[continued from previous message]

This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20210321.foundations-of-amateur-radio.mp3

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Making observations

Posted: 13 Mar 2021 08:00 AM PST


Foundations of Amateur Radio


Amateur radio is an environment for infinite possibilities. I've spoken
about the way that contacts can happen, seemingly out of the blue, how propagation has so many variables it's hard to predict what will happen at
any given moment. During a contest you might scan up and down the bands
looking for an elusive multiplier, a contact that's worth extra points, or
a missing DXCC country, in your quest to contact a hundred or more. It's
easy to get swept away in the excitement and disappointment that comes with success and failure.


I'm mentioning this because it's pretty much how many people in our
community go about their hobby, me included.


I've likened making a contact to fishing, taking your time to get the
rhythm of the other station, understanding that there's a human at the
other end. Taking stock of what they're hearing, which stations they're responding to, how they respond and if they give out hints about making a successful contact with them.


The other day I came across a request to decode some Morse on an image
showing long and short lines joined together in some form to serve an
artistic purpose. Others pointed out that this wasn't Morse. I took an
extra moment to point out that Morse had four individual attributes. It has
a dit, a dah, a spacing between the letters and a spacing between the
words, and since this image didn't have that it couldn't be Morse code. A
few days later it occurred to me that I hadn't been paying attention. Morse actually has five attributes, it also has a spacing between each tone. I updated my answer and began to think about this interaction.


It's not the first time that I've stopped to consider what's happening.


For example, if I change bands on FT8, a digital mode that is very helpful
for determining current propagation, I have a look at the level of
activity. I'm generally not in a hurry, so I tend to leave it on the same
band for a while, sometimes an hour, sometimes less, sometimes more. If the band is in full flight with every slot filled, it's easy to tick the "CQ
Only" box and hide all the noise, or rather extra messages that form the exchange, but sometimes that noise has a whole lot of interesting
information.


You can determine if one of the stations calling CQ is actually answering anyone or if they're just an alligator, all mouth, no ears. You can see individual people attempting to get each other's attention, making a local
or a long distance contact. You can type in an interesting grid locator
that accompanies most CQ calls and see just how far it is from you and in
which direction.


I will also point out that using FT8 to observe a so-called dead band can
be just as illustrative. It allows you to see signals in the waterfall, it decodes things that are barely visible and it will give you a feel for how
your station at that location on that band at that time is performing in real-time. For example, it showed me that the squelch on my radio was
turned on and blocking any chance of receiving weak signals, something that
I wouldn't have noticed if I hadn't taken the time to observe.


Another example. During a contest I often take some time to listen to a
pile-up that surrounds a massive station to see what stations I can hear,
who is coming in strong and who is coming in weak. I keep a mental or
actual note of what cracks the S-meter with an indication of signal
strength and what only turns up as audio, perfectly readable, but not
exciting the needle in any way. I might not speak with any of those
stations, but I know that there are stations in a particular location that
I can hear.


It's easy to get swept up in all this massive excitement that is our hobby,
but sometimes it pays off to take a breath, to wait a moment, to take a
look and have a listen to learn the lay of the land and understand what is happening and consider the implications. Within that moment of calm you
might find an unexpected jewel in the rough. That's for example how I
managed a contact with South Sudan several years ago during a massive
pile-up in a club station during a contest.


I'd love to hear what you have stumbled upon serendipitously like that. You
can always get in touch, cq@vk6flab.com is my address.


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20210314.foundations-of-amateur-radio.mp3

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Word of the day: software

Posted: 06 Mar 2021 08:00 AM PST


Foundations of Amateur Radio


Every community has its own language. As a member of that community you
learn the words, their meaning and their appropriate use. For example, the combination of words "Single Side Band" have a specific meaning inside
amateur radio. Outside of radio, those same words are random words with no relationship.


Sometimes a term like "FM" can be heard across many communities with
similar understanding, though not identical.


It gets tricky when a word is used widely but doesn't have a common understanding at all. A word like "software" for example.


A question you might hear in amateur radio is: "Can I buy a software
defined radio or SDR that has digital modes built-in?"


It's a perfectly reasonable question, the radio runs software, the digital modes are software, so the answer is obvious, right?


What about: "Can the hundred or more computers in my car play Solitaire?"


Aside from the perhaps unexpected fact that your car has computers on
board, you most likely know the answer to that. No, since the computers are specialised for different tasks - and if you're driving a Tesla right now,
yes, you can play Solitaire, but I'd recommend that you keep your eyes on
the road instead.


My point is that not all software is created equal.


The software inside an SDR is essentially doing signal processing, often by several components, each running software, transforming an antenna signal
into something, that can be used somewhere else, likely sound.


