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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?".
Updated: 4 hours 22 min ago

The inherent redundancy of a compromise antenna

Sat, 10/16/2021 - 12:00
Foundations of Amateur Radio

For an activity that's seeped in the art of communication, amateur radio is a diverse collection of people, joined by a common interest and kept together using imperfect language describing an intrinsically complex science in the hope that we can learn from each other to get on air and make noise.

In this cooperative endeavour, language is important.

Let me start with a limerick by Arthur Frackenpohl:

There was a young fellow of Perth Who was born on the day of his birth He married, they say On his wife's wedding day And died when he quitted the earth

Stay with me.

In this day and age, first and foremost, let me give you a short summary, cobbled together from bits and pieces of a new invention, conceived whilst watching the evening sunset in close proximity to the beach.

What this cornucopia of tautologies has to do with our hobby might not be obvious, but let me illustrate.

Consider the phrase: "a compromise antenna", as-in, "Oh, I'd never use that antenna, it's a compromise antenna."

If you've been in this community for any time at all, you'll have heard that phrase and unless someone pointed it out, you might not have realised that it's essentially unhelpful.


Because as I've said many times before, all antennas are a compromise, by definition. This is true at several levels.

At a fundamental level, an isotropic antenna is a theoretical antenna that radiates equally in all directions - horizontally and vertically with the same intensity. It's infinitely small and operates on all frequencies with infinite bandwidth. It should be obvious, but this antenna cannot physically exist, so every built antenna represents a collection of trade-offs or compromises and no antenna can radiate more total power than an isotropic antenna.

Beyond that, within the physical constraints of antenna building there are many more compromises. Now this might not be immediately obvious, so let me elaborate.

Consider a 28 MHz, seven element Yagi antenna. With a 12m boom, a 5.3m reflector element, a turning circle of 7.5m and weighing in at 53 kilo. At 20m above the ground it has a gain of 17.5 dBi and handles 1.5 kW. It's physically capable of withstanding 180 km/h winds. It's a lovely piece of kit and if you have the space, it's absolutely something you might want to receive for your birthday and bolt to a mast somewhere near your radio.

If all antennas are a compromise, you might ask yourself, how is this beautiful 10m Yagi a compromise?

For starters, its total radiated power is less than an isotropic antenna. It works between 28 and 29 MHz, but nowhere else. It radiates signals really well in one direction, but not in any other. It requires lots of open space and as a fixed installation, it must be on a heavy duty rotator clamped to a tall mast. To actually acquire and install requires more funds than I've spent on all my radios to date.

Some of what I've mentioned might be acceptable to you, some not. For example, if you're always portable, this antenna makes no sense. You make choices to select an antenna that's best suited to the job and in doing so, you are introducing compromises.

Additionally, there are amateurs who would have you believe that a compromise antenna is one with high loss.

High loss in comparison to what?

If you live in an apartment block, there's no way that you can fit that 10m Yagi inside your bedroom, so you compromise and use a magnetic loop antenna instead. If you're on the top of a mountain, there's no opportunity to erect a structure, so you use a self-supporting vertical. If you're in a car, you cannot erect a horizontal dipole and drive down the highway, so you bolt a whip to your jalopy.

All of the choices you make to fit a purpose, an environment, a budget and available material will combine into an antenna that hopefully gets you on air making noise.

When someone tells you that an antenna is a compromise antenna, what they're really saying is that you made compromises that they're unwilling to make. That's easy to say if you have infinite space, money, experience and opportunity. In other words, they're just blowing hot air.

The whole point of antenna building is to find a particular set of compromises that suits your situation at the time that you're doing it. The intent of this hobby is to learn what the impact of a particular choice is and how it affects the operation of an antenna in a specific situation.

Next time you hear the redundant phrase "that's a compromise antenna", ask what compromises they are describing that they don't accept and decide for yourself if they are compatible with what you're attempting to achieve within the resources available to you.

I'm Onno VK6FLAB

Standard Information Exchange in Amateur Radio

Sat, 10/09/2021 - 12:00
Foundations of Amateur Radio

The art of storing information in such a way that it doesn't devolve into random gibberish is an ongoing battle in the evolution of the human race. Egyptians five thousand years ago were perfectly happy storing information using hieroglyphs. They used it for well over three thousand years, but today you'd be hard pressed bumping into anyone on the street who knows one, let alone one thousand characters.

Latin fared a little better. It's been in use for over two thousand years, but other than fields like biology, medicine and of course some religions, the best you can hope for is et cetera, mea culpa and my favourite, carpe noctum, that and a few mottos scattered about.

Using technology to store information is no better. If you have a 3.5 inch floppy disc tucked away in a drawer, can you still read it today and do you know why it's called a floppy disc? What about a 5.25 inch, or 8 inch floppy. What about tape. Do you still have backups stored on DAT?

Even if you could physically read the information, could you still make sense of it? Can you open a VisiCalc spreadsheet file today? That was invented during my lifetime, first released in 1979. The latest release was in 1983.

My point being that storing and retrieving information is hard.

Amateur Radio is an activity that has been around since the early 1900's, over a century of information. We describe our collective wisdom in books, magazines, audio recordings, websites, podcasts, videos and tweets.

One of the more consistent sources of information coming from our activity is logging, specifically QSO or contact logging. There are bookshelves full of paper log files, but since the advent of home computing, logging now is primarily an electronic affair.

If you've upgraded the software on your computer, you know the pains associated with maintaining your log across those transitions. If you've changed operating systems, the problem only got worse.

Currently there are primarily two standards associated with logging, the ADIF and Cabrillo specifications. Both are published ways of describing how to store information in such a way that various bits of software can read the information and arrive at the same interpretation.

As you might expect, things change over time and any standard needs to be able to adopt changes as they occur. How that happens is less than transparent and in an open community like amateur radio, that's a problem.

Used primarily for logging contacts, the Amateur Data Interchange Format or ADIF is published on a website, adif.org. There's lively discussion in a mailing list and since its inception in 1996, it's evolved through many versions, incorporating change as it happens. Like the adoption of new digital modes, new country codes and administrative subdivisions.

Used for contest logging, Cabrillo is published on the World Wide Radio Operators Foundation, or WWROF web site which assumed administration for the specification in 2014. It documents changes as they occurred, like adding contest names, station types and contest overlays. While there's clearly activity happening, there doesn't appear to be a public forum where this is discussed.

Speaking of public.

The DXCC, or DX Century Club is a radio award for working countries on a list. ADIF stores those country codes using the DXCC country code number, which is part of the specification published by the ARRL, the American Radio Relay League. The list of DXCC entities is copyrighted by the ARRL, which is fair enough, but you have to actually buy it from the ARRL to get a copy. This is a problem because it means that any future archivist, you included, needs access to a specific version of both the ADIF and the then valid DXCC list, just to read the information in a log file. To put it mildly, in my opinion, that's bonkers.

Relying on external information isn't limited to ADIF. Cabrillo relies on external data for the format of the Location field which indicates where the station was operating from. Among others, it refers to the RSGB, the Radio Society of Great Britain who maintains a list of IOTA, or Islands on the Air, published on a web site that no longer exists.

There are other issues.

