The first step in solving any problem is recognising that there is one. In my case the name of that problem is "logging". Specifically the storage and collection of my amateur radio contact logs.

Just to be clear, the actual process of logging is fraught .. what do you log, as in, which pieces of information are germane to the purpose of logging, do you log your own callsign, or do you only collect that once per session, do you log in UTC, or in local time, if you're logging in local time, do you record where you're logging, do you record what power level, which antenna, what radio, the battery voltage, you get the idea.

Then there's .. when do you log? Do you log each and every session on-air, weekly nets, chat sessions on the local repeater, do you log the time when you establish the contact, once you've deciphered their callsign, or once the contact ends, and if you never wear a watch, how do you know what time it is?

What do you log with? Is it using pen and paper, pencil and paper, on a sheet of A4, or A5, in a binder, in a scrapbook, in an exercise book, in a journal, a diary, on ruled, grid or on plain paper, or do you log with a computer and if you do that, using which of the seven gazillion logging packages that are available to you?

I'm not talking about any of those things, though I suppose you could argue that I'm addressing one of the gazillion options, but stick with me.

I have, sitting on my desk, fourteen different logbooks. That's not unreasonable, almost one for each year that I've been licensed. Except that these books are not in any way consistent, they're essentially bound pieces of scrap paper with log entries scribbled in the available space, sometimes I've reversed a spiral notebook, just so I can avoid the spiral with my writing hand, sometimes it's oriented in landscape, other times in portrait. Some are smaller than A5, others are foolscap and intended for accounting purposes.

Next to that pile are too many empty logbooks, intended for future use. Why so many, you ask? Well it goes like this. You go to the office supply store to look for a suitable logbook. You buy it and try it. You use it for a bit and decide that you either love or hate it. If you hate it, you go back to the store to try and find another one. If you love it, your problem becomes finding an identical logbook. In a fit of inspiration, I loved the grid layout of my tiny spiral notebooks, and decided that this was the one for me, but they're no longer available, so instead I bought twenty A4 7mm grid exercise books with a soft cover, which I hate, and that was after trying to get a third Account Book Journal with a hard cover. There's also several A5 spiral bound books, but they're too chunky for portable operation and their spiral is annoying for logging.

There's also various empty ring binders and paper ready for logging in the garage. Who knew that there are apparently multiple disconnected universes where so-called universal loose-leaf hole punched paper doesn't fit ring binders with more than two rings, I suppose that's like different implementations of the same version of ADIF, but I'll admit that I'm bitter and have digressed well off topic. I will say this, stationery and I clearly have an unhealed relationship.

That's not the half of it.

My computer has at least 208 ADIF and Cabrillo files on it. I say "at least", since that's the ones I found when looking for ADI, ADIF and CAB files. Removing identical files, nets me 171 text files which I'm pretty sure are all log files, 50-thousand lines, but that's with some having a one line per contact and others having a dozen, depending on which software wrote the file.

It's going to take a moment, since those 208 files are scattered among 74 different directories. Then there's the files that "wsjt-x" and "fldigi" create, but right now I'm not sure what the extensions for those are, I think one is called "all.txt", and looking inside, it helpfully does not have a year in the logged data, so that's fun. My computer also has logs in "cqrlog", "xlog" and "VKCL", probably others.

Then there's the logs I have online. The log for F-troop is a single spreadsheet, it has nearly 10,000 entries. I know that there's other files online and likely in other places like the various clubs I've operated at .. fortunately or not, most of those were done with the club callsign, so I'm calling those out of scope, at least for now.

Then there's the entries in LoTW, Clublog, eQSL, probably QRZ and likely more.

It all started out so innocently. I made my first contact in 2011 and forgot to log it. Since then I've been extolling the virtues of making sure that everyone around me logs their first contact.

Meanwhile I've been pulling my hair out trying to make sense of the fragmented disaster that is represented by logging in amateur radio. I'll take responsibility for my own mess, but I have to point the finger at my predecessors who still cannot agree on what to log, how to log and how to store or convert it, despite a century of logging.

It's not for the want of trying. It's that the nature of logging in this hobby is less than consistent, to say the least. Each contest wants their log in some special format, logging tools pick their own format that's incompatible with that of another tool, if you're lucky that incompatibility is obvious, but more likely than not it's subtle.