The applications WSJT-X and fldigi, both software, use a computer running Linux, MacOS or Windows, software, to decode and encode digital modes while providing a way for you to interact with it. Software running on software.


You might well argue that we should be running applications like that
directly on our radio and on the face of it that sounds perfectly
reasonable, except that to achieve that, you'd also need to build a system
to install and update different types of applications, so you could run
SSTV, APRS, RTTY, PSK31, FT8 or any of the other hundreds of digital modes
and new ones as they are developed.


If you did that, you'd also have to provide a way to manage the operating system, to connect to the Internet and provide security. You'd need to
develop a user-interface, perhaps a keyboard and mouse solution, a screen,
etc.


Before long you'll have developed a whole computing infrastructure, much
like the one we already have in the form of the computer on your desk or
the phone in your pocket.


Computers are getting faster and faster every day. This allows for the
software on them to become more and more complex. The inter-dependencies
are increasing by the second, but that doesn't mean that specialisation
isn't useful.


A software defined radio likely has a Field Programmable Gate Array, an
FPGA on-board that is great at processing data in streams. It too runs software. Your microwave is running software, as is your television, your smart-watch, your battery charger, the gearbox in your car and your
electric tooth brush.


Making a distinction between the various types of software is helpful to understand what is possible and what is not. Being a computer nerd, I must point out that I've only barely scratched the surface of software here,
in-case you're curious, microcode, firmware, hardware abstraction, the
rabbit hole goes very deep.


Not all software is created equal and every now and then it's a good idea
to remember that when you talk about a word in one community, it might mean
a completely different thing in another and sometimes the distinction is significant.


As for having an SDR that runs WSPR, no. You can transmit from a computer though, but that's a whole other thing.


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20210307.foundations-of-amateur-radio.mp3

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How many hops in a jump?

Posted: 27 Feb 2021 08:00 AM PST


Foundations of Amateur Radio


Amateur radio lives and dies with the ionosphere. It's drilled into you
when you get your license, it's talked about endlessly, the sun impacts on
it, life is bad when the solar cycle is low and great when it's not.
There's sun spots, solar K and A indices, flux, different ionosperic bands
and tools online that help you predict what's possible and how likely it is depending on the time of day, the frequency, your location and the curent
state of the sun. If that's not enough, the geomagnetic field splits a
radio wave in the ionosphere into two separate components, ordinary and extraordinary waves.


All that complexity aside, there's at least one thing we can all agree on.
A radio wave can travel from your station, bounce off the ionosphere, come
back to earth and do it again. This is known as a hop or a skip. If
conditions are right, you can hop all the way around the globe.


I wanted to know how big a hop might be. If you know that it's a certain distance, then you can figure out if you can talk to a particular station
or not, because the hop might be on the earth, or it might be in the ionosphere. Simple enough right?


My initial research unearthed the idea that a hop was 4000 km. So, if you
were attempting to talk to a station at 2000 km or at 6000 km you couldn't
do that with a hop of 4000 km.


If you've been on HF, we both know that's not the case.


If you need proof, which you really should be asking for, you should check
out what the propagation looks like for any FT8 station, or any WSPR beacon over time and you'll notice that it's not 4000 km.


Just like the crazy network of interacting parameters associated with propagation, the distance of a hop can vary, not a little, but a lot.


In 1962, in the Journal of Geophysical Research D.B. Muldrew and R.G.
Maliphant contributed an article titled: "Long-Distance One-Hop Ionospheric Radio-Wave Propagation". They found that in temperate regions such a hop
might be 7500 km and in equatorial regions even 10,000 km.


I'm mentioning this because this was based on observations and measurements.


They used frequency sweeps from 2 to 49 MHz though they called them Mega Cycles, using 100 kHz per second, that is, over the duration of a second,
the frequency changed by 100 kHz, so each sweep took nearly 8 minutes using only 15 kilowatts, so substantial gear, not to mention expense and availability.


Oh, computers, yes, they used those too. A three tonne behemoth called an
IBM 650, mind you, that's only the base unit, consisting of a card reader, power supply and a console holding a magnetic drum unit.


You know I'm going somewhere with this right?


Today, you can do the same measurements with a $5 computer and a $20
receiver. For a transmitter, any HF capable radio will do the trick, though
you might not be transmitting long if you stray outside the amateur bands.
For power, 5 Watts is plenty to get the job done.


My point is that there is a debate around the future of our hobby and why
modes like FT8 are such a controversial topic in some communities.


I'm here to point out that since that publication in 1962 our hobby has
made some progress and we can improve on the work done by people who came before us. We could build a glob-spanning real-time propagation
visualisation tool, we already have the data and modes like FT8 keep
feeding in more.


