna for the past seven years or so. While I'm telling you this, my beacon has been heard by my dongle 1,182 times across all eight bands. Some of those reports were from inside the shack, some from outside, some while I was monitoring a single band, and for the past week or so, I've been monitoring all the bands supported by "rtlsdr_wsprd", 18 in all. Purposefully, this includes some bands that I'm not transmitting on, because who knows what kinds of harmonics I might discover? The receiver changes band every half hour, so over time when I monitor a band will shift across the day, this is deliberate. I don't know when a stray transmission might suddenly appear and this will give me the best chance of hearing it, short of using 18 different receivers. At this time, my beacon hasn't been heard by any other station. I'm not expecting it to, but that's why I'm doing this experiment in the first place. I'm not in any way reaching any sense of "DX on a dummy load", but it got me thinking. My beacon can be heard, albeit by me, from five meters away. So it's radiating to some extent. I've already discussed that this might come from the patch lead between the beacon and the dummy load, or it could be the dummy load itself, or some other aspect of the testing configuration. Regardless of the situation, there is a signal coming from my beacon that's wirelessly being heard by a receiver. That's the same as what you'd hope to achieve with any antenna. So, in what way are an antenna and a dummy load different, and in what way are they the same? Whenever someone asks this, the stock answer is that an antenna radiates and a dummy load doesn't. My experiment, 20 days in, has already proven that this distinction is incomplete, if not outright wrong. Even so, if we take it on face value, and we say, for argument's sake, that a dummy load doesn't radiate and an antenna does, then how do we materially distinguish between the two? How does an antenna compare to a dipole, Yagi or vertical antenna and where does the isotropic radiator fit in this? The best I've come up with so far is a spectrum line comparing the various elements. Let's say that at one end of the spectrum is a dummy load, at the other is an isotropic radiator, to refresh your memory, that's the ideal radiator, it radiates all RF energy in all directions equally. Somewhere between the two ends is a dipole. We might argue if the dipole sits equally between a dummy load and an isotropic radiator, but where does a Yagi or a vertical fit in relation to the dipole? Also, if you turn a Yagi in the other direction, does it change place? So, perfect this notion is not, but here's my question. What's the measurement along the axis between the dummy load and the isotropic radiator? It's not SWR, since the ideal antenna and a dummy load share the same SWR, unless this line is a circle that I don't know about. It might be Total Radiated Power expressed in Watts, but that seems counter intuitive. It would mean that in order to determine the effectiveness of an antenna we'd need to set-up in an anechoic chamber, basically a warehouse sized room where incoming radiation is shielded to some predetermined standard. Do we measure gain using a VNA and call it a day, or is there something else going on? Remember, we're attempting to quantify the difference between a dummy load and an antenna. In case you're wondering, I'm asking the question. In the 15 years I've been part of this community, I've never seen any coherent response. The Internet seems to return a variation on the radiation vs. not-radiation pattern, but so far I've not seen anyone quantify this, or perhaps I haven't understood it while it was staring me in the face. I even checked the syllabus for the three license classes in Australia. The single reference that the regulator appears to specify is that at the introductory level you are required to, wait for it, recall that when testing a transmitter, a non-radiating load, or dummy load, is commonly used to prevent a signal from being radiated. Very ...
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    6 m
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