Among all those sources of log entries that I've mentioned are undoubtedly going to be duplicate contacts. There's going to be incorrect transcriptions, inaccurate record keeping, wrong times, missing years and all the other things that come to mind when you describe a data entry problem.

Fortunately I have some experience with data entry.

It was the transcribing of a recent POTA, or Parks On The Air, log that triggered an insight for me. Faced with the reality of entering contacts into something electronic, based on a bound notebook with log entries scribbled all over it, basically a pretty piece of scrap paper, I needed to solve a specific problem. Namely, the fact that I was entering this data for another amateur, who would be uploading it into the relevant POTA system. I had no idea what the field requirements were, didn't know where they'd be uploaded to, nor what format they needed, so I improvised, figuring that getting both the logged and inferred data into some table would be a good start, so I used a spreadsheet.

After completing the task, I had my epiphany.

What if I logged ALL my contacts in a spreadsheet?

I can sort it by whichever column I want, I can have as many columns as I need, a squillion rows if I make that many contacts, I can convert it to whatever format the next contest manager desires and I can back it up like any other spreadsheet. Better still, it's software agnostic. If I suddenly discover the next best logging tool since toasted sliced bread with creamed honey, I can convert my sheet into something that's required. Better yet, I can extract the data from that tool and put it back into the spreadsheet after discovering the author has a propensity of making random changes that are incompatible with my worldview.

So, spreadsheet.

Oh, yeah, I won't be using Excel, it has a, let's call it, nasty habit of converting anything that remotely resembles a date into one, even when you don't want it to. Clippy lives on .. apparently.

I'll likely photograph each page and to keep track of which logs I've entered, I'll put a coloured dot on a page when I've entered it into my spreadsheet. Once a logbook is entered, I'll mark it in some way too. Then I'll have to massage the existing electronic data. I can't wait.

How have you solved your contact logging problem?

I'm Onno VK6FLAB

The other day I was stuck in traffic behind a vehicle proudly proclaiming that it was "electric". I'd seen the model before, just never connected it with being available as an EV. I wondered how many other cars on the road turned out to have added an "electric" option to their line-up and how that evolution had just quietly, inexorably occurred.

It started me thinking about the nature of the driving experience and what it would be like for someone who has never seen a petrol, or other fossil fuel burning vehicle, and what driver education might do to incorporate that.

In my teens I first sat on a hotted up moped belonging to a friend, I was old enough to be legal, whilst he wasn't, so I got to ride his bike to school with him on the back, win-win for both. Later on, I learned to drive a car with a manual gearbox and as interest took me, I learned to drive a double clutch gearbox and got my heavy rigid truck license. I also learned to fly a plane, but that's besides the point.

Stuck in rush-hour traffic, such as it is in Perth, it made me think about amateur radio licensing and education.

Specifically, how do we incorporate change? When I was first licensed, my education included consideration for analogue television interference, including pictures of different screen patterns, their causes and remedies.

Three years after I got licensed, almost to the day, the last analogue television transmitter in Australia was switched off on 10 December 2013, 57 years after the first transmissions started.

While I retain little, if any, of the now, let's call it, esoteric information associated with that, it made me consider a wider picture in relation to the process of amateur radio education.

New amateurs today are unlikely to be asked about analogue television interference, let alone be subjected to questions in their exam. Fair enough, information changes, evolves, becomes superseded or expires, and as a side-effect, I have some brain cells dedicated to analogue television, PAL, 625 lines total, 576 visible, horizontal and vertical synchronisation, white noise, you get the idea. As an aside, 78 on a turntable indicates a speed reserved for shellac records until the 1950s, seeing that we're dropping arcane knowledge. Oh, means NOP on a 6502, in case you're wondering.

Although I don't have a specific list of what is currently being taught .. more on that in a moment .. I daresay that newly minted amateurs have a curriculum that has evolved with technology and legal requirements over the past 15 years.

A tangible example is the fact that the Foundation Class in Australia is now permitted to use digital modes, something that changed after I was licensed, when on 21 September 2019, the regulator amended the Amateur License Conditions Determination, known locally as the LCD, with immediate effect.

The point being that over time things change and education changes with it.

This is all as expected.

Here's my question.