If you're inclined, you could even make such a plot in real-time for your
own station.


So, how long is a hop?


You'll just have to find out.


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20210228.foundations-of-amateur-radio.mp3

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You Can't Always Get What You Want

Posted: 20 Feb 2021 08:00 AM PST


Foundations of Amateur Radio


One of the things about amateur radio that I find intensely fascinating and
to be honest sometimes just as frustrating, is that you don't know what the outcome of an experiment might be at any one time. Not because you cannot control the experiment, or because you don't know what you're doing, but because the number of variables involved in most meaningful amateur radio experiments is pretty much infinite.


I've spoken about this before, the idea that if you were to make a simple dipole antenna and fold the ends on each other, you'd have infinite
variation in antennas with just a so-called simple antenna, since you can
vary the shape of it in an unending variety of ways.


The other day I was doing an experiment. An amateur radio one to be sure,
but I was doing this within the realm of computing. I have been playing
with digital modes for some time now and along the way shared some of what
I've learnt. It occurred to me that I've been assuming that if you had the chance to follow along, you'd have access to the required hardware, simple enough, a $20 RTL-SDR dongle, but none-the-less, extra hardware.


What might happen if you rule out that dongle and instead used a web-based receiver like WebSDR, or KiwiSDR, or any number of other such sites where
you can pretty much tune to any band and frequency and see what's going on
at a particular antenna location.


For one it might allow you to decode something like APRS remotely, or
decode an FT8 signal, perhaps even your own FT8 signal. Unfortunately most,
if not all, of those sites include only the bare bones decoders for things
like CW, AM, SSB and FM. After that you're pretty much on your own.


You could do some funky stuff with a web-browser, linking it via some
mechanism to the tool you use to actually decode the sound and there's some examples of that around, none that I really warmed to, since it requires
that I open a web browser, do the mouse-clicky thing and then set-up some
audio processing stuff.


What if I wanted to figure out where the ISS was right now and wanted to
listen to a receiver that was within the reception range of the ISS as it passed overhead, and automatically updated the receiver in real time as the
ISS was orbiting the earth?


For that to happen you'd need something like a command-line tool that could connect to something like a KiwiSDR, tune to the right frequency and
extract the raw data that you could then decode with something appropriate.


Turns out that I'm not the first person to think of this. There's even a project that outlines the idea of following a satellite, but it hasn't
moved anywhere.


There's also a project that is a command-line client for web-based KiwiSDR sites, but after spending some quality time with it and its 25 clones on github, I'm not yet at the point where this will work. Mainly because the original author made a design decision to record data to a file with a
specific name and any clone I've found thus far only allows you to define
what name to use. None so far actually appear to send their stream to
something that can be processed in real time.


Of course I could record a few minutes of data and process that, but then
I'd have to deal with overlap, missing data, data that spans two files and
a whole host of other issues, getting me further and further away of what I
was trying to do, make a simple web-based audio stream digital mode decoder.


As the Rolling Stones put it, "You Can't Always Get What You Want"


And to me this sums up our hobby in a nutshell. When you call CQ, or go portable, or test an antenna, or attempt to build something new, there's
going to be setbacks and unexpected hurdles.


I think that it is important to remember that amateur radio isn't finished, it's not turn-key, no matter how much that appeals, you cannot find a one
size fits all solution for anything, not now, not yesterday and not
tomorrow.


This hobby is always going to test boundaries, not only of physics, but
your boundaries. It's after all one giant experiment.


So, next time you don't get what you want, you might try something you
find, and get what you need.


Also, apologies to Keith Richards and Mick Jagger for butchering their
words, a rockstar I am not.


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20210221.foundations-of-amateur-radio.mp3

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Running out of things to do ...

Posted: 13 Feb 2021 08:00 AM PST


Foundations of Amateur Radio


So, there's nothing on TV, the bands are dead, nobody is answering your CQ, you're bored and it's all too hard. You've run out of things to try,
there's only so many different ways to use the radio and it's all too much.


I mean, you've only got CW, AM, SSB, FM, there's Upper and Lower Side-band, then there's RTTY, the all too popular FT8, then there's WSPR, but then you
run out of things. I mean, right?


What about PSK31, SSTV, then there's AMTOR, Hellschreiber, Clover, Olivia, Thor, MFSK, Contestia, the long time favourites of Echolink and IRLP, not
to forget Fusion, DMR, D-STAR, AllStar, BrandMeister or APRS.


So far I've mentioned about 20 modes, picked at random, some from the list
of modes that the software Fldigi supports. Some of these don't even show
up on the Signal Wiki which has a list of about 70 amateur modes.


With all the bands you have available, there's plenty of different things
to play with. All. The. Time.


There's contests for many of them, so once you've got it working, you can
see how well you go.


