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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: 3 hours 23 min ago

When I said Parrot Repeater ... I likely had a different picture in mind.

Sat, 01/15/2022 - 11:00
Foundations of Amateur Radio

A little while ago I mentioned in passing that I was considering implementing a parrot repeater to help determine how your radio is performing. Discussion afterwards revealed that not everyone had the same picture in mind, so I thought I'd share with you some of what I'm considering and why.

Most of the modern radio landscape revolves around hooking a computer up to some type of radio frequency capable device. Commonly it's the audio and control signals that travel between computer and radio, but there are plenty of examples where raw data makes the journey, like in the case of an RTL-SDR dongle.

That journey is increasingly made using USB, the cable, not the sideband, and limits are based around the maximum speed that a Universal Serial Bus has. Essentially the amount of data that you can process is limited by how fast your computer can talk to the radio.

For my parrot repeater, I'm imagining a device that can receive RF from any radio and process that signal to determine what the centre frequency is, the deviation, stability, the mode, what ever parameters I end up being able to determine, a whole other discussion on its own. In response, the idea is that the device generates a report and either presents that using text to speech, or as a web-page, or both.

Using traditional methods, this would involve a radio, a computer, some software, connections between the radio and the computer, not to mention power for both the computer and the radio, an antenna and perhaps an amplifier. The picture I have in mind is not anything like that. I'm imagining a single device that takes power and does all I've described inside the one device. No external computer, no audio cables, no control cables, no hard drives, not anything, just a PlutoSDR and a power source connected to an antenna or two.

You might think that's fanciful. As it happens, we already have some of that today. When I run dump1090 on my PlutoSDR, it presents itself to the world as a website that I can visit to see which aeroplanes are within range, where they are exactly on a map, what messages they're sending and where they're going. All of the processing is done inside the PlutoSDR. All I have to do is give it power and an internet connection.

This is possible because the PlutoSDR is essentially a computer with RF. It runs Linux and you can write software for it. Unlike my Yaesu FT-857d, which also has a computer on board, rudimentary to be sure, but a computer none the less, it cannot be altered. I cannot load my own piece of software, launch a web browser and point it at my Yaesu, not without connecting an external computer that in turn needs to be connected to the radio. I might add, that this is is how many repeaters work and how devices that implement AllStar and Echolink manage to make the jump between the Internet and the world of RF.

If your eyes are not lighting up right now, let me see if I can put it in different terms.

The PlutoSDR has the ability to access signals between 70 MHz and 6 GHz. It can do so in chunks of 56 MHz. Said differently, if you were able to consider all of the amateur HF spectrum, from zero to 54 MHz, you could fit all of it inside one chunk of 56 MHz that the PlutoSDR is capable of. You couldn't send it anywhere, since you're limited to how fast a USB cable is, but you could technically process that inside the PlutoSDR itself.

To get the PlutoSDR to see the amateur HF bands you could connect it to a transverter, in much the same way that today many 2m handheld radio owners use a transverter to get to 23cm, except in this case, we're going the other way.

In order to actually use this massive amount of information, you're going to need to do some serious signal processing. Accessing 56 MHz of raw data is hard work, even if you don't have to get it across a serial connection. As it happens, the PlutoSDR also comes with an FPGA. As I've mentioned previously, it's like having a programmable circuit board, which can be programmed to do that signal processing for you. It has the capability to massage that massive chunk of data into something more reasonable. For example, you might be able to use it to extract each of the amateur bands individually and represent them as an image that you might show to the world as a waterfall on a web browser.

Now to be clear, I'm not saying that any of this exists just yet, or fits within the existing hardware constraints. I'm only starting on this journey. I'll be learning much along the way. No doubt I'll be using existing examples, tweaking them to the point that I understand what they do and how they work. I've already been talking about some of this for years. As you might have discovered, this adventure is long with many different side quests and at the rate I'm going I'm confident that this represents the breadth and depth of what amateur radio means to me.

So, if you're wondering why I'm excited, it's because the amateur radio world of opportunity is getting bigger, not smaller.

I'm Onno VK6FLAB

Products made from unobtainium

Sat, 01/08/2022 - 11:00
Foundations of Amateur Radio

The other day I received an email from a fellow amateur, Elwood WB0OEW. We've been exchanging email for a little while and having been in the hobby since before I learnt to ride a bicycle, he's always got some interesting insight into something I've said and an encouraging word to share.

This time he introduced me to a project he built and published a couple of years ago. It's a variable frequency standard, built from parts and, at the time, costing all of about $150, more on that shortly. Compared to the microwave oven sized HP-606A signal generator sitting on my bench in bits, with some diligent layout, this project could fit inside one of the valves that drives that massive hunk of equipment.

As an aside, truth be told, I'm a little afraid of the HP. It managed to pop the RCD, a residual current device, or safety switch, in my house and in doing so, took out the UPS that powers my main workstation, so, not unexpectedly, I'm reluctant to repeat the experience. Once I understand precisely what happened, I'll pick up the restoration efforts and based on what I learnt today, it might get me where I want to go faster.

Elwood's frequency standard is a very interesting project that delivers a very precise Variable Frequency Oscillator or VFO with an accuracy approaching 1 part per billion. His project uses an Arduino to control a touch sensitive display, read a knob and set and correct the frequency using a GPS as an accurate external time source. It's all very compact, easy to follow and I immediately thought that this would be an excellent project to build with a little twist.

I'm thinking that it would be really great to have this device sit on your local network and make it remote controllable.

The heart of this frequency standard project is a chip called an Si5351. The Silicon Labs Si5351, to use its full name, was first sold by Mouser in 2010 and has been popular since. You'll find it in all manner of places, including the Linux kernel source tree, the QRPlabs QCX and BITX to name two, the Elecraft KX2, scores of Arduino projects and countless frequency source products and projects used in amateur radio.

The Si5351 is a configurable clock generator. Think of it as a programmable crystal that can be configured on the fly, as often as you like. For configuration, it uses an I2C bus, or Inter-Integrated Circuit communications protocol, a special serial bus intended for chip to chip communications, invented by Philips Semiconductors in 1982. That's the same Philips from the light bulbs and audio cassettes, CD, DVD and Blu-ray, also the Philishave. To complete the picture, Philips Semiconductors became NXP in September 2006.