What about the rest of the community? What happens to someone who has been licensed for a decade, a generation, or more?

Are they expected to gain these skills by osmosis or self-education?

Should this process be dictated by the regulator, or should this be a community effort to bring everyone into the same decade?

Should we revise how we educate our amateurs and make the education skill-set technology agnostic, should we be less prescriptive with the license, or should it achieve something else?

One example in this space is an initiative called the Ham Challenge, which you can discover at hamchallenge.org. In case it sounds vaguely familiar, I've talked about this before. It's a list of 52 activities that you can take on to broaden your horizons and explore different aspects of our hobby. In its first year, I'm looking forward to seeing how it evolves.

Is this the kind of self-training that we might encourage, or is there another way to achieve this? Is this something that occurs elsewhere in society and if so, how has that been addressed? I know for example in ICT there are endless certification courses, which I have to confess are in my professional opinion absolutely counterproductive, serving only to entrench vendor lock-in, not something that I think benefits the amateur community.

I mentioned curriculum a moment ago. Another approach is to attend a licensing course and participate as part of your own self-education. Of course this will require cooperation from the educators, and we'd need to come up with some idea of how this might be useful. Is this something that benefits from attendance every five years, every decade, more, less? As a bonus side-effect, it will introduce new amateurs to old ones, and vice versa, perhaps facilitating a new resurgence of Elmering, or mentorship, that previously has been the hallmark of our community.

Over the decade and a half or so that I've been licensed and writing weekly articles about the hobby and our community, I've made a conscious effort to keep up to date, to learn new skills, to share what I've learnt, to actively explore what I need to learn more about and to share that journey with you.

I realise that this is not a universal experience. For some their amateur license sits in a drawer gathering dust together with their first aid certificate and their first runner-up prize for something that for a minute and a half caught their attention years ago.

For most of us the reality lies somewhere in between. For many, the amateur experience is one of playing on air and getting delight from the doing and participating.

There are those who go out and become teachers, those who sit on boards, those who run clubs and those who get on the local repeater once a week. It takes all of us to make this community and my thoughts are not intended to stop that enjoyment and experience.

I'm trying to discover how we build a resilient community, one that is sustainable in a world of continuous and rapid change.

I'm Onno VK6FLAB

Recently I spent some quality time digging into the origins of a word in common use. In doing so, I contacted the Postal Museum in the United Kingdom and received a lovely reply that included a photo of a document in their archive.

The document, a Post Office Circular from Friday, December 30, 1904, number 1641, introduces a new service offered by the Post Office.

Let me read to you what it says, and I quote:

"Telegrams to and from Ships by Wireless Telegraphy.

"(To be noted at Telegraph Offices only.)

"With the present Circular is enclosed a list showing the wireless telegraph stations in the United Kingdom worked on the Marconi Company's system, and the hours up to which telegrams can be received at those stations for transmission by wireless telegraphy to certain ships fitted with Marconi apparatus. By another notice in this Circular, Postmasters and others concerned are requested to enter the names of the stations in the Code Book with the necessary particulars. Ships will be issued for insertion in the Post Office Guide.

"On and from the 1st January, 1905, Telegrams may be accepted from the public on the following conditions:-

"Subject to the Inland Regulations with regard to counting, the charge, which must be prepaid in the usual way by means of stamps, will be at the rate of 6 1/2d. [six-and-a-half pence] a word, with a minimum of 6s. 6d. [six-and-a-half shillings] per telegram.

"The name of the wireless station will in each case pass as one word in the address.

"The word 'Radio,' which is not charged for, should be telegraphed in the Service Instructions."

When I read that, it made the hair stand up on the back of my neck. The introduction of a Wireless Telegram service, under the service heading of "Radio", with a photo of the actual document that introduced it into the world.

I also learned that there's a dozen pennies in a shilling and over the years before decimalisation in 1971, the composition of coins changed, which made converting this into today's money interesting. As an aside, the Royal Society has a wonderful article: "The science of money: Isaac Newton's mastering of the Mint"

Back to radio, this is 1904 bleeding edge technology and it's priced accordingly. The starting price for a radio telegram on new years day 1905: six bob and six; or three florin and sixpence; or a crown, a bob and a tanner; is worth just over 34 Great British Pounds today, that's just on 45 US Dollars, or nearly 69 Australian Dollars. That's the minimum price.