It appears that for the Cabrillo specification there is no incremental version number associated with any changes. Version 3 of Cabrillo was released in 2006. There are 31 changes published to update Version 3, but as far as I can tell, they're all called Version 3, so anyone attempting to read a Version 3 log will not actually know what they're dealing with. To give you a specific example of three changes. In 2016 the 119G band name was changed to 123G, which was changed in 2021 to 122G. All three labels refer to the same band, but until you actually start looking at the file will you have any indication about the version used to generate the file.

Let's move on.

Contesting. Not the logging or the on-air activity, but how to score a contest. What activity gets points and what incurs a penalty? Do you get different points for different bands, for different station prefixes, for low power, for multiple operators, for being portable and plenty more. Can you make contact with the same station more than once, if so, how often and under which circumstances? What is the exchange, how does it change, if at all? Each of these choices are weighed by contest managers all over the globe and they do it every time they run their contest. For some contests that means that there are dozens of rule versions across the years. To give you some idea of scale, the modern CQWW was first run in 1948 and there's at least one amateur contest every weekend.

Now imagine that you're writing contest logging software that keeps track of your score and alerts you if the contact you're about to make is valid or not, or if it incurs a penalty if you were to log it. That software is driven by the rules that govern a particular contest.

Some contest software is updated by the author every time a major contest is held to incorporate the latest changes. Other contest tools use external definition files, which specify how a particular contest is scored.

As you might suspect, that too is information and it too is in flux and to make matters worse, there is no standard. So far, the tools that I've found that make any concerted attempt at this all use different file formats to specify how a contest is scored and of those, one explicitly points out that their file format doesn't incorporate all of the possible variation, leaving it to updating the software itself in order to incorporate changes that aren't covered by their own file format. That is sub-optimal to say the least.

Personally, I think that there is a place for a global standards body for amateur radio, one that coordinates all these efforts, one that has a lively discussion, one that uses modern tools to publish its specifications and one that does this using public information with an eye on record keeping.

I'm Onno VK6FLAB

You in the community ...

Sat, 10/02/2021 - 12:00
Foundations of Amateur Radio

The other day a member of our community proudly showed off their plaque for first place as a Short Wave Listener or SWL in the Poland SP DX Contest. Together with their dad they listened on 80m using a WebSDR and logged all the contacts they were able to hear. Their participation didn't include transmitters, since neither have got their callsigns, yet.

To me this illustrates exactly what it's like to dip your toes into the world of amateur radio and it's a path that many amateurs have taken to become licensed and transmitting.

I'm mentioning this because that same short wave listener also won a platinum diploma from the anniversary of Stanislaw Lem's 100th birthday amateur contest.

If that name sends tingles of excitement down your spine, you're familiar with his work. If not, you might be interested to know that Stanislaw Lem was a world acclaimed Polish writer of science fiction who died in 2006.

This random discovery, in addition to giving me ideas about opportunities for contests and awards, reminded me of other times when in one setting I've been surprised by information relating to another setting. In this case, science fiction. In previous workplaces I've come across software developers, technicians and managers who outside their roles in computing were active as volunteer fire-fighters, paramedics, writers, stage performers, singers, foster parents and more.

It occurred to me that we in the amateur radio community spend most, if not all, of our time discussing amateur radio, but that we likely share other interests with our community. I recently discovered other science fiction nerds, a cos-player, there's some volunteer fire-fighters and the like, no doubt there's more.

My point being that in addition to finding more common ground between us as a community, we also have the opportunity to share our hobby with other people who share our interests. It's hard to imagine that science fiction fans and fire-fighters for example are unable to relate to amateur radio.

Don't get me wrong. I'm not advocating that you hit the members of your other communities over the back of the head with amateur radio. Instead, think of it as another way to connect to that group.

The thing that strikes me about our amateur community is the diversity that it encompasses. It means that there's likely plenty of other interests that you will find that bind you to other amateurs and it likely means that your other hobbies and interests might share some of your amateur interests.

Truth be told, as all consuming as amateur radio is, it's not the only thing that defines you and it's not the only thing of interest to the people around you.

What those interests are is up to you.

Only one way to find out.

Talk with your friends.

I'm Onno VK6FLAB

The sun shines on our hobby in unexpected ways.

Sat, 09/25/2021 - 12:00
Foundations of Amateur Radio

When you begin your amateur radio journey, one of the first things you learn about that's not directly involved with radios and antennas is the ionosphere and its impact on long distance communications. Immediately after that you are more likely that not to be introduced to the biggest plasma experiment in our backyard, the Sun.

With that introduction comes information about solar flares, solar flux, sunspots, geomagnetic storms, coronal mass ejections as well as the solar cycle, the solar index and associated propagation forecasts.

Before I dig further, I will point out that I'm mentioning this with the ultimate aim for you to get on air and make noise, so fasten your seat-belt and let's go for a ride.

The Sun is big. If it was hollow, it could fit more than a million Earths inside. The Sun accounts for 99.8% of the total mass of our entire solar system. About 73% of the Sun's mass is hydrogen, about 25% is helium and the rest, about 1.69% is made up of all the other heavier elements, both gasses and metals, which add up to around 5628 times the mass of Earth.

The Sun rotates. Counter-clockwise. Since it's mostly plasma, it doesn't rotate like Earth does. The equator takes about 24 days, the poles around 35 days and because its rotating on an angle of about 7.25 degrees from Earth's rotation axis, we get to see more of the solar north pole in September and more of the solar south pole in March.

Earth orbits the Sun in a year, but it's not a circular orbit. We're closest to the Sun in December and furthest from the Sun in June. It takes about eight minutes and 19 seconds for a photon leaving the Sun to reach Earth, but that same photon can take between 40,000 and 170,000 years to travel from the core where two atoms were heated and compressed to fuse into a new element releasing a photon and heat. It takes this long because the photon keeps bumping into other atoms along the way. While we're at it, consuming about 4 million tons of hydrogen per second, the Sun will take another 5 billion years to consume all the available hydrogen.

Whilst we experience the Sun as a source of light on a daily basis, as a radio amateur you know that light is just one tiny part of the electromagnetic spectrum. It should come as no surprise that the Sun is radiating across all frequencies all the time, only some of which is visible to our naked eye.

As an aside, it's interesting to note that our eyes are essentially translating light into electricity, or said differently, your eye converts radio spectrum into electricity, something which your radio antenna also does.

Back to the Sun.

I'm highlighting this level of solar complexity because there's so much talk about the A index, the K index, the SFI, the solar cycle and propagation by experts and amateurs that it's easy to hide behind those numbers and think that a low A between 1 and 6, a low K of 0 or 1 with an SFI above 100 will give you the propagation you're looking for.

If you think for a moment that the weather forecaster has a difficult job accurately telling you if you need to postpone your outdoor activation because of rain or snow, then you can begin to understand just how complex the interplay between the Sun and our ionosphere is. And I haven't even mentioned that the ionosphere isn't static either.

It's important to remember that the cute little weather icons you see on the TV news are just as much an indicator of expected weather as the A, K and SFI numbers are for the Sun and its impact on radio propagation. They give you an idea of what might happen, but it doesn't mean that on any given day something completely random and isolated happens that just affects your station and the path that a radio signal took from your antenna to that other rare DX station.