Back to our frequency standard project.

I wondered if I could cut out the Arduino from the actual correction process, since I didn't need a display or a knob and discovered that the Si5351 comes in several flavours. Elwood's design uses the A-version, but there's also a C-version that has the ability to take in an external clock, like say that from a GPS, and correct within the chip itself.

With that information in hand, I figured that I could use a simple Wi-Fi capable system on a chip, something like say an ESP8266, to configure the clock and take care of communications with the outside world. In the process I'd learn how to do a bunch of new things, including my first foray into generating RF, first time writing actual firmware, first time designing circuits and no double many more firsts.

Then I hit a snag.

It seems that the Si5351 has gone from commonplace to zero in stock. Not just zero in stock in Australia, or the US, no, zero in stock anywhere. There are a few A-version breakout boards, that is, the chip on a circuit board, available from one supplier. There is also a new compatible chip, an MS5351M, available from China, but that's a drop-in for the A-version, not the C-version.

So, where it stands is that I can almost taste the design, essentially three chips, an almost trivial circuit board, some SMA connectors, a power source and an external GPS antenna, something that would represent the very first circuit I actually designed, which is a long way from reading the circuit diagram for my Commodore VIC-20 back in the days before I owned a soldering iron.

It did bring me face to face with an odd realisation.

There are components that we use in day-to-day use, ones that are common, used across many different industries, that come from a single source. I should also mention that this particular manufacturer just got sold to another company, which doesn't help matters.

Nobody seems to know how long this shortage might last with forecasts varying wildly, but I'm beginning to wonder how many of these kinds of components exist and how we might reduce our dependence on single supplier hardware.

I'm also starting to look at using an FPGA to do all of this in software, but that's going to take some time, of course we could start using valves again. My 1960's era HP signal generator is starting to look much less intimidating.

I'm Onno VK6FLAB

Leaving the hobby ...

Sat, 01/01/2022 - 11:00
Foundations of Amateur Radio

The other day I came across a how to video on becoming a radio amateur. It's a recurring kind of publication, the kind that I've contributed to in the past.

I wondered what it would take to leave the hobby.

First of all, I'd have to let my callsign lapse. That's easy enough, but I paid for five years, so it's going to take a while. When it has finally ceased being mine, have I stopped being an amateur?

For one, my qualifications would still be in the regulator's database, likely well beyond my breathing years. I wonder if they implement the right to be forgotten?

Another thing I'd have to do is stop knowing about how antennas work in day-to-day situations. I'd have to stop noticing the location of free to air television antennas, mobile phone towers, Wi-Fi antennas throughout the community and even the network in my home.

I'd also have to say goodbye to all the friends I've made around the place. There's hundreds of people scattered around the globe who with a single word might lure me back into their world, and with that the risk of being sucked back into the community once again.

At a minimum I'd have to stop using computers, or radios, or electronics really. I'd have to stop wanting gadgets and measuring equipment, not to mention having to mothball my soldering irons and give away all my heat shrink.

I'd have to give back the space I've eked out in the house and return it to the general living space it once was. I'd also have to sell all my radio gear and antennas. I'd have to rip out the coax, fix up any holes, cancel pending orders for new antennas and donate my books and magazines to the local library.

I'd have to stop looking at electronics magazines, cut up my loyalty cards for the local electronics and hardware stores and start an online store to sell all the connectors and adaptors I've amassed over the time I've been part of the community.

I'd have to forget the phonetic alphabet that I use almost daily and start using crazy words to spell things over the phone like a normal person does.

Experimentation would be a thing of the past and would be frowned upon as a fringe activity, one only suited to madmen and amateurs, and I'd have to stop investing my time in software and projects that might one day be used in amateur radio.

One of the hardest things to give away would be my curiosity, the one thing that's innate to my wellness. I'd have to stop asking Why? and How? all the time. I'd have to plead ignorance when someone asks how coax works and what's inside a blob of goop on a random circuit board they found on the side of the road.

Then there's the other things like physics and general science. I'd have to disavow all knowledge of these activities. I'd have to stop looking at the stars and stop wondering which radio frequencies were being emitted from all over the night sky.

I'd have to become ignorant of emergency services and communication, of event management and club life. I'd have to feign interest in anything that wasn't science or technology and I'd have to keep a straight face and my mouth shut when someone extolled the virtues of an irrational belief system.

I would likely have to give up my job as an IT consultant and start on a more manual job. Perhaps I'd take up gardening, though I'm not sure how I'd do in the weather at my age.

Even if I achieved all that, and kept it up for the rest of my life, I'd still be an amateur, just one hiding from the hordes of humanity striving to live on this ball of dirt, hurtling through the heavens on a journey through the stars.

I'm not sure I could do that.

So, for better or worse, as I see it, once an amateur, always an amateur and if you're curious and believe in science and technology, I'm here to say that you're well over halfway towards being an amateur! Welcome to the club!

I'm Onno VK6FLAB

What testing equipment is essential?

Sat, 12/25/2021 - 11:00
Foundations of Amateur Radio

After discussing the notion that it's not really possible to determine how your gear is performing without measuring, several people commented that in the good old days an amateur was expected to have sufficient equipment to test performance of their gear.

I flippantly pointed out that once upon a time, computers ran on punch cards too. That's not to dismiss the notion of testing, but rather that times have changed. Testing equipment that was suitable in the 1980's is still available around the place, but expect to pay for it. Some of it is still relevant, some less so.

Even if you do acquire suitable equipment, how do you know if what you're measuring is real? How do you know if the frequency counter that you have is accurate, how do you know if 1 Volt is 1 Volt, or 1 second is 1 second? As I've said before, measurement is the act of comparing two things.

If you think that's ludicrous, consider the rulers and tape measures in your home. They all indicate the same measurement, right? Just for a laugh, pull out all the ones you can find and see what you discover. If you've not done this, you're in for a surprise.

I don't want to dissuade you from getting testing equipment, far from it, but don't expect to fork out to get the equipment and call the job done. The point being that spending lots of money on gear isn't the end of the story, it's just the beginning and in my opinion it's not the place you should start.