The price per word, sixpence and halfpenny [sixpence hayp-ny] is just over 2 Great British Pounds today, nearly 4 US Dollars or almost 6 Australian Dollars.

Compare that to the price of SMS, which started at about 21 cents here in Australia, today it's about 3 cents per message of 160 characters.

This seems like a lucrative business to be in, but I digress, again.

From my current, and ongoing research, it appears that until this point, the early 1900's, the word "radio" was always accompanied by another word, for example in this context, "radio telegraphy", another combination of the day is "radio active", as well as "radio tellurium", which today we know as polonium.

Moving on, the response I received from the Postal Museum included other gems, including a reference to the "1904 Wireless Telegraphy Act", from the 15th of August, 1904, where I found something fascinating, from Section 2 paragraph 1:

"Where the applicant for a licence proves to the satisfaction of the Postmaster-General that the sole object of obtaining the license is to enable him to conduct experiments in wireless telegraphy, a license for that purpose shall be granted, subject to such special terms, conditions and restrictions as the Postmaster-General may think proper, but shall not be subject to any rent or royalty."

I think that's the birth of amateur radio licensing in the United Kingdom, right there.

As an aside, because I cannot help myself, the definition for the expression "wireless telegraphy", is pretty interesting too, reminding me of a quote, variations going back to at least 1866, incorrectly attributed to Einstein that goes something like this:

You see, wire telegraph is a kind of very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, and they receive them there. The only difference is that there is no cat.

Seems that the drafters of the "1904 Wireless Telegraphy Act" had the same thing in mind when they wrote:

"The expression 'wireless telegraphy' means any system of communication by telegraph as defined in the Telegraph Acts, 1863 to 1904, without the aid of any wire connecting the points from and at which the messages or other communications are sent and received"

Now, as I said, I'm still working on this, because the word "radio" as a concept had to have been conceived before the Post Office Circular was written, printed and published. It might transpire that this was the brainchild of a single individual, or it might be that this was a term whose time had arrived, or this might not be the first occurrence of the word "radio" as a concept.

Today we think nothing of it when we use it to turn on the radio, listen to, or talk on the radio, radio for help, break radio silence, and plenty of other uses of this now ubiquitous word.

Thanks again to the Postal Museum for finding and photographing the Post Office Circular for the 30th of December 1904, which at this stage appears to be the first occurrence of the word "radio" on its own, and for referring me to the 1904 Wireless Telegraphy act which appears to be the birth of "amateur radio" in the United Kingdom.

You can find both documents on my project site at vk6flab.com.

I should also mention the brave individuals who took the time to share with me how to refer to Old British Money, any mistakes are all mine.

I'm Onno VK6FLAB

I know that "s." refers to "shillings" and "d." to "pennies", and I believe that "6d." is "sixpence".

Anyone?

If you have a source, all the better!

Edit: Thank you all for your amazing assistance. Here's what it was for.

https://lemmy.radio/post/10377731

If you use a word often enough it starts to lose its meaning. The other day, during breakfast, well, coffee, whilst playing one of our start-the-day with a smile word games, the word "RADIO" turned up. I grinned and pointed out that this was my favourite word, to which my partner mentioned that in Italian, it's referred to as "La Radio", which made us both wonder where it actually came from, did the Italian language import the word, or export it, given that Guglielmo Marconi was Italian?

A quick search advised us that it came from Latin, radius, meaning "spoke of a wheel", "beam of light" or "ray".

Fully enlightened we finished our coffee and got on with our day .. except I couldn't stop thinking about this.

Having recently spent some quality time looking into the history of the RF Circulator, I figured searching the patent records might be a solid way to get some handle on where this word "radio" came from.

Initially Google Patent search unearths the oldest as being from 1996, not very helpful. Adding 1900 as the end date filter turns up a radio cabinet patent with a filing date of 1833, except that it was published and granted in 1931, which is confirmed by the patent itself.

This level of corruption in the data affects at least a dozen patents, but I daresay that there's plenty more like that.

1857 turns up a patent with the word "broadcasting", in the context of "broadcasting guano", so, nothing much has changed in nearly 170 years, but I digress.