Just like it would be smart to take an umbrella with you when there's rain forecast, it's also smart to consider the bands you want to operate next time you go on air with a particular solar forecast, but just because it might rain, doesn't mean you're guaranteed to get wet.

So, in other words, wait for it, get on air and make some noise!

I'm Onno VK6FLAB

We need more glue in our hobby ...

Sat, 09/18/2021 - 12:00
Foundations of Amateur Radio

Since December 2010 I've been licensed as a radio amateur. For some this seems like a long time ago, for others, it's just the beginning. In my time thus far I've attempted to document and describe my journey and in doing so, I've had the unbeatable pleasure of hearing stories from others who were inspired by my efforts to join, or rejoin the hobby.

It occurred to me that it's hard to tell when you look at any one amateur if the ink on their licence is still wet, or if the whole certificate is faded and yellowed with time.

You also cannot tell by looking if one amateur turns on their gear in the car during the daily commute, or if they go out on expeditions to remote locations twice a year.

The callsign a person holds tells you even less, let alone the class of their license.

In our community we talk about mentoring and we call such people Elmers, but do we really use this as a way to glue together our hobby as its namesake might suggest?

As a result of my profile, there's a steady stream of commentary about what I do and how I do it. As you might expect, there's both good and bad, sometimes describing the same thing from opposite sides in equally heated terms.

I'd like to take this opportunity to point out that playing the man and not the ball will get you completely ignored. If however you have a specific grievance with any technical aspect of what I'm contributing, by all means let me know, but be prepared to provide references because it might come as a surprise, I do research before I open my mouth. That's not to say that I don't make mistakes, I'm sure I do and have.

Before this turns into a self congratulatory oration, I'd like to point out that all the negative feedback I see all around me does nothing to grow our hobby, does nothing to encourage learning, does nothing to reward trial and error and it doesn't contribute to society at large in any way.

I'm mentioning this because I also receive emails from amateurs who have left the community, not because of lack of interest, but because of the bullying that they've experienced.

I know that there are several local activities that I avoid because it's just not fun to bump into people who are friendly to your face whilst being vicious online.

It continues to amaze me that this topic keeps recurring and that it keeps needing to be called out. One thing I can tell you is that ignoring it doesn't work. I've described previously what you should do instead when you're the subject of such petulant behaviour, but it bears repeating. Say it out loud.

"Thank you for your comment. I don't believe that it's in the spirit of amateur radio. Please stop."

Feel free to use that phrase anytime someone in this hobby makes you feel uncomfortable.

One final observation. If you've not personally experienced this behaviour that's great, but it doesn't mean that it doesn't happen or that it's not endemic. Consider for a moment how you'd feel if you were attacked whilst being active in a hobby you love, for no other reason than that the person attacking you didn't like the wire you were using to construct a dipole or some other equally outrageous reason like your gender, sexual orientation, license class, choice of radio or preferred on-air activity.

Say it with me:

"Thank you for your comment. I don't believe that it's in the spirit of amateur radio. Please stop."

I'm Onno VK6FLAB

The Fox Mike Hotel Portable Operations Challenge

Sat, 09/11/2021 - 12:00
Foundations of Amateur Radio

Getting on air and making noise is what it's all about, so last week, that's exactly what we did. Randall VK6WR, Jishnu VK6JN and I participated in the Fox Mike Hotel Portable Operations Challenge which is specifically scored to deal with power and mode differences between stations by using a handicap system that they liken to playing golf. Having been the winner of the Sir Donald Bradman Award in the Millmerran Memorial Golf Tournament for making the highest score on the day, this speaks to me in more ways than I can say. In case you're wondering, more hits in golf is bad and I'm not a golfer.

Scoring in the Portable Ops Challenge is based around four different attributes, the power you're using, the nature of your station, portable or fixed, the mode used and the number of transmitters in use.

To achieve this, you exchange a maidenhead grid square, a combination of letters and numbers that indicates your location on earth, which is then used to determine how many kilometres per Watt are used to make the contact.

If you're portable, you get a multiplier benefit in the scoring.

Depending on the perceived difficulty of the contact, you score more points. In this case, SSB is harder than CW, which in turn is harder than a digital mode.

Finally, the more transmitters you have, the less each contact is worth. Two transmitters, means you score half the points for each.

With that in mind, a QRP portable station with a single transmitter calling CQ on SSB is the best way to make points and that is something that I'm always up for.

In our adventure, we opted for a slight change, instead using FT4 and FT8, using 40 Watts, portable, on the side of a hill in a local park and during the four hours we were active, we managed six contacts, one over SSB, the rest using digital modes and we all had several goes at getting the best out of our station.

Our set-up consisted of a small folding table next to my car with a computer, a radio and a thermos flask with hot tea to ward off the chill in the air. Power was supplied by an 80 AH battery. The radio was an Icom IC-7300 that Randall brought along.

The antenna we used was a Terlin Outbacker, multi-tap whip that was attached to my car with a 12m counterpoise run along the gutter.

None of us had ever seen such excellent conditions with such a low noise floor in the middle of the city. We were enjoying the last warm sun of the day from Kings Park in Perth, Western Australia. It's a 990 acre park, larger than Central Park in New York, set aside for public use in 1831 and gazetted as a public park in 1872. The park is open 24 hours a day and features a botanic garden with thousands of species of Western Australia's native flora and fauna, overlooks the central business district, the Swan River and the Darling Ranges and best of all, there's no radio noise. It did get chilly towards the end, but I'm pretty sure we all went home with all our fingers and toes intact.

Jishnu also brought along his FT-817 and a tiny multi-tap telescopic whip that we strapped to a nearby steel rubbish bin and using that set-up was able to detect and transmit WSPR signals across the globe as part of experimentation with his station.

One of the unexpected benefits of not yelling CQ into a microphone ad-nauseam was that we were able to continue our conversation, hearing stories from each other and enjoying hot pizza when dinnertime came around without needing to stuff food into the same place where CQ calls were intended to originate.

My car isn't quite ready to go completely portable, but this little outing again proved to me that portable vehicle based operation has a charm all its own and the Fox Mike Hotel Portable Operations Challenge is going to be on my dance card next time it comes around!

When was the last time you left your shack and went portable?

I'm Onno VK6FLAB

What's in a sound?

Sat, 09/04/2021 - 12:00
Foundations of Amateur Radio

Over the past few weeks I've been having my hearing tested. I've had the opportunity to discuss sound in some detail with an audiologist. Today as a result of a collision between a jar of chilli pickles and a tiled floor I've come to the realisation that sound is important in unexpected ways.

It will probably not come as a surprise to you that sound has an emotional component. Just think of a particular song, or a voice, or something that you've heard previously. The sound of a jack-hammer, or a bell, a horse or a jet, each completely different, impact on your mood. Some sounds are pleasant, others jarring. Some make you feel happy, others make you anxious or even angry.

For some time now I've observed in myself that there are times when I cannot stand sound and other times when I invite it into my life.

For example, if there's a HF radio going in the background and I'm attempting to have a conversation with a person in the shack, the sound coming from the radio causes irritation, to the point of needing to turn it off in order to actually hold a conversation. On the other hand, if there's a contest on, I can sit, happy as a clam, listening to HF all day and night, working out what station is calling, and making contact.