Based on community responses, ninety recommendations in all, so hardly scientific or representative, but still a good feel for the space we're playing in, the single most important piece of equipment you should get after sorting out your radio, antenna, coax, power supply, computer, software and other fun things we fill our shacks with is the Digital Multi Meter. You can spend anywhere from $10 to $500 on one, but it should be high on your list. As with the rulers, your results will vary, so be mindful of that when you go shopping.

While the SWR meter and the Watt or Power meter appear regularly, they're not the next highest ranked testing gear. Mind you, most current radios have those built-in to some extent, so perhaps the numbers are somewhat distorted here.

The next essential piece of equipment is some form of monitoring. Either active, passive, programmable, automated, manual, what ever. Hardware like the NanoVNA, the TinySA, even using a Software Defined Radio feature high on the list. Most of these devices either generate a signal to test against, or they rely on your radio to do the heavy lifting, depending entirely on what you're testing. An antenna analyser is among these kinds of tools.

As an aside, the dummy load, either a high power one, or a more modest one, come recommended by many different people.

Together with this list of monitoring equipment comes associated accessories, adaptors, patch leads, attenuators and filters.

After that comes equipment such as variable power supplies, Watt meters, grid dip meters, oscilloscopes and frequency counters.

I will observe that from the responses I received there was a distinct flavour to the recommendations.

On the one hand there was the combination of recommending something like a station monitor, or a signal generator, an oscilloscope and a frequency counter, including things like a Bird 43 RF Watt meter. On the other hand were recommendations for spectrum analysers, NanoVNAs, SDRs and the like. It's not quite across the analogue to digital divide, but it's close.

Note at this point that I'm a software guy in the process of restoring an analogue HP 606A Signal Generator from the early 1960's, so I'm not pointing the finger anywhere.

There were other tools recommended too, an LCR meter, a tool that allows you to measure Inductance, Capacitance and Resistance, something you can buy in kit form if you want to get started, or similarly, can be purchased for varying amounts of money online. Speaking of money, varying amounts that is, the service monitor was on the wish list for several people. Prices between that of a new radio or a new car with varying amounts of warranty.

I will make mention of a bi-directional coupler which was marked as essential by one amateur. It's a tool that allows you to sample a signal in the forward and the reflected path which comes in handy when you're trying to test and build equipment.

As mentioned before, your transceiver has some of this equipment built in, or can be set-up to do some of this, so there's no need to go out and spend thousands of dollars to set-up your testing bench on day one, but the day after, I'd add it to my birthday list.

No doubt that there's many and varied opinion on this. What is your essential testing equipment?

I'm Onno VK6FLAB

How does your gear measure up?

Sat, 12/18/2021 - 11:00
Foundations of Amateur Radio

When you spend some time in this hobby you're likely to find equipment with similar performance for vastly different pricing. At one end of the spectrum you might compare a cheap $25 hand-held radio to a $450 one. At the other end, a $1,500 SDR or Software Defined Radio against a $4,500 one.

Those examples are for brand name devices, which generally speaking have published specifications, come with regulatory approvals, a wide user base, reviews and a distribution network. If equipment is found to be operating out of specification, a regulator might seek a remedy or ban the sale of the equipment.

Those various sources and processes make it possible to compare those devices in a structured way to discover just how deep into your pockets you need to reach in order to acquire a shiny new gadget.

If you buy any of these devices in the used market, you have no way to determine just how far from the factory specifications the device you're contemplating has deviated. Is that waterproof radio still waterproof, or did the previous owner open up the case and put it together incorrectly? Was it dropped and did a component get damaged? Did the static electricity from a local thunderstorm leak through the circuit via the antenna, or did the previous owner not use anti-static precautions when they looked inside?

If it actually failed, it's easy to know. If it's still working, absent a laboratory, you're essentially on your own.

If that's not challenging enough, consider hardware that's released as open source, that is, the original designer released their project, shared the design, a circuit board with component list and specifications. Another person can pick up the documentation and legally build a copy of the hardware.

How do you know how the two compare?

Aside from considering how well any design might actually match the real world, how do you know if the original design can be improved upon or not? Did the second builder use the same components, substitute with better ones, or economise on parts they thought were too expensive?

What happens if the two designers argue with each other about the performance of their respective designs? What if the second design becomes vastly more popular than the original and what if you throw in outright intellectual property theft over the top of all this?

Now consider the same physical hardware, from the same factory, but using different software. How do you know what impact the software has on the performance of the equipment? For example, one component seen more and more is a chip called an FPGA, a Field Programmable Gate Array. Think of it as a programmable circuit board where updating the software creates a different circuit.

An FPGA might be used to filter radio signals. With just a software update, you can program different filters and change the actual performance of the entire device. How do you know if the new version of the software has improved or worsened performance?

What all this lacks is a standard way of describing performance. Not only the kind of standard that's achievable in a laboratory, but one that we can test at home. There's no documentation that I've been able to find that shows how to measure some of this objectively, or even compare your own kit against itself.

It would be great if I could measure my gear against a standard and you could too and we could compare our respective equipment against each other.

Even using the laboratory standard measurements, for example the Sherwood Engineering Receiver Test Data, which allows you to compare other tested equipment in the same list, is hard, if not impossible to compare at home by the likes of you and I. Not to mention that Rob NC0B has finally retired after 45 years, so having been licensed in 1961 age 14, there is a good chance that updates are going to become a thing of the past when Rob stops volunteering his time.

I will mention that this isn't a new thing. Many years ago I spent some time as a broadcaster. One of the very first things I was taught is that you need to set levels to trigger the VU Meter just so. When you make a recording to tape, you're required to generate a 1 kHz tone at a specific level so when it's played back to air, the voice levels will be correct.

When I became licensed in 2010 I almost immediately discovered that there isn't even a standard way to test if the signal that my radio is putting into the local repeater is the same as that of other amateurs. You'll notice this because you're forever twiddling the volume on your radio when you speak with others on-air because their voice levels vary widely.

One idea I've been toying with is using a parrot repeater that can measure a signal, allowing anyone who uses the same parrot to compare their equipment.

How would you approach this increasingly complex problem in such a way that the amateur community can share their results in a way that makes comparison meaningful and useful?