Adding quotes to the search term unearths a patent from 1861, apparently iron roads, locomotives, large slopes and small radio curves relates to the other meaning of the word radius, in Spanish.

1863 gives us ruffle stitching, "made upon the radio", but the patent is so corrupt that it's pretty much unreadable.

1871 unearths an electromagnetic engine, but the text has so much gibberish that I suspect that the word "radio" is a happy accident.

1873 shows us a "Wireless signalling system", bingo, the patent shows us transmitter and receiver circuits, antennas, messages and frequencies and a whole bunch of relevant radio information, except that the date on the patent itself is 1919.

And you wonder why people argue about who invented what when?

I'll spare you the gas apparatus, petrol lamps with cigar cutter, running gear for vehicles and bounce to 1897, "Method of and apparatus for converting x-rays into light for photographic purposes", the first occurrence of "radio", in the form of "radiograph", complete with pictures of the bones of a hand drawn meticulously from presumably an x-ray.

I confess I'm not convinced.

Using the United States Patent and Trademark Office search for the word radio gives you 54,688 pages with 2.7 million records, ordered in reverse chronological order with no way to skip to the last page.

The World Intellectual Property Organisation finds the same Spanish iron paths patents, but unearths "A Differential Arrangement for Radio Controlled Race Cars" from 1900, but inside we discover it's really from 1979.

Seems this level of corruption is endemic in the patent field, wonder who's benefiting from this misinformation?

Meanwhile, still looking, I discovered the Oxford English Dictionary, which claims that the earliest known use of the word "radio" is in the 1900's, but the earliest evidence is from 1907 in a writing by "L. De Forest", but you are granted the privilege of paying them to actually see that evidence .. really?

On 18 July 1907, Lee de Forest, made the first ship-to-shore transmissions by radiotelephone, which adds some credence to the claim, but I have to tell you, I'm not particularly convinced.

Taking a different approach, starting at Guglielmo Marconi, his first efforts in 1894 showed the wireless activation of a bell on the other side of the room. Six months later he managed to cross 3 kilometres realising that this could become capable of longer distances. The Italian Ministry of Post and Telegraphs didn't respond to his application for funding, so in 1896, at the age of 21, moving to Great Britain, he arrived in Dover where the customs officer opened his case to find various apparatus, which were destroyed because they could be a bomb.

Lodging a patent "Improvements in Transmitting Electrical impulses and Signals, and in Apparatus therefor", was the first patent for a communication system on radio waves. It was granted a year later.

One problem.

It doesn't have the word "radio" in it, instead it talks about "a Hertz radiator", so close.

So, we've narrowed it down to somewhere between 1896 and 1907, that's an 11 year window.

Some observations.

De Forest founded a company called "the Radio Telephone And Telegraph Company". It's unclear exactly when this happened, it collapsed in 1909 and was founded after disagreement with management of his previous company, apparently on 28 November 1906.

A quick aside, apparently in 1881, Alexander Graham Bell used the word radiophone for the first time, which he used to refer to a system that used light to transmit wirelessly, he also referred to it as a photophone.

You could argue that because light and radio are the same thing, this is the first legitimate use of the word "radio" in the context of communication, but I'm not buying it.

I'll leave you with the discovery that on 30 December 1904, the British Post Office published a "Post Office Circular" with the instructions to use the word "Radio" in the service instructions, think of it as the metadata associated with a telegram. This information has been repeated often without evidence.

If you're keen, the Postal Museum is located in Phoenix Place, London. I've contacted them to see if that particular Circular is in their possession.

Amazingly the "Post Office Circulars" have been digitised between 1666 and 1899. So close, but no cigar, that said, I looked for the elusive Volume 7 of the set to see if there were any straggling references to "radio", but couldn't confirm this.

The Postal Museum Catalogue returns plenty of early references to radio, but it's hard to tell what's real and what's written after the fact. Anyone know of any research grants that will allow me to dig into this on-site, feel free to get in touch, oh, a bed would be good too .. I think this might take a while.

At the moment, the best I have is an uncorroborated "30 December 1904" for the origin of the word "Radio", in English, in other words, it was imported into Italian. No sign of Marconi, Bell, or De Forest.