I'm raising this because it occurs to me that amateur radio is unlike broadcast radio where you're expected to actively monitor what is being transmitted. In my experience as a radio broadcaster you're talking into a microphone and the headphones you're wearing are connected to a radio receiver which is tuned to the station on which you're broadcasting. This gives you immediate live feedback on the state of your audio levels.

As an aside, I once witnessed a fellow broadcaster who didn't feel the need to wear headphones. They were blissfully unaware that their voice was being transmitted into silence because the audio fader on their microphone was down.

In amateur radio however, we don't often do such things. We transmit blind most if not all of the time. It's rare that we even hear our own voice on-air, let alone hear it in real time. If that's not enough, using sideband, it's easy to modify the sound of a person by changing the frequency slightly, making their voice either higher or lower, just by adjusting the dial.

It occurred to me that how your voice is perceived by the other station assists in how that station can hear you and make contact.

Using the local repeater is a good but subtle example. If you've listened for a while, you might have observed that there are stations that are easy to understand and others that are not. Sometimes that comes down to individual accents, but in my experience a much larger impact is caused by the actual transmission itself.

Is the microphone gain set correctly, is there any filtering in play, is the station on the correct frequency, is the transmitter using the correct mode and other more subtle things like background noise, speaking volume and distance and direction in relation to the microphone.

We often talk about less being more and you already know that I'm a big fan of low power or QRP operation. Making contacts is absolutely about using the right antenna, the right mode, the correct band and time of day, but the sound coming from your station is just as important.

If you have the ability to use two radios simultaneously, then I'd recommend that you find a way to either use a local repeater, or a cross-band repeater, or even a remote web-based radio, to hear what you actually sound like on-air, live, and experiment with the various settings on your radio in order to test and improve the quality of your voice.

Whilst we as radio amateurs don't standardise our signals, though personally I think it would be a great idea, there's plenty of improvement to be had by taking some time out of your next on-air activity to have a long hard listen to yourself.

I'm Onno VK6FLAB

Taking your shack mobile

Sat, 08/28/2021 - 12:00
Foundations of Amateur Radio

When I first started in this hobby I found myself surrounded by other amateurs who all seemed to have a spare room in their house, or a spare building near their house, or even a property somewhere, dedicated to amateur radio. There was an endless parade of equipment, antennas, tools, workshops, spare parts and the like. Frankly it was overwhelming.

A decade on, I have some perspective to share on that first exposure. For me the hobby was brand new. I didn't have a family history, there were no amateur friends I'd grown up with, no electronics uncle or anything even remotely resembling any of that. What I was exposed to wasn't a new thing, it represented something that had been going on for years, decades and lifetimes even.

It quickly became apparent that having a shack was desirable, but in my case, at the time, unobtainable, so instead I did the next best thing I could think of. I built a shack in my car. That was a journey that took several years to make. At the end of it, I removed my radio from the car and moved it onto a spare table in my office.

I have spent countless enjoyable and sometimes frustrating hours in my car shack and I learnt that it's almost always temporary. If you're not the exclusive user of the car, then your shack isn't always available and in that case it also needs to be family friendly, as-in, no cables, mounts, brackets and the like that can cause damage to a person, or the equipment. This limits the options you have.

At the end of my car journey, I had a spare battery in the back, the radio and tuner were mounted under the floor next to the spare tyre, there was an antenna mount attached to the car, there was braiding throughout the car, connecting all the body panels together and the remote control head was detachable from a suction mount that doubled as a mobile phone holder. Antennas, one for HF, one for VHF were stowed against the roof lining with a strap around the roof hand grab of the rear passenger. An external speaker was mounted below the head rest of the centre rear passenger.

What I learnt was that this setup was good for short stints, for mobile operation, for contests on the run and for working DX at lunch time at the beach. Trying to do digital modes, attempting to work a pile-up, or doing several other activities I love were not really feasible and as a result I decided to pull it all out.

At this point all that remains in the car are the braiding, the control lead, the speaker, the coax and the antenna mount. I plan to rebuild my car shack in the not too distant future. More on that in a moment.

I moved house and found myself in an office that was perfect for multiple reasons. It was separate from the rest of the living space, so I didn't need to put away stuff. It was big enough to house a dedicated radio table and it's got pretty simple access to the outside world for running coax. It gives me a dedicated place to do radio and have stuff set-up permanently.

I noticed one thing after having this available.

I didn't actually get on-air any more than when I was using my car shack. If anything it's less. I think it's because it's also my office and I already spend plenty of time doing office activities that playing radio isn't all that different. I'm going to keep my set-up, but I'm going to go back to my roots and add a radio back into my car.

It's still a family car, so I need to consider the other uses that it's put to, but I think I can make it work. I recently installed an 80 Amp Hour battery with an automatic charging circuit. It was put there to power the dash-cams, but it was scaled with amateur radio in mind.

I don't yet know which radio I'm going to put into the car, I really do like my FT-857d, but there are other options available to me, so I'm going to experiment.

One fundamental change I'm going to make is that the radio will be installed in such a way that it can be easily unplugged and removed. Not because I want to remove it from the car, but because I want to be able to go even lighter, take the radio onto the beach, or into a park or up a summit. I'll likely bolt the whole lot into a Pelican case and make it a mobile go-unit that happens to live in my car.

I don't think I'll add digital functionality at first, but I'm eyeing off the idea of dedicating an old mobile phone, which is essentially a computer, screen, battery and internet connection in one to the task, but I'll let you know how that goes.

What I do know, with hindsight, is that less is more.

I'm Onno VK6FLAB

What's in a unit?

Sat, 08/21/2021 - 12:00
Foundations of Amateur Radio

In our hobby we use kilohertz and megahertz enthusiastically. Sometimes even gigahertz. The other day during a discussion the question arose, what comes after tera, as in terahertz? I couldn't remember, so I had to look it up, peta comes next, then exa, zetta and yotta, derived from the Greek word for eight.

That in and of itself was interesting, but it turns out that Greek isn't the only language used in attributing SI metric prefixes, SI being the International System of Units. Of the 20 units, which I'll get to in a moment, there's 12 with Greek origins, five deriving from Latin, two from Danish and one from Spanish.

The units are used to describe how many of a thing there are in base-10, so, a thousand of something is kilo, or ten to the power of three, which gives us kilohertz. A gigahertz is ten to the power of nine and so-on. Interestingly, kilo is derived from the Greek word thousand, but mega comes from the Greek for great. Both hecto, as in hectopascals and deca as in decathlon originate in the Greek words for hundred and ten. The prefix pico, as in picofarad comes from the Spanish word peak and femto as in femtowatt comes from the Danish for fifteen, as in ten to the power of minus 15. Apparently a zeptomole of a substance contains 602 particles, even NASA says so, let me know if you can find a source for that.

I could devote my entire discussion on these 20 units, adding for example that their naming wasn't all done at the same time, the most recent additions are yotta and yocto, as I said, derived from the Greek for eight, being ten to the power of 24. How's that eight you ask? Well, three times eight is 24. I'm not saying it's intuitive, but there is logic.

In looking at all these units, and specifically the smaller ones, milli, micro, nano, pico and the like, it occurred to me, is there a way to go below one Hertz, could you have half a Hertz?