I'm Onno VK6FLAB

Getting Amateur Radio propagation data at home

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

For some time now I've been discussing the potential of weak signal propagation and its ability to create a live map from the data that your own station transmits. There are several systems in place that show a map of where and when your station was heard in the past little while. Using 200 milliwatts, I've been transmitting a WSPR or Weak Signal Propagation Reporter beacon on 10m for the past few weeks.

At the moment, the furthest away my beacon has been heard is 13.612 km away. That's an 0.2 Watt signal heard on the other side of the planet, on 10m. As distance goes, it's a third of the way around the globe. I must point out that there's no way of knowing if this signal travelled the short path or the long path.

If you've heard those terms, short and long path but were wondering what they mean, here's how it works. If I get on my bike at my QTH in Perth in VK6 and peddle East until I hit Sydney, I'll have crossed Australia, taken about 184 hours and travelled about 3.746 km. That's the short path. If I head West instead and start swimming, visit Cape Town, Buenos Aires and Auckland along the way, I'll have travelled much further, still made it to Sydney, but taken the long path.

Radio waves can do the same. Depending on propagation, a signal might take either the shortest route, or go in the opposite direction and take the longest route along the great circle between two stations.

I'm mentioning this because WSPR doesn't tell you if it's one or the other and if you're using a vertical, it could be either. Even directional antennas might receive a signal from unexpected directions.

Using one of the mapping tools, wspr.live, I extracted all the sightings of my callsign and all the reports that I'd made from my receiver. It shows that my newest transmitter has now been heard by 11 stations across three continents.

Those numbers are just the beginning. I wanted to see on the map where these stations were, so, during the week I built a proof of concept world map that I used to visually show the four character Maidenhead grid squares that my station was heard in. I also had a look to see which stations I'd heard over the years and where they were. In all, 771 different stations are in my log, either as a receiver or a transmitter.

N4WQH heard me on 40m, 18.832 km away when I was using 5 Watts. My station has heard, or has been heard across 331 different grid squares. There's reports across some remote parts of Australia, Japan, India, South Africa, Europe, the United States, several across the Pacific and even a few in Antarctica.

I wondered how many of the world's grid squares have actually been activated and which station was heard the furthest and how much power was used. Those numbers will have to wait for another day. I initially started using wspr.live which has a neat way of allowing you to embed an SQL query as part of the URL to download the output.

I was getting some interesting results, so I thought, rather than hammer this lovely resource with my questions, I should download the raw data instead. So I did. Well, I am. Still. It's big.

As of today, there's 166 files, taking up 60 GB of compressed data, with over 3.5 billion reports.

The first spot in that data goes to N8FQ who heard WB3ANQ on Monday, the 17th of March, 2008 across 911 km on the 30m band transmitting with 28 dBm, or about 630 mW, reporting a signal to noise ratio of 1 dB.

Using preliminary data to get started I mapped all the activated squares, each shown as a red box and saw that my entire map was red. At that point I figured that either I've got a bug in my code, or something else is going on.

To give some context before I share what I found, a Maidenhead locator consists of a combination of letters and numbers. For four letter grid squares, there's a grand total of 32.400 different combinations, running from AA00 to RR99. They're 2 degrees wide and 1 degree high and their width depends on where on the planet they are. At the equator it's about 222 km wide and 111 km tall, at the North and South pole, it's 0 km wide. If you travel between two squares, you might have to move a meter, or the entire width of a grid square.

Among the report, I found stations who had activated more than one square. That's fair enough, you can move your station and start making noise where ever you like. I found stations with activations across more than a thousand different squares. Before I start pointing the finger, I will mention that if you attach a WSPR beacon to an aircraft, or a balloon, you can legitimately activate plenty of squares.

When you set-up a WSPR transmitter, you're required to manually enter the locator and mistakes happen. There's plenty of records with invalid Maidenhead locators, typically shown instead is a callsign. Then there are stations that pick desirable locators. This manual entry is also true for the power level and even the callsign, so I'm not outing these stations here, since it's entirely possible that the callsign shown doesn't actually relate to the transmitter or the licensed amateur.

What does all this mean?

It means that the information in the WSPR database cannot be trusted. I suspect it also means that the data used to lodge FT8 contacts across the planet can probably also not be trusted. It means that any propagation data you're deriving is likely contaminated by misreporting, deliberately or not.

As a community, if we want to use this for actual measurements, we'll have to figure out how to make this a trusted resource, because the information that WSPR can bring to propagation is in my opinion extremely valuable.

I would love to hear your thoughts on how we might fix it.

I'm Onno VK6FLAB

Amateur Radio and the art of getting started ...

Sat, 12/04/2021 - 11:00
Foundations of Amateur Radio

One of the regular topics of conversation in amateur radio, especially for those new to the community, is where to start? The sheer volume of available options is often overwhelming. If you've never encountered the complexity associated with this amazing hobby the experience can be disheartening and even demoralising.

In my early years I was results driven. Getting on air, making noise, logging a contact, adding a country, winning a contest, rinse and repeat, get better, do more. There have been numerous occasions when I came home from one of my adventures disappointed, sometimes bitterly so.

That happened for quite some time, until one day I realised that the journey in and of itself is the reward.

That might sound disingenuous, so let me illustrate.

This week I set-up an automatic beacon in my shack that can be heard by stations around the planet, letting me know just how far my signal can travel at any particular moment, using my own station antenna and local propagation. As projects go, it continues to be an adventure.

As you might recall, I like low power operation, truth be told, I love low power. The smaller, the better. Less is more and all that. I recently completed the first leg of a journey to set-up a permanent beacon. For years I'd been dabbling around the edges. On the weekend, whilst I was in my shack, I'd regularly set-up my computer and radio, set it to WSPR beacon and see what stations heard me. I couldn't turn my radio below 5 Watts, so that's what I used. Before you start, yes, I could turn down the volume, but that involves math and I wanted a result, now.

It filled a gap using WSPR, Weak Signal Propagation Reporter, like that. For a while, I improved on things by having a receiver set-up that monitored the bands all day every day and recently I turned it back on, with limited success, more on that shortly.

What I really wanted was to see where my signal was going, not what I could hear. I received a few emails suggesting that a ZachTek WSPR Desktop transmitter, built and sold by Harry, SM7PNV, would be just the ticket. It's a little metal box with USB and SMA connectors. One SMA for the supplied GPS antenna, used for location and time, the other for a transmit antenna. USB provides serial for configuration and power if it's operating in stand-alone mode. Yes, you can operate it without needing a computer and if you want it does band-hopping. After configuring it with things like your callsign and bands, you can plug-in the GPS, your antenna and power it via USB and it will run as an automatic 200 milliwatt WSPR beacon.