I'm Onno VK6FLAB

Recently I explored the use of a radio device aptly described by a fellow Aussie Electronics Engineer, "ozeng", as "Absolute witchcraft." .. I'm talking about an "RF circulator", one of which is sitting quietly on my desk, roughly 60 mm square, 30 mm thick, weighing in at just under half a kilogram, unexpectedly with a 200 year history.

Let the spelunking commence ..

The moment you start reading the "Circulator" Wikipedia page, you'll see this sentence: "Microwave circulators rely on the anisotropic and non-reciprocal properties of magnetised microwave ferrite material.", with a helpful reference to "Modern Ferrites, Volume 2: Emerging Technologies and Applications", a 416 page reference that promises to dig into the nitty-gritty, showing 55 hits for the word "circulator".

Anisotropic you ask? It's the property that describes velvet, rub it one way, it's smooth, rub it the other way and the hair stands up on the back of your neck. Wood is another example, easier to split along the grain than across it.

While we're at it, reciprocity in physics is the principle that you can swap the input and output of a linear system and get the same result.

If you know me at all, it should come as no surprise that I went looking for an inventor. There's over twelve-thousand patents referring to a "circulator", including more than a handful relating to Nuclear reactors. In 1960, a prolific Jessie L Butler came up with patent US3255450A, "Multiple beam antenna system employing multiple directional couplers in the leadin", which states: "This circulator has the characteristic that energy into one port will leave another port to the exclusion of a third."

If you recall, that's the exact phenomenon I used to describe the "RF circulator" on my desk.

So, job done, we have our inventor. Not so fast. The patent goes on to say: "Circulators of this type are discussed in an article 'The Elements of Nonreciprocal Microwave Devices' by C.Lester Hogan in Volume 44, October 1956, issue of Proceedings of the IRE, pages 1345 to 1368." The IRE is the Institute of Radio Engineers.

I found a copy of that tome, thank you worldradiohistory.com, which includes the following sentence: "Until a few years ago, all known linear passive electrical networks obeyed the theorem of reciprocity. Today several different types of passive nonreciprocal microwave networks are in practical use".

A footnote refers to an article by Lord Rayleigh, "On the magnetic rotation of light and the second law of thermodynamics" and includes images of an optical one-way transmission system from 1901.

In that 1901 article, Lord Rayleigh in turn refers to a paper published sixteen years earlier in which he observed that light polarisation can be made to violate the general optical law of reciprocity, using a system that consists of two so-called Nicol prisms, a crystal that can convert ordinary light into plane polarised light, invented by William Nicol in 1828. Using two prisms, arranged at a 45 degree angle, you can make light go through it in one way, but not the other.

Lord Rayleigh, also known as John William Strutt, in a very sparse footnote, states: "That magnetic rotation may interfere with the law of reciprocity had already been suggested by Helmholtz."

Further digging gets me to an 1856 publication of the "Handbuch der physiologischen Optik", or the handbook of the study of how the eye and brain work together, where Helmholtz says that, translated from German, "according to Faraday's discovery, magnetism affects the position of the plane of polarization."

This gets us to 1845, where Michael Faraday experimentally discovered that light and electromagnetism are related. His notebook has the following sentence, paragraph 7718 written on the 30th of September 1845: "Still, I have at last succeeded in illuminating a magnetic curve or line of force and in magnetising a ray of light."

Today we call that the "Faraday effect"

The best part?

You can read Michael Faraday's diary, right now, and see the whole thing.

So, who then invented the RF circulator?

From Mastodon to Circulators, to Modern Ferrites, to Nonreciprocal Microwave Devices, to Multiple beam antennas, to Magnetic Rotation, to Optical Reciprocity, to Nicol prisms, to the Faraday effect, this is the perfect example of standing on the shoulders of giants, and the result sits as a little box on my desk.

Just so you don't feel left out, your mobile phone likely has one of these devices on board.

I'm Onno VK6FLAB

The other day I saw a post by fellow amateur Gary N8DMT who mentioned an "RF circulator" and a PlutoSDR in the same sentence. Amplified by a response from a fellow Aussie Electronics Engineer, "ozeng", who helpfully added a link to a Wikipedia article about circulators, it finally twigged that I had such a gadget in my possession and for the first time I realised how I might use it.

Now, before I continue, I'll preface this with a disclaimer, this is a hand-wavy description of what this very interesting device does. "ozeng" calls it "Absolute witchcraft." and that's an apt description if ever I've heard one.