Hertz is the number of oscillations per second, a single Hertz being one per second. Half a Hertz would be one oscillation per two seconds. I started wondering what to look for in discovering if anyone has been playing with this. For the life of me, I couldn't think of what to search for and my experience tells me that if you cannot find the answer online, you're asking the wrong question.

This morning, with a fresh cup of coffee in my hands, it occurred to me that anyone doing this kind of stuff would be using SI units, so they'd be using decihertz, centihertz, millihertz, microhertz and nanohertz, perhaps even picohertz. So I went searching.

Turns out that this actually exists. After wading through endless results with conversion tools and dictionaries, there's plenty of research to find.

The unit decihertz is being used in gravitational wave interferometry, specifically, there's a Japanese, space-based gravitational wave observatory in the works with hopes of launching their three space craft if they can find funding.

It doesn't end there.

There are experimental imaging studies being made on malignant and benign human cancer cells and tissues looking at decihertz all the way down to yoctohertz, that's ten to the minus 24.

Inside Apple software development documentation, in addition to mega, giga and terahertz you can find links to milli, micro and nanohertz as predefined units.

NANOGrav stands for North American Nanohertz Observatory for Gravitational Waves and it uses the Galaxy to detect them. It was founded in 2007 and is part of a global community of scientists in places like Australia, where the Parkes Pulsar Timing Array is located - yes, that Parkes - made famous from the film "the Dish" and Europe with the European Pulsar Timing Array, combining five separate radio-telescopes, all coming together under the banner of the IPTA or International Pulsar Timing Array.

The point of my little exploration is that if you're curious about random things, you can often come across activities and ideas you know nothing about and learn something along the way.

Today I learnt that there is such a thing as a sub-Hertz signal, it's being explored all over the globe with scientists in different fields and it's happening without much in the way of public awareness.

What did you learn today and which SI prefix didn't I use?

I'm Onno VK6FLAB

Being an equipment custodian

Sat, 08/14/2021 - 12:00
Foundations of Amateur Radio

A couple of weeks ago an amateur put out a call on the local email discussion list. The message was simple, it read: "I have a 606A HP Signal Generator with a copy of the Operating and Service Manual. It covers 50 kHz to 65 MHz. Free to a good home :-)"

It's not the first time that such a message has done the rounds, but this time my reply was quick enough for it to be first. Overnight I became the new custodian of a Hewlett Packard 606A Signal Generator.

A signal generator is a tool that can form a specific carrier across a range of frequencies in much the same way that your amateur radio can. In this case, the HP-606A can cover all the amateur HF bands and everything in between. The signal that's generated is calibrated, that is, it's of a specific power level, very stable, clean and it can be used to calibrate other equipment.

To set the scene, the HP-606A was released into the wild in 1959. You might call it vintage at this point. It's the size of a modern microwave oven, so I'll need to set aside some bench space in order to actually use it. According to some it's "the best analogue signal generator ever built". It's been in production for decades, with plenty of information to be found online.

Unlike most modern gear, this equipment comes fully documented by the manufacturer, to the point of user manual revisions depending on the serial number and including essentials like circuit diagrams, parts list, spare parts list, calibration instructions and the equipment needed, how to open it up, tests to conduct after repair, how to conduct regular maintenance and how to replace the tubes in it.

Yes, I did say tubes, or valves, or glow in the dark electronics.

At this point I've not yet switched it on. You might wonder why that's the case. This unit has internal voltages exceeding 500 Volt DC, so some care is required. Inside are at least four electrolytic capacitors. Think of each of them as two pieces of aluminium sandwiched together, separated by a piece of foil and electrolytic paste, all rolled up into a cylinder.

When an electrolytic capacitor is built, the process to convert these components into an actual capacitor involves forming it, which means that the manufacturer applies a specific voltage to the pins of the capacitor and in doing so, causes a chemical reaction which makes all manner of funky stuff happen, including unidirectional conductance, something you're looking for in a capacitor.

Over time, when not in use, or in my case, in storage, this chemical reaction reverses and the capacitors are back to rolled up aluminium with some foil in between. Powering it up in this state will let the smoke out.

It turns out that in many cases you can apply the voltage again and reform the capacitor. Apparently, according to the author of Tu-Be Or Not Tu-Be Modification Manual by H.I. Eisenson, applying the voltage for five minutes plus one minute per month of storage does the trick. In my case, I can leave the capacitors in circuit and apply the voltage externally using a Variac, a Variable AC Transformer, loaned to me by Denis VK6AKR.

Doing the math is a little tricky, since we don't really know when the unit was last powered up, but we're told that it was some time in the last decade, so a couple of hours should suffice, but there are some wrinkles in relation to voltage and managing the step to powering up the tubes, so when I've made it happen, I'll let you know.

Denis was kind enough to help with opening up the cabinet and having a look-see inside. We noticed that it has previously been expertly repaired with a few replaced components and Denis managed to identify some likely failed tubes, so we're on the scrounge for those. Together we did some initial tests and ran up the unit using low voltage to determine if the various test points were actually showing the proportional voltages that were expected. This isn't like a digital circuit where it either works or not, using a Variac, you can slowly power this up, to a point, and test along the way.

This brings us to the provenance of this tool.

I got it from Dave VK6AI and from discussion, we think it came from the estate of Don VK6HK, now silent key. I've met Don's widow who happens to be the neighbour of a friend, so at some point when I have it working I might give her a call. I don't know who owned it before Don. I do know that when it was released, in 1959, it was sold for $1540 US Dollars, the equivalent of $14,000 in today's money, or half a car back then.

Based on serial numbers, this HP-606A appears to have been manufactured between October 1961 and August 1966, so it's older than I am. In case you have extra information, the serial number is 009-01180 and my email address is [email protected] If you have spare valves, a 12B4A is high on the list, get in touch.

While Denis and I were exploring inside the guts of this function generator, we were at the clubhouse of the local WA VHF Group, surrounded by other amateurs who were doing their own thing. At one point I looked up and noticed two amateurs in deep discussion about using a piece of software, CHIRP, to program a handheld radio on a Windows 10 laptop, whilst I was sitting across the table, picking through the guts of a 1960's piece of equipment. It made me smile, thinking about the history that those two extremes represented.

Becoming the custodian for such a significant piece of equipment isn't for everyone. I've been given suggestions to toss it out and buy something modern, but I have to confess, even though I'm software personified, SDR to the core, well, aiming to be, this piece of equipment does something for me.

What equipment do you own that makes you go all misty eyed?

I'm Onno VK6FLAB

All the things that aren't amateur radio...

Sat, 08/07/2021 - 12:00
Foundations of Amateur Radio

Recently I illustrated the diversity of our community by highlighting social media posts made to a single community over a 24 hour period. Each reflecting a different aspect of our community.

It occurred to me that although those things are amateur radio, some more obviously than others, there's a whole other side of the community that isn't amateur radio.

Look at radio astronomy for example. One of my friends is an astronomer and we've been having loads of fun learning from each other. I'm getting exposed to concepts like Fourier transforms, interferometry, sampling and plenty of the mathematical concepts that underlie my interest in amateur radio.

Then there's things like physics. While I've always been interested, long before I met my physics teacher in high-school who helped me kick off a career in computing, I've been playing with light bulbs, batteries, disassembling old hardware like the valve radio that I was given when I was about twelve or so.