That device in turn prompted a journey to discover a more appropriate antenna, since my current station antenna uses an automatic tuner that won't get triggered by this tiny transmitter. That caused an exploration in how and where to mount any new antenna, with a side-trip into finding a specific anti-seize compound locally. To pick the mounting hardware, I had to get into wind loading, how strong my satellite dish mount might be, how to install and tune a multi-band antenna. The list just keeps growing and that voyage continues.

I'm tracking the requirements with a project specific check-list, just to make sure that I don't miss any steps and have a place to document new discoveries when they invariably hit me in the face. So-far, so-good.

The WSPR monitor receiver is currently connected to a generic telescopic dipole, mounted indoors, which in the past gave me a much better result than my station vertical, so I should be able to keep both running.

Next on the list is to construct a live propagation map for my station, then a way to switch modes on that map, so I can tell if it's worth calling CQ without going blue in the face. I'm also working on a WSPR transmitter for 2m and 70cm, because they are under served in my neck of the woods.

The takeaway from all this is that whilst there are many steps, and truth be told, that list is growing as I learn, each step is tiny and doable. The only thing that separates me from someone who doesn't know where to start, is this.

I started. You can too. Anywhere. Doesn't matter. Pick anything that tickles your fancy. Start digging. It's a hobby, not a profession. What ever floats your boat, what ever makes you excited, what ever you're interested in, pick it and do something, anything.

That's how you get anywhere in Amateur Radio, and Open Source, and life for that matter, just start.

I'm Onno VK6FLAB

One Timezone To Rule Them All

Sat, 11/27/2021 - 11:00
Foundations of Amateur Radio

Right now it's 10:45.

That piece of information is unhelpful without any context. I could just as easily have told you that it's 2:45 and it would be just as accurate, helpful and meaningless. The point being that without context, you don't know if I'm an insomniac, drinking morning tea, recovering from a late lunch or putting on my PJs.

If I'm talking to people in the same room, supplying the time happens within the context of that room, but if the world is our oyster, our room is a little larger and dawn for one person is dusk for another, at the same time.

Before we could communicate at the speed of light and travel faster than a bullet, time was a relative thing related to the location of the Sun and considered mainly by mariners and astronomers. Even with the advent of increasingly accurate clocks, for most people, noon was when the Sun was at its highest point and the local clock was set to that.

When our world got smaller, because communication and travel got faster, people started noticing that noon in one place wasn't the same as noon in another place. It became a real problem when people travelled hundreds of kilometres by train in a day. Imagine coming up with a train time-table that takes into account each local version of noon.

In an attempt to deal with this, railroad managers in the United States established 100 railroad time zones. This malarkey continued until the 18th of November 1883 when four standard time zones were established for the continental United States.

Of course, being human and all, that was a local solution. Great Britain had already established its own standards for time for England, Scotland and Wales.

In October 1884, the International Meridian Conference, held in Washington DC, adopted a proposal that designated the Prime Meridian for longitude and timekeeping should be the one that passes through the centre of the transit instrument at the Greenwich Observatory in the United Kingdom and established Greenwich Mean Time, or GMT as the world's time standard.

Why Greenwich? At the time the United Kingdom had more ships and shipping using Greenwich as their reference than the rest of the world put together and the observatory at Greenwich had produced the highest quality data for a long time. As an aside, on a French map before 1911, 0 degrees was centred over Paris. There are other wrinkles, like the fact that Earth isn't round and as a result the Greenwich Prime Meridian is not quite in the right spot because measurements didn't take into account local variations in gravity.

In 1972, Coordinated Universal Time, or UTC replaced GMT as the standard for time in the world. It now references the International Reference Meridian, currently about a 102.5m east of the original Prime Meridian passing through Greenwich. It's on the move with reference to land because tectonic plates shift and where it is today is not where it's going to be tomorrow, so don't go looking for a marker to indicate the IRM.

Meanwhile in the rest of the world people needed to come to terms with how to standardise on what to call time zones. The USA establishing four time zones was just for one country. Depending on who's counting, there's over 200 countries and each has its own set of time zones. Which each might include daylight saving, or not. For some, like VK6, daylight saving was voted on several times. Trials were had and time changes during summer were implemented, then reversed, then reversed again, and again, in total, VK6 did this dance six times and we currently don't observe daylight saving, neither does VK4 or VK8.

So, not only does 10:45 require location context, it also requires that you know if there's daylight saving happening at that time in that location, which to add insult to injury, doesn't actually happen on the same date each year. It gets better if you consider time in another location. Do they have daylight saving, is it on at the time, do we have daylight saving at that time, how many hours are we apart, when is this actual event and what if we're coordinating efforts between people in multiple locations? Did I mention that summer in Europe is in July and in Australia it's in January?

In case you're wondering, tracking all this is a massive job currently under the purview of the Internet Assigned Numbers Authority. The person coordinating this, whilst wrangling the politics of naming things, including dealing with warring countries who take umbrage at having their time zone named after "the enemy" is computer scientist Paul Eggert, the project lead of the time zone database.

War aside, time zones are political. For example, Dublin Time was stamped out by the British as punishment for the Easter Rising.

If that wasn't exciting enough, to provide local context, we use abbreviations to indicate which location we're talking about. In VK6 that abbreviation is WST, simple enough, Western Standard Time. What if your abbreviation was CST? Is that Central Standard Time in North America, China Standard Time, Cuba Standard Time, or even Australian Central Standard Time. If your local time zone is IST, you could be referring to Indian Standard Time, Israel Standard time, Irish Standard Time or even Irish Summer Time.

As radio amateurs we hold global contests and we advertise our online club meetings and events. Often, we refer to times and dates that might be understood by an audience of one, but utterly confusing to the rest of the world.

So, what do you do with this?

Simple, use UTC. My timezone, called WST, or AWST, is UTC+8. F-troop, a weekly net for new and returning amateurs runs every Saturday morning at midnight UTC, that's 0:00 UTC. No confusion, no daylight saving, everyone can figure out if it's worth being awake for and I must applaud the amateurs from G-land and PA with their contributions in the very, very early hours of their morning.