Imagine for a moment a radio with separate transmitter and receiver connectors, attached to the same antenna using a T-piece, as-in, there's a run of coax coming from each connector, joined together with a T-piece, which in turn is connected to an antenna.

The aim of this, don't do this at home contraption, is to avoid the need for two antennas, but, and it's a big one, doing this will very likely destroy your receiver the moment you transmit for the first time, because likely half the transmission will go to the antenna, while the other half makes its way to the receiver, which is not going to be something you want to happen, unless you like the smell of magic smoke.

You might think that adding an attenuator, something that reduces the power on the receive port would help. Well, yes, it would, but as a side-effect, it would also reduce the signal coming from the antenna.

At that point you'll decide you need a switch. Initially you might switch this manually, but that's a pain if you're wanting to transmit and receive continuously and need to remember in which position the switch is in.

The next step is to use an electronic switch, like a relay. It can trigger based on some signal from the radio when it's transmitting and turn off the receive path during a transmission.

This raises an issue with delay. Do you trigger just before you hit the PTT, as-in, time-travel, or do you delay the transmitter until after the relay has switched, which will cut off the beginning of your transmission?

You'll likely have heard this kind of issue when listening to a station using an external amplifier. Their signal either jumps from low power to high power after they key up, or you miss the beginning of their callsign.

Not to mention that if you get the delay wrong, you blow up the receiver, fun for people watching, not so much for the equipment owner. Even if you get the timing right, you cannot transmit and receive at the same time.

Of course an obvious solution is to have two antennas, but soon you'll discover that when you're transmitting and receiving on the same frequency, even using two antennas, you'll have the exact same issues. It's why the local 10m repeater here in Perth, VK6RHF, has the transmitter in one location and a receiver 12 km away, connected to each other via a 70cm radio link.

Other solutions in this space are cavity filters, duplexers and diplexers. These all require that the transmit and receive frequencies are different and the equipment is generally tuned to a specific pair of frequencies. Physically cavity filters can be massive, not to mention fragile.

So, solving the issue of having a transmitter and receiver together on the same frequency is one that is challenging to say the least.

It's a common issue, think about mobile phones, satellites, broadcast transmitters, and even your own amateur radio station.

An RF circulator is a device that solves this in an extremely elegant way. For starters, it's a passive device, which means that you don't need to power it, there's no moving parts, no switches, no delays, no external controls, it's a box, generally with three sockets or ports, though versions exist with more.

At a basic level, it works like this. A signal inserted into port one, will only come out of port two. Similarly, a signal into port two, will only come out of port three and finally, a signal into port three, will only come out of port one.

Think of it as a one way roundabout.

How is this useful you might ask.

I'll illustrate by plugging in three things, connect port one to an antenna, port two to a receiver and port three, a transmitter.

When you transmit into port three, the signal only goes to the antenna, leaving the receiver safe and happy. Similarly, any antenna signal will only go to the receiver.

So, how does this work? Remember, hand-wavy.

Essentially, it's based on the idea that radio waves travelling in one direction combine and waves travelling in the opposite direction cancel. Different types of circulators achieve this in different ways and come in different sizes as a result. The RF circulator I have is roughly 60 mm square, 30 mm thick, weighing in at most of half a kilogram and as far as I know, intended for operation around 850 MHz. If I recall correctly, it came out of a CDMA mobile phone tower.

The parameters that describe an RF circulator are the frequency range, the insertion loss, or how much signal gets lost getting from port one to port two, the isolation, or how much signal leaks between port one and port three and a couple of others. Hopefully I'll be able to use a NanoVNA, or PlutoSDR to get a sense of what these values are and confirm the frequency range.

Now, if that doesn't blow your mind, wait until I tell you about the two hundred year history that accompanies it.

I'm Onno VK6FLAB

As a regular contributor to discussion across a wide spectrum of Lemmy (and other fediverse) communities, I've come to see some people who will submit a post, get replies and then delete that post.

While I understand that this is a feature of the platform, in my opinion, it's extremely disrespectful to anyone who took the time to provide a considered, or otherwise, response.

While we're building a global community, is there any appetite to discourage such behaviour, or are we okay with this experience?