There's the continued curiosity about audio. I've been making mix-tapes since I was nine, and that has blossomed into an ongoing interest in audio production, some of which is reflected in my weekly podcast and fuelled by my hearing loss.

My interests outside amateur radio have always been wide and varied. I've learnt to fly an aeroplane, learnt to navigate a sailboat, learnt to drive a truck, installed satellite dishes in the bush and built a mobile satellite ground station, built software solutions for piggeries and bakeries, provided logistics for remote outback events, built vehicle mounted GPS tracking and mapping solutions and I continue to read articles as they come my way.

What amateur radio has given me is a context, a framework if you like to bring together these wide ranging fields and make them hang together.

An obvious, though simple example, is learning the phonetic alphabet. In amateur radio it's a given that you'll need to learn that so you can effectively communicate using a poor signal path, but my phonetic learning predates my amateur radio exposure by at least a dozen years. In order to pass my aviation radio certificate, I was required to learn the phonetic alphabet before I was allowed to use the radio.

It's only a small example, but it's illustrative on how, for me at least, amateur radio is the glue that binds it all together.

It happens at other levels too. I've mentioned in the past that looking at a television antenna on the roof of any house before getting a license was a non-event. Today I can't look without thinking about propagation, how the antenna is aligned and if it's installed back-to-front or not. Once you know a thing, it's hard to un-see, or unlearn the background of it.

The same happens when I spot an antenna in the wild, stuck to a lamppost, or bolted to a random roadside cabinet. Previously they would go unremarked, today I wonder what information they're transmitting or receiving, what band they're operating on, who owns the equipment and what interference they might be causing or experiencing in their environment.

I have a growing interest in computer controlled manufacturing like 3D printing, laser engraving and CNC and spend some of the available time in the day learning about how that works, how to improve things and I wonder about how the speed of communications between the various components create an RF field of some sort and what that does to other components and circuits.

As a final experience, recently I had a medical procedure where there was a notice supplied with the logging hardware that specifically called out amateur radio as a source of electromagnetic radiation and that I was required to refrain during the process due to a potential failure of the equipment. If anything, for the first time in a long time, I felt that there was a visible link between my hobby and the rest of the community, since that notice was given to every single person, not just the radio amateurs.

Some links between amateur radio and the rest of the world are visible and some are not. What kinds of interactions between the hobby and society at large have you come across?

I'm Onno VK6FLAB

The diversity of our hobby is breathtaking.

Sat, 07/31/2021 - 12:00
Foundations of Amateur Radio

You've heard me say that amateur radio is a thousand hobbies in one. It's not my idea, but it speaks to me in ways that are hard to articulate. Today I found a way that might give you an inkling just how vast this community is.

One place where our community gathers is on-air, but it's not the only place. There are clubs, websites, email lists, video channels and other outlets all catering for different amateur radio users and their interests. One such place is the social media site Reddit. In the so-called amateurradio sub with currently over 88 thousand members, there is a lively community discussing many of the different aspects of our hobby.

Over the past 24 hours, 23 posts were made in that single community.

"Thanks, K-2722 hunters", was a photo about activating Carolina Beach State Park, as part of an activity called Parks on the Air, or POTA. To participate you can either go to a park, set-up your station and make contacts, or you can stay at home and listen out for people who are doing that.

"It's not high-high, it's hee-hee", a meme around the sound that the Morse Code generates when you send the letter H followed by the letter I, commonly considered laughter.

"Why don't scanners have FM radio?", a discussion around the perceived lack of FM mode on scanners.

"Help with TYT MD-380 CPS", a question from an amateur who purchased a new radio and is looking for software to program it.

"Portable on the Space Coast. QRP on a speaker wire antenna.", a video of an amateur making an activation in Florida and showing off their set-up.

"Could not hit DMR repeater", an amateur sharing that they figured out that they couldn't hit a repeater because they had their radio set to low power and wanted to share that with the community.

"Antenna advice part 2", asking about how to set-up antennas for dual use, how to amplify the signal, use rotators and what kind of coax to use.

"ISS SSTV Aug 6-7 145.800 MHz FM", linking to a news item announcing slow scan television coming from the International Space station in August.

"FT-3DR APRS message question", exploring the specifics on how Automatic Packet Reporting System or APRS messages are sent. Think of it as global distributed SMS via amateur radio.

"Is it okay to leave a handheld radio on while it's on its battery charger 24/7?", with answers to the question that's puzzling one owner of a radio.

"Extra test question", asking about how to learn for the test and wondering if the techniques needed are different when compared with obtaining the "tech" exam.

"Just got my first radio! Now to prep for the test, but first a question about saving time after I pass it...", asking about how to register before the test to speed things along.

And that's just over half way there.

"Maldol TMH-21 / TMH-71 handhelds - any info?", asking about a new to them radio from around 2007.

"2021 Berryville, VA (US) Hamfest - any reddit community members going?", looking for others going to the first hamfest in their region for a long time.

"CB Radio is Going FM! Why is the FCC Doing It?", linking to a video that discusses the changes on how CB radio is getting another mode.

"What is the 'right' way to learn morse?", the age-old question, one that I'm still am working through.

"Sidetone distorted on QCX mini? How do I fix this? It gets better or worse when I move the radio around, but the problem doesn't go away. Anyone else's QCX do this?", with a video showing the issue.

"Aluminium roof trim + HF dipole", with a question on what kind of effects might happen as a result of the combination of the two.

"Never owned a Radio be for please help lol. I got 2 of these on the way any tips for beginners? [sic]", excited new owner looking for advice.

"I finally got my qsl cards printed!", with pictures to show the artistic prowess involved.

"Legality of transmitting digital data over FM audio", asking about the specifics on how data may or may not be transmitted in the United States.

"It's no pie plate on a kayak, but you gotta work with what you have, right?", showing off a frying pan as a magnetic base. If it works, it's not silly at all.

"Very New Here", asking about how to explore radio waves.

Those 23 different posts are all about amateur radio, from one single community, on one day. Each post from someone finding their way in the community, discussing something that's important to them, sharing their experience and contributing to that community. Reddit alone has at least a dozen amateur related communities, covering electronics, specific radios, amateur software development and more.

The thing about this hobby is that it's different things to different people. For some it's about getting on air and making noise, for others it's learning about whatever comes their way. This hobby is so vast because it touches so many aspects of life, it innovates, leads and contributes in ways that are often invisible and that's why it's so engrossing.

What's your latest interest in this hobby and what keeps you coming back for more?

I'm Onno VK6FLAB

How are contests scored?

Sat, 07/24/2021 - 12:00
Foundations of Amateur Radio

The essential purpose of an amateur radio contest is to get on air and make noise. Each contest has a set of rules on how they intend to achieve this. An integral part of the rules is the idea that you establish a contact, a QSO, with another station and exchange some predefined information. Likely the callsign, a signal report and often something else, a serial number, the age of the operator, a maidenhead locator or the CQ or ITU zone. I'll race past the discussion around sending 5 and 9 as a standard signal report and move right along.

To validate your activity, you record this information in a log and after the contest has concluded, you share your log with the contest organiser who collates and processes the submitted logs to determine a winner. As a participant you look for your callsign on the results page and if you're lucky you get some form of trophy, a certificate, a plaque, or more often than not, a PDF. An amateur radio contest is not a particularly high stakes competition.