So, next time you make some noise about a contest, or any amateur activity that goes beyond the people in your suburb, specify the time in UTC. Who knows, perhaps one day, even the likes of SpaceX, Apple and Google will start using UTC to announce their events ...

As Goldie Hawn put it: "Well, in my time zone that's all the time I have, but maybe in your time zone I haven't finished yet. So stay tuned!"

I'm Onno VK6FLAB

The Rebirth of Homebrew

Sat, 11/20/2021 - 11:00
Foundations of Amateur Radio

On the 12th of December 1961, before I was born, before my parents met, the first amateur radio satellite was launched by Project OSCAR. It was a 10 kilo box, launched as the first private non-government spacecraft. OSCAR 1 was the first piggyback satellite, launched as a secondary payload taking the space of a ballast weight and managed to be heard by over 570 amateurs across 28 countries during the 22 days it was in orbit. It was launched just over four years after Sputnik 1 and was built entirely by amateurs for radio amateurs.

In the sixty years since we've come a long way. Today high school students are building and launching CubeSats and several groups have built satellites for less than a $1,000. OSCAR 76, the so-called "$50SAT" cost $250 in parts. It operated in orbit for 20 months. Fees for launching a 10cm cubed satellite are around $60,000 and reducing by the year.

If that sounds like a lot of money for the amateur community, consider that the budget for operating VK0EK, the DXpedition to Heard Island in 2016 was $550,000. Operation lasted 21 days.

I'm mentioning all this in the context of homebrew. Not the alcoholic version of homebrew, the radio amateur version, where you build stuff for your personal enjoyment and education.

For some amateurs that itch is scratched by designing and building a valve based power amplifier, for others it means building a wooden Morse key. For the members of OSCAR it's satellites. For me the itch has always been software.

Sitting in my bedroom in the early 1980's, eyeballs glued to the black and white TV that was connected to my very own Commodore VIC-20 was how I got properly bitten by that bug, after having been introduced to the Apple II at my high school.

I'm a curios person. Have always been. In my work I generally go after the new and novel and then discover six months down the track that my clients benefit from my weird sideways excursion into something or other.

Right now my latest diversion is the FPGA, a Field Programmable Gate Array. Started watching a new series by Digi-Key about how to use them and the experience is exhilarating.

One way to simply describe an FPGA is to think of it as a way to create a virtual circuit board that can be reprogrammed in the field. You don't have to go out and design a chip for a specific purpose and deal with errors, upgrades and supply chain issues, instead you use a virtual circuit and reprogram as needed. If you're not sure how powerful this is, you can program an FPGA to behave like a Motorola 65C02 microprocessor, or as a RISC CPU, or well over 200 other open source processor designs, including the 64-bit UltraSPARC T1 microprocessor.

I'm mentioning this because while I have a vintage HP606A valve based signal generator that I'm working on restoring to fully working. Homebrew for me involves all that the world has to offer. I don't get excited about solder and my hands and eyes are really not steady enough to manage small circuit designs, but tapping keys on a keyboard, that's something I've been doing for a long time.

Another thing I like about this whole upgraded view of homebrew is that we as radio amateurs are already familiar with building blocks. We likely don't design a power supply from scratch, or an amplifier, or the VFO circuit. Why improve something that has stood the test of time? In my virtual world, I too can use those building blocks. In FPGA land I can select any number of implementations of a Fourier Transform and test them all to see which one suits my purpose best.

In case you're wondering. My Pluto SDR is looking great as a 2m and 70cm beacon, transmitting on both bands simultaneously. It too has an FPGA on board and I'm not afraid to get my keyboard dirty trying to tease out how to best make use of that.

What homebrew adventures have you been up to?

I'm Onno VK6FLAB

Defeating the Pitfalls of Predicting HF Propagation

Sat, 11/13/2021 - 11:00
Foundations of Amateur Radio

As you might know, I like to transmit with as little power as possible, known as QRP operation. My own station runs at 5 Watts, since on HF, that's as low as my radio will go. I could go lower by turning down the microphone gain, which interestingly is how some radios actually operate, but for now, 5 Watts seems to be a good starting point and truth be told, even though I've been here for a while, I feel like I'm learning something new every day.

One of the largest challenges associated with using low power on HF is propagation on the HF bands which is more fluid than ever. There's plenty of variables. For example, in addition to the day-night cycle, there's Earth's magnetic field, the impact from coronal mass ejections as well as the solar cycle. As that cycle waxes and wanes, or in my case, wanes and waxes, propagation trends are affected on a longer term basis.

There's all manner of tools to explore this. The Australian Space Weather Service is one of many such bodies that create ionospheric prediction maps showing frequencies and their propagation through the ionosphere. Then there's the derivative ones that use this data to declare if a band is open or closed, spread widely across the globe with little in the way of context, like time, or location.

There are tools like VOACAP which attempt to predict the point-to-point path loss and transceiver coverage dependent on antennas, solar weather and time and date. They also attempt to arrive at a so-called MUF, the Maximum Usable Frequency, defined as the highest frequency at which ionospheric communication is possible for 50% of the days in a month. The LUF, the Lowest Usable Frequency is defined as the frequency at which communication is possible 90% of the days of the month.

All these tools have one thing in common. They're predictions and forecasts. They reflect an attempt at quantifying reality. There is a place for this, but my often repeated encouragement of getting on air to make some noise is advice that covers the gap between prediction and reality.

I've long been a fan of using Weak Signal Propagation Reporter, or WSPR as a tool to measure actual propagation. What I like most about it is that it can be used on your own station, using your own antenna, at any time.

It occurred to me the other day that there must be a relationship between a WSPR signal and a voice signal. Not a mathematical one, but one that makes the difference between establishing a voice contact with another station and calling CQ until you're blue in the face.

With that in mind I took a leap and purchased a ZachTek Desktop WSPR transmitter, capable of operating on all the HF bands that my license permits. It was shipped from Sweden this week and it is expected to take more than a month to get to me, likely most of that travelling between Sydney and Perth, but when it does, I'll be able to set up my own in-house 200 milliwatt beacon that will show me just how far my signal goes on the bands that I pick. As an aside, I'm still looking for a similar solution for 2m and 70cm since there are all manner of interesting propagation phenomena associated with those bands as well.