One idea might be to update the platform to "zombie" a post when its author deletes it, leaving it exactly where it is, but removing the author.

Anyone?

The other day I received an email from Frank K4FMH asking me about an idea I'd worked on some time ago, namely the notion that I might monitor solar flux at home using a software defined radio. At the time I was attempting to get some software running on my PlutoSDR and got nowhere fast.

Before I continue, a PlutoSDR, or more formally an ADALM Pluto Active Learning Module by Analog Devices, is both a computer and a software defined radio receiver and transmitter in a cute little blue box. I've talked about this device before. It's an open design, which means that both the software and hardware are documented and available straight from the manufacturer. Out of the box it covers 325 MHz to 3.8 GHz. You can connect to a PlutoSDR using USB or via the network, wireless or Ethernet, though I will mention that neither of those last two is currently working for me, but more on that later.

Encouraged by Frank's email, I set out to explore further and came across a 2019 European GNU Radio days workshop, which discussed some of the tools that are available for the PlutoSDR, accompanied by two PDF documents walking you through the experience.

One comment around why the PlutoSDR uses networking as one of the connectivity options spoke to me. From a usability perspective, networking makes it easier to access the PlutoSDR from a virtual machine, since most of the time that already has network connectivity, whereas USB often requires drivers.

As you might recall, network connectivity is one of the many things that I'm trying to achieve with a project that I'm calling Bald Yak, since by the time we're done, there's not going to be much hair left from all the Yak Shaving. The Bald Yak project aims to create a modular, bidirectional and distributed signal processing and control system that leverages GNU Radio.

As a result, I set about trying to actually walk myself through those PDF tutorials .. and got stuck on the first sentence on the first page, which helpfully states: "The necessary prerequisites have been installed on the local lab machine."

It went on to supply a link to a page with instructions on how to acquire those very same prerequisites. Two days later, after much trial and error, I can now report that I too have these installed and because I cannot help myself, I made it into a Docker container and published this on my VK6FLAB GitHub page. To put it mildly, there's a few moving parts and plenty of gotchas.

As an aside, if you think that installing Docker is harder than installing these tools, I have some news for you .. trust me .. by a long shot .. it's not.

Right now I'm working on writing the documentation that accompanies this project such that you can actually use it without needing to bang your head against the desk in frustration. Mind you, the documentation part of this is non-trivial. For reasons I don't yet understand, my Pluto does not want to talk to the network directly over either WiFi or Ethernet, and connecting over USB through a virtual machine inside a Docker container is giving me headaches, so right now I'm connected across the network to a Raspberry Pi that's physically connected to the Pluto.

As a result, I can now use the tools inside my Docker container, connected to the Pluto through the Pi and if you're curious, 'iiod' is the tool to make that happen .. more documentation.

At this point you might well ask, why bother?

This is a fair question. Let me see if I can give you an answer that will satisfy.

Monitoring solar flux typically occurs at 2.8 GHz, which is outside the range of RTL-SDR dongles which top out at about 1.7 GHz. For the PlutoSDR however, it's almost perfectly within the standard frequency range.

One of the tools that is introduced by the talk is an application called 'iio-scope', which as the name suggests, is an oscilloscope for 'iio' or Industrial I/O devices, of which the PlutoSDR is one. As an aside, the accelerometer in your laptop, the battery voltage, the CPU temperatures, fans, and plenty of others, are all 'iio' devices that you can look at with various tools.

So, once I've finished the tutorials, I suspect that I will understand a little better how some of the various parts of the PlutoSDR hang together, and I can set it up to monitor 2.8 GHz.

Of course, that's only step one, the next step is to make a Raspberry Pi record the power levels over time, better still, record it on the PlutoSDR itself, and see if we can actually notice any change .. without requiring anything fancy like a special antenna, some massive filters, a special mount and all the other fun and games that no doubt will reveal themselves in good time.

It also means that, if I got this right, I have the beginnings of the bits needed to get the PlutoSDR to talk to GNU Radio.

Why?

Because I can, and because Frank asked, also Yak Shaving.

I'm Onno VK6FLAB

Build a Docker container for PlutoSDR

This project provides a Dockerfile that builds (and runs) the binaries used for the various tools that connect to the ADALM PlutoSDR. Much of this code is gathered from various sources and some library dependencies are duplicated as a result.