Recently I asked a group of contesters a question: "How do you learn why a QSO was excluded from your score?" I asked because one of the eight contacts I managed during a recent contest was disallowed, leaving me with an unexplained discrepancy between my log and the results. I will note that this entry didn't affect my ranking, I won my category, mainly because I was the only entrant - hah!

Depending on whom you ask, this is either a simple or a complex question.

The simple explanation states that if the contact isn't in the log of both stations it's not a valid contact. This interpretation was extremely popular in the group I asked.

It was not the only answer I received.

When I spoke with individual contesters they came up with different answers to my original question.

For example, if I log everything right, if I'm using a serial number, the number increments each time and my log shows that, then my log entry should be valid, even if the other station didn't log it correctly. Note that I said log, not copy, as-in, they repeated back what I gave them, but logged it incorrectly.

I also wondered what would happen if I was using a club-station callsign and accidentally called CQ with my own callsign and a station logged that callsign instead of the club-station. Should they be penalised because they logged what was actually exchanged?

There's more.

For example, what happens if the times are not identical? Based on the simple explanation, this would not be a valid contact, so you would not get recognition for this exchange and in some contests an invalid contact will produce a penalty to both stations.

Another variation to the simple answer occurs if the contest organiser doesn't receive a log for every station and as a result, some contests set a maximum number of contacts for stations without logs.

All this came within the context of attempting to discover how log validation happens, who decides what's valid and what rules are used. During my group conversation, two contest managers shared how they scored their particular contests and showed that they attempted to award the benefit of doubt to each station. One decided after the discussion to change their interpretation to the simple explanation I've already looked at.

I wanted to know if there was any standard and other than pointing vaguely in the direction of a few large contests, I didn't actually manage to find any definitive discussion on how this works, if it's universal, which I suspect it isn't, and if it changes over time, which I know it does.

The largest annual contest is the CQ World-Wide. In a 2012 blog post the contest committee discusses the time window of a contact and explains that they allow a 15 minute window, so as long as both contacts agree within 15 minutes, the QSO is allowed. That post also pointed out that if the time for one station was out by 45 minutes, none of their contacts would be allowed and anyone who made contact with that station would by implication get a penalty.

Clearly there are variations on how this is handled.

I asked if there is validation software for logs that checks this and if that software is open source so others can look at how decisions are made and see how these evolve over time. Is there an arbitration that goes beyond the standard phrasing in most contests: "The decision of the contest committee is final."

I was told that this wasn't necessary and I should focus on more practice. I beg to differ. I've been contesting for a decade now, I have plenty of winning certificates on my wall. I'd like to improve my skill and I'd like to learn why and how my contacts are disallowed and I'd like others to be able to do the same.

Log checking software is written by humans who interpret the rules and write software to conform to those rules. In order to see what rules are in place and to validate that, the source of that software must in my opinion be open and transparent.

As a community we sit at the boundary between professional communications and a hobby and we often use the idea and concepts of a contest to argue that this is the best way to hone skills and to make you a better operator in case of an emergency, but if you cannot actually learn from your mistakes, if there is no discussion on how decisions are made, if there's nothing beyond simple answers, then are we really striving for improvement or just set in our ways?

For the record, I think that if a contest log is off by 45 minutes throughout the entire log, software should pick that up, award the contacts and point out the mistake to the person who didn't set their clock correctly, especially since time is not exchanged during any contest I know. I also think that if a station logged what was actually said, there is room for that to be considered a valid exchange, but then I've only been an amateur contester for a decade, so I have plenty to learn.

I'm Onno VK6FLAB

Share if you care...

Sat, 07/17/2021 - 12:00
Foundations of Amateur Radio

When you explore the landscape of amateur radio you'll discover an endless array of innovation. There's websites with photos and descriptions of activities, places discovered and lessons learnt. If you watch the growing collection of YouTube channels you'll discover videos describing what people have been up to, commenting on videos they've seen and you'll start to notice that people all over the community are pinging off each other. Social media does the same.

If you read an amateur magazine, or a book, you'll unearth references and counter-references, links and credits, descriptions gleaned and tests made, all of them interlinking and adding to the knowledge base that underpins the amateur radio community and society beyond it.

The same is true for on-air activity. Look at contesting for example, you'll hear descriptions from other contesters, sharing their lessons learnt which potentially influence how you do your next contesting activity. The same is true for working DX, operating any digital mode, running an on-air net, running a SOTA activation, anything.

The point being that you are influenced by others and everything you do influences somebody somewhere else who in turn influences the next person who might then influence you. On and on the chain grows.

This chain of knowledge goes back to the early science in our hobby, the works of James Clerk Maxwell who for the first time brought electricity, magnetism, and light together as different manifestations of the same phenomenon in 1864.

The reason we know this is because he published his work and without needing to leave home to see the original, anyone can read it today from the comfort of their living room thanks to the PDF that's on the Royal Society web-site.

The point being that Maxwell documented his work and shared it with the world.

In our hobby we've gone through the process of making our equipment from unobtainium, requiring that the actual components were constructed before you could actually put them together and use them for their intended purpose. We then went on the scrounge for parts from other equipment, acquiring surplus gear and through a phase where you could buy new components off the shelf and attach them to an etched circuit board. That evolved into being able to design a board, ordering it online, having it built for cents and shipped to our door.

Today an increasing component of our hobby evolves around software with its unique property of transience.

Unlike physical components, software is intangible. You imagine how something might work, you describe it in an imaginary language, convert it into something that can be run inside a computer, and if you did it right, the outcome gives you the basis for your next experiment.

When software reaches a certain level of complexity it becomes impossible to remember. You tweak something over here and something over there changes and unless you can keep all that together inside your brain as a cohesive imaginary model, you quickly run into a brick wall.

If you're a software developer you've likely heard of tools like CVS, SVN and git. They are examples of revision control. They're used extensively in software development, but increasingly they're being used to track changes in documents, legislation and places where change is constant.

As an aside, if you load the various versions of legal requirements of your license into revision control, you'll quickly discover that your license is slowly evolving over time, for better or worse. From personal experience, I know doing that for the Radiocommunications Licence Conditions in Australia was very interesting indeed.

Each of these tools gives you the ability to tweak something, track it and if it doesn't work out, revert to where you started your experiment. It's a little like using a soldering iron and a soldering wick, physical undo for experiments.

When I talk about Open Source software, I'm not only talking about the ability to look inside and add functionality, I'm also talking about accessing the history that goes with that.

Open Source software generally only works if it comes with a revision history, a trail of discovery outlined right there on your screen showing what worked, why and how it came about. There's often options for showing who made what change, which changes happened at the same time and the ability to extract that particular change. All essential ingredients for experimentation.

Closed Source software does all those things, but privately. It too likely uses revision control tools, even the same ones as Open Source, but the discoveries are held in-house, behind closed doors, used by a select few. The software evolves inside the organisation, but there's no insight for or from the outside world.

Of course, everyone is entitled to keep their stuff secret, but if you want to make a contribution to society outside the life of your walled garden, the only way forward is to publish and share your work like scientists have been doing well before the Royal Society held its first meeting on the 28th of November 1660.