I'm still digging into how I can best gather the reception data to visualise it and I'm working on a strategy that can send me an alert when a particular band is open from my station at such a level that I can look to operating a particular mode, like FT8, or SSB, or anything that I might choose.

The data is public, thanks to the various WSPR reporting systems around, so others in my grid square, likely beyond that, will also be able to benefit from my beacon. I'm considering generating a propagation map from my own station and publish that, but it's too early to say what's involved in making that happen.

Right now I've dived into the rabbit-hole associated with finding a suitable antenna. My current station vertical requires a tuner and I don't think that finding a way to tune my antenna every time the beacon changes band is a good solution.

I suspect that I'll also need to come up with a way to have two transmitters share the same antenna, but I'll cross that bridge when I need to.

Once the beacon arrives, it's my intention to start with 10m as my beacon band using my current antenna, since 10m is on the verge of being useful for my QRP adventures and I must confess, I'm looking forward to making a voice contact with the other side of the planet with my station for the first time in a long time.

What kinds of things can you think of that would benefit from a solution like this?

I'm Onno VK6FLAB

What have you been up to in Amateur Radio lately ... Gary VK2OVA

Sat, 11/06/2021 - 12:00
Foundations of Amateur Radio

Recently I exchanged emails with fellow amateur Gary VK2OVA. This was his most recent response.

Hello Onno,

What have you been up to in amateur radio lately, you ask hahahahahahaha.

I hope this gives you a good chuckle.

I decided to construct and erect a full wave 80 meter sky loop. Simple antenna, and I have lots of space to do so with an old tennis court on the block surrounded by existing poles and wire mesh.

The preparation for me was the key to having an easy path to a successful outcome. First step was to measure out the existing poles for the best fit, measured, then stood back and looked, then measured again, yes all is good, this will work. Made up the ropes and pulleys, rechecked the length and height, yep all good, put the ropes and pulleys in place, ready to attach the insulators. I'm going for four corners with an overall measure of 23 meters long by 17 meters wide. Using a corner feed point.

Made up a feed point cockatoo deterrent, 90 mil storm water pipe about 15 inches long, split end to end, then zip tied into itself as it wraps around the insulator and feed point. Cockatoos are in abundance here so I had to come up with something to keep them away from the feed point as that seems to be their favourite chew spot.

Purchased a 100 meter long roll of green and yellow earth wire, thinking to myself, easy as, just cut a measured length off the end and have the correct length left on the reel ready to roll out. Oh but wait, a couple of hams talking on air had a similar situation and it worked out that the roll was shorter than quoted on the label. Best practice here is to unroll it and measure it myself, simple task.

Now I cannot find my 30 meter tape measure, so I put the task on hold till it turns up. Two weeks later it is no where to be seen, so now I have decided to go with the 8 meter tape measure. After thinking about how to best measure 8 meters at a time I came up with a marvellous plan, I'll put a couple pegs in the ground at 8 meters apart and simply loop the wire back and forth 11 times. After all, this is 88 meters in total and I can simply trim the length to my chosen frequency of 3.620 MHz. I'm feeling very good right about now as I have saved myself a lot of walking and bending.

Now, the first error pops its little head. After I've cut the wire to length and attempt to lay it out on the ground inside the poles - designated antenna holders - the copper wire reminds me it has a memory. That memory is very adamant, I'm a circle of loops. So yes I now have a birds nest of yellow and green. Have you ever noticed when something like this has a mind of its own, it is, apparently, right. Took at least an hour to unravel it, then several tent pegs, to get this wire to obey me. So I won that battle.

Because I had measured the wire myself I knew it to be accurate, which proved how wrong I was back when I'd completed the original measure, post to post for potential mast poles. So I reset my ropes and pulleys to the new poles and hoisted the whole lot up in the air, then ran inside to view the antenna analyser. Now something is wrong, I cannot get a meter dip anywhere on HF. Oh dear, I've got a break or bad connection.

So into trouble shooting mode goes whats left of my brain. Track and retrace. As much as I did I could not identify what was wrong. Only one thing for it I will go back to the beginning and start over.

Dropped the wire on the ground, pegged it down so it could not get away again. Still could not find my 30 meter tape measure, so out comes the 8 meter tape. But wait, is that a 6 or an 8 on there. Lets settle this, I'll put on my reading glasses just to be sure. Yep it is a 6 meter tape measure, not 8 so therefor I have only got a 66 meter length of wire, oh gosh! Back to square one, move all the pulleys re-measure everything. To correct the problem I had to add on some wire and solder the 2 pieces together. With my new level of cautious approach I managed to get the length perfect at 3.625 MHz.

I still cannot find my 30 meter tape, nor can I find my 8 meter tape, but the good news is I still have a 6 meter tape measure, actually out of six tape measures that I had it's the only one I can find.

I've decided I should probably wear my glasses when reading small print, from now on.

I've been making wire antennas for years and never had an issue. Having just moved here a couple of years ago I'm in a position where size does not impact my antenna choices, hence the ambitious project which took up way to much time and effort.

And, if this is suitable for sharing please do so.

Cheers,

Gary VK2OVA

The only thing remaining is to ask you a question.

What have you been up to in Amateur Radio lately?

I'm Onno VK6FLAB

The Ripple Effects of making change ...

Sat, 10/30/2021 - 12:00
Foundations of Amateur Radio

During the week a new piece of software was born. It's not going to solve world hunger or address man-made climate change, but it will help some contesters who want to get on air and make noise without actually making noise. From my vk6flab github page you can get yourself a copy of a tiny little bash script with the catchy name of ssbdaemon and use it to launch your very own remote-controlled voice-keyer.

After making the announcement I received several emails from excited contesters who wanted to thank me for my efforts and I have to tell you, making something that others find useful is very rewarding.

My announcement also sparked some discussion around using voice-keyers including some who consider that this isn't a useful addition to the hobby.

More on that in a moment.