Share if you care...

I'm Onno VK6FLAB

What Open Source means to our hobby and why it's important.

Sat, 07/10/2021 - 12:00
Foundations of Amateur Radio

For much of the past month I've been attempting to articulate what Open Source Software is, why it's important, how it's relevant to our hobby, how it works, how software is different from hardware and why you should consider if the equipment you buy comes with source code or not. I'm finding it difficult to separate out the issues since they all hang together in a cohesive clump of ideas and concepts.

So, let me go sideways to set the scene.

There is a movement that asserts the right to repair our own things and to ensure that manuals and diagnostic tools used by manufacturers are made available to the public.

For many radio amateurs that might sound quaint and obvious, since for much of the hobby that kind of information was not only available, it was expected and assumed to be available. You can get the circuit diagram and testing procedures, the alignment process and the list of required test equipment for most if not all amateur transceivers today and truth be told, if that testing gear isn't available, we tend to build or scrounge our own.

Compare a Yaesu FT-857d and an Icom IC-7300. They're radios from different generations, use different technologies, are made by different manufacturers and come in different packaging.

Both radios have user manuals, circuit diagrams and documented testing and alignment processes, but they're not equivalent even if they look the same.

The 857 is constructed from discrete components and circuits. There's a microprocessor on-board, the source code is not available and updates are issued by the manufacturer if and when it sees fit. Its function is to control and sequence things, selecting band filters, switching modes, updating the display and control serial communications. While integral to the functioning of the radio, the microprocessor itself is used for command and control only.

Inside the 7300 you'll also find discrete components. There are circuits, filters and the like and while individual components have reduced in size there are many of the same kinds of functions inside the radio as you'll find on an 857. The microprocessor inside the 7300 is more advanced than the one inside the 857. The source code is also not available and updates are issued by the manufacturer when it sees fit.

If that was all there was to it, I would not have spent a month attempting to capture this. Suffice to say that looks are deceiving.

The microprocessor inside the 7300 does the exact same things as the 857 with one minor difference. It now also forms part of the signal input and output chain of the radio itself.

Let me say that again.

The computer that is the heart of a modern radio is an integral part of the signal processing of the radio. Where in a traditional radio the microprocessor was switching circuits on and off to process the signal, the modern solution is to do all the signal processing using software inside the microprocessor itself. If you want to get technical, an FPGA is doing much of the signal processing, but that too is driven by software.

Where previously you had access to the circuit diagram that would show you what was being done to the signal, today you have a magic black box that does stuff completely outside your control.

If you want to know how an SSB or FM signal is decoded on the 857, the service manual will helpfully point you at two chips which provide those specific functions. It describes how the signal comes into the chip and how the signal is processed once it leaves the chip and if you need more, you can look online to find the specifications for each chip to see precisely what they do and how they work, complete with equivalent circuits and specifications.

On the other hand if you wanted to know the same information for the 7300 you'd be out of luck because if you dig deep enough, following the signal path, eventually you'd end up inside the microprocessor where software is making that happen. There's no description on how this works, what the circuit equivalent characteristics are, there's no way to change how it works, no way to set parameters, no way to see inside and no way to experiment.

This is a problem because it means that you've got a solution that's no longer operating in the spirit of amateur radio. It's not open for experimentation, it's not subject to review, there's no way to test, no means to improve, no way to do anything other than what the manufacturer decided was appropriate.

For example, if I wanted to modify the FM pass-band width on an 857, I could update the FM demodulation circuit by replacing a couple of components. On a 7300, I could not because there is no circuit. The FM demodulator is described in software that I don't have access to and Icom has decided that the FM pass-band is fixed.

If the software was open however, I could add this function and make it available to anyone who would like to experiment.

At this point I'd also like to observe that the Icom user manual states that inside the IC-7300 it uses open source "CMSIS-RTOS RTX", "zlib" and "libpng" software, so Icom is benefiting from open source efforts, but not sharing their own.

This is not an Icom only problem, this is a specific issue around open source versus closed source and while you might think that the right to repair and open source is something that's not relevant to you, I'd like to invite you to consider what the implications are for our hobby. Are we going to go down the road of button pushers, or are we continuing our role as inventors and experimenters?

I'm Onno VK6FLAB

What mode is that?

Sat, 07/03/2021 - 12:00
Foundations of Amateur Radio

The hobby of amateur radio is about communication. When you go on-air and make noise, you initiate a communications channel, sending information out into the world and hoping for another station to receive and decode what you sent. The channel itself can be used in an infinite number of ways and each one is called a modulation mode, or mode for short. The popular ones come with most radios, CW, AM, SSB and FM.

Those few are not the only ones available. In fact as computers are being integrated into the radio at an increasing pace, signal processing is becoming part and parcel of the definition of a mode and new modes are being introduced at break neck speed. I've talked about WSPR as an example of one such mode, but there are many, each with their own particular take on how to get information between two stations.

As you listen on the bands you'll increasingly find yourself hearing a bewildering litany of beeps, pops and clicks. Some of those are due to ionospheric conditions, but many are different modes that are being experimented with across our spectrum.

If you have access to a band scope, a way of visualising radio spectrum, you can actually see the shapes and patterns of such signals over time and getting to that point can be as easy as feeding your radio audio into your computer and launching a copy of fldigi or WSJT-X.

Every mode requires a specific tool to decode it and with practice you'll discover that there is often a particular look or sound associated with a mode. Over time you'll confidently select the correct decoder, using your brain for the process of signal identification.

Of course if you don't have access to the library in your brain yet, since you've only just started, or if the mode you've come across is new, you'll need another library to discover what you found. There is such a library, the Signal Identification Wiki. It's a web-site that hosts a list of submitted signals, grouped by usage type, including one for our community.

On the amateur radio page of the Signal Identification Wiki there are over 70 different modes listed, complete with a description, an audio file and a spectrogram. With that you can begin to match what you've discovered on your radio to what the web-site has in the library and determine if you can decode the incoming information.

I will mention at this point that the Signal Identification Wiki is far from complete. For example, the Olivia mode has 40 so-called sub-modes of which about 8 are in common use. Each of those sub-modes looks and sounds different. The wiki shows only a single line for Olivia.

I'm pointing this out because the wiki allows you to submit a mode for others to use. If you have a signal, either by recording it off-air, or better still, recording it directly from the source, consider submitting it to the wiki so others can benefit from your experience.

If you've come across a signal and you cannot figure out what it is, there are other places you can go for help. The four and a half thousand members of the /r/signalidentification sub on reddit will happily look at and listen to your signal and try to help. Make sure you contribute some meta data like the time, frequency and location to accompany the spectrogram and audio.

You might have come to this point wondering why I'm encouraging you to use and contribute to the wiki and ask for help on reddit. Amateur radio is about experimentation. We love to do that and as we make signal processing easier and easier, more people are making new modes to play with.

The speed at which this is happening is increasing and as an operator you can expect to come across new signals. I remember not that long ago, it was last month, tuning to an FT8 frequency and the person I was with asking what that sound was. They'd heard it before but never discovered its purpose, even though FT8 has been with us since the 29th of June 2017.

What interesting signals have you come across and how did you go with decoding them?

I'm Onno VK6FLAB