After the code was written, I had to actually, you know, use it. So I hooked up my radio, launched ssbdaemon and fired up my current contest logger of choice, TLF, and attempted to make noise. Unfortunately I wasn't so lucky as to make it all work on the first try. TLF needs to be in CW mode for ssbdaemon to work and someone, somewhere at some point, decided that when you change band, the mode needs to be set, so despite me setting my radio to either Lower or Upper Side Band, TLF would helpfully change it to CW, which actively prevented me from making noise.

Since TLF is Open Source, I was able to download its source-code and after some trial and error, including discussion with the TLF developer community, I added my own little flavour to my copy of TLF to make it always use sideband. My fix isn't useful long-term, but right now it will make it possible for me to operate my voice-keyer. An alternative would have been to turn off rig control.

This also sparked discussion on the TLF mailing list about how we might implement this kind of functionality long-term. Those two things, the fact that I could hack my own copy of TLF and discuss long-term updates is why I think that Open Source and Amateur Radio are an obvious match.

I released my ssbdaemon script as Open Source too, so I immediately benefited from other people looking at it and giving me feedback. As a direct result my code improved, my tool became more useful and those changes were published for anyone to use, immediately.

At this point I should mention that although I'm using TLF, ssbdaemon is a drop-in replacement for cwdaemon and should work anywhere as a direct replacement, so tools like CQRLOG, Xlog and others can use it with no changes to their code.

Back to the discussion about the usefulness of this tool in relation to our hobby.

I think that a tool like mine does a number of things. It achieves the direct purpose that it was built for, making it possible to create a more universal voice-keyer, but it also does other things.

I set out to make TLF do callsign voice-keying, but in solving the problem, I managed to build a tool that was universal to any station using an external Morse-keyer, regardless of whether or not they were using TLF.

Several emails commented on the way that I'd come to this solution and observed that this opened opportunities beyond my script, including operating Single Side Band contests remotely.

As a direct result of my release there's now a discussion underway in relation to how TLF manages band changes. It's not finished, likely it'll go through several iterations and might not be implemented immediately, but the fact that this discussion is happening comes as a side-effect of my script.

This little script, truthfully almost trivial script, is causing change to happen in unexpected places.

It did make me wonder if there are little things like this that we can do to bring awareness and activity to other areas, things like man-made climate change and how we might achieve that in tiny unexpected ways.

As for running a contest with my new voice-keyer, propagation permitting, keep an ear out and let me know how it goes.

I'm Onno VK6FLAB

How to run an SSB contest without using your voice ...

Sat, 10/23/2021 - 12:00
Foundations of Amateur Radio

As you might know, I consider myself a contester. I derive great pleasure from getting on air and making noise during a contest. It gives me a wonderful opportunity to test my station, hone my skills and work on learning something new every time I participate.

Due to circumstances I've been away from contesting for a number of years, but recently I was able scratch my itch from my own shack. For 24 glorious hours I was able to make contacts from the comfort of my home, being able to make a cup of tea, eat some dinner, stay warm, catch a nap when the bands were closed and generally have a blast.

My set-up worked well. Operating QRP or low power, I used a basic contest logger, since I wasn't expecting to be making many contacts. To automatically call CQ, I recorded my voice and set-up a script that played the audio, waited four seconds, then played it again. Using my audio mixer, I could turn that on and off at will and between that and the headset I was wearing I had loads of fun and even made contacts!

During the last three hours of the contest my partner came home. After hearing me attempt to confirm an exchange for a while, it became apparent that making exchanges, calling CQ and generally talking out loud was going to be an issue in our home, since my shack is within hearing range of the entire house. That or I'm going deaf and my voice is getting louder. I do get excited from time to time!

For the past several months I've been trying to find a solution and until today I wasn't getting any closer.

I didn't think I was asking for too much.

I'm looking for a contest logger, that runs on Linux, that has the super check partial database, knows the contest rules and most importantly, has a voice keyer with the ability to actually voice the exchange itself, as-in, not a pre-recorded audio file, but the ability to speak any callsign and any exchange.

As an aside, the super check partial database is a list of frequently heard contest callsigns, originally introduced by Ken K1EA, which if used properly, helps you when you're deciphering a callsign on a noisy band. Using it to guess calls and make mistakes can result in significant penalties for some contests.

The only tool I've come across that does all this in any way is N1MM. It runs on Windows and I have to tell you, the idea of having to buy a new computer, just to run a supported version of Windows just doesn't do it for me. N1MM also doesn't use Hamlib, so my radio needs to be physically connected to the computer. I won't bore you with my weeks of attempts, but it became farcical.

During my months of exploration I looked at and tried plenty of other tools. Many of them aren't intended for contesting, don't have access to the super check partial database, don't do voice-keying, don't run under Linux, require weird bits of extra software, have little or no documentation and a myriad of other issues like having to compile from source with arcane library requirements, the list goes on.

One contender that got close was a text only tool called TLF. It got so close that I almost used it for my previous contest. In the end I didn't because it was doing unpredictable things with the display and I had to write my own contest rule file for an unsupported contest which I couldn't test in time to actually use.

Today I took another look.

TLF doesn't have a voice-keyer on board, but it does have the ability to interface with a Morse-keyer, which is interesting, since it implies that there is a process that translates callsigns and messages typed in with a keyboard into Morse, which might mean that it may be possible to pretend to be a Morse-key and make voice sounds instead.

The Morse-keyer software in question is cwdaemon. It accepts text messages from TLF and then converts those into Morse code and then directly controls your radio to generate dits and dahs on-air.

I started digging through the source code when I realised that cwdaemon might have a debug mode that shows what it's doing. Turns out, not only does it have a debug option, you can also prevent it from keying your radio. Which means that I should be able to get TLF to generate the messages, cwdaemon to show those messages and me to do something useful, like play audio files as appropriate.

If I pull this off, it will mean that I can operate my station as if I'm running CW, but the radio will be transmitting voice, which makes for a beautiful way to save my vocal chords whilst running a contest without bothering anyone else and do this without needing to install Windows, which frankly, in my book is a win.

If I succeed, and I think the odds are good, I'll publish my efforts on my github repository for you to use, if you're so inclined.

I have to confess, when I started this adventure, I was not at all convinced that I could make this happen and I'd all but thrown in the towel. It still quite unbelievable to me that this kind of thing doesn't appear to exist, but if all goes well, it should soon.

What are you going to be doing for your next contest?

I'm Onno VK6FLAB

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.

Why?

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