Over the past year I've been experimenting with a friend with various
modes, some more successful than others. I'm mentioning this because it's
not difficult to get started. Seriously, it's not.


The most important part of this whole experiment is getting your computer
to talk to your radio. If you have FT8 already working you have all the hardware in place. To make the software work, you can't go past installing Fldigi. As a tool it works a lot like what you're familiar with. You'll see
a band-scope, a list of frequencies and a list of decodes. It's one of many programs that can decode and generate a multitude of amateur digital modes.


If this is all completely new to you, don't be alarmed.


There are essentially two types of connections between your computer and
your radio. The first one is audio, the second is control. For this to work well, both these need to be two-way, so you can both decode the audio that
the radio receives and generate audio that the radio can transmit. The same
is true for the control connection. You need to be able to set the transmit frequency and the mode and you need to be able to read the current state of
the radio, if only to toggle the transmitter on-and-off. If you already
have CAT control working, that's one half done.


I've spoken with plenty of amateurs who are reluctant to do any of this. If this is you, don't be afraid. It's like the first time you keyed up you
radio. Remember the excitement? You can relive that experience, no matter
how long you've been an amateur.


Depending on the age of your radio, you might find that there is only one physical connection between your computer and the radio, either using USB
or even Ethernet. You'll find that your computer will still need to deal
with the two types of information separately.


Notice that I've not talked about what kind of operating system you need to
be running. I use and prefer Linux, but you can do this on any operating system, even using a mobile phone if that takes your fancy.


Getting on air and making noise using your microphone is one option, but
doing this using computer control will open you to scores of new adventures.


I will add some words of caution here.


In general, especially using digital modes, less is more. If you drive the audio too high you'll splatter all over the place and nobody will hear you, well, actually, everyone will, but nobody will be able to talk to you
because they won't be able to decode it. If the ALC on your radio is
active, you're too loud. WSJT-X, the tool for modes like FT8 and WSPR, has
a really easy way of ensuring that your levels are right, so if you've not
done anything yet, start there.


Another issue is signal isolation. What I mean by that is you blowing up
your computer because the RF travelled unexpectedly back up the serial or
audio cable and caused all manner of grief. You can get all fancy with
optical isolation and at some point you should, but until then, dial the
power down to QRP levels, 5 Watts, and you'll be fine.


A third issue that was likely covered during your licensing is the duty
cycle. It's the amount of time that your radio is transmitting continuously
as compared to receiving only. For some modes, like WSPR for example,
you'll be transmitting for a full 2 minutes at 100%, so you'll be working
your radio hard. Even harder might unexpectedly be using FT8, which
transmits in 15 second bursts every 15 seconds, so there may not be enough
time for your radio to cool down. Investing in a fan is a good plan, but
being aware of the issue will go a long way to keeping the magic smoke
inside your radio.


I'm sure that you have plenty of questions after all that.


You can ask your friends, or drop me an email, cq@vk6flab.com and I'll be
happy to point you in the right direction.


Next time there's nothing good on TV, get on air and make some digital
noise!


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20210214.foundations-of-amateur-radio.mp3

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What's in a prediction?

Posted: 06 Feb 2021 08:00 AM PST


Foundations of Amateur Radio


Over the past little while I've been experimenting with various tools that decode radio signals. For some of those tools the signals come from space. Equipment in space is moving all the time, which means that the thing you
want to hear isn't always in range.


For example.


The International Space Station or ISS has a typical orbit of 90 minutes. Several times a day there's a pass. That means that it's somewhere within receiving range of my station. It might be very close to the horizon and
only visible for a few seconds, or it might be directly overhead and
visible for 10 minutes. If it's transmitting APRS on a particular
frequency, it can be decoded using something like multimon-ng. If it's transmitting Slow Scan TV, qsstv can do the decoding. I've done this and I
must say, it's exciting to see a picture come in line-by-line, highly recommended.


The National Oceanic and Atmospheric Administration or NOAA, has a fleet of satellites in a polar orbit that lasts about 102 minutes and they're
overhead at least every 12 hours. You can use something like noaa-apt to
decode the images coming from the various weather satellites, or a python script and I'll talk about that at some point.


There is a growing cloud of cube satellites with interesting telemetry.
They're in all kinds of orbits and you can attempt to receive data from
each one as it's in sight.


Keeping track of what's where and when is a full time job for plenty of
people. As a radio amateur I'm happy to defer to the experts who tell me
where a piece of equipment is and when I'm likely to be able to receive a
radio signal from the transmitter I'm interested in.


Previously I've mentioned in passing a tool called gpredict that does this heavy lifting for me. It presents a map of the world and shows what's
visible at my location and when the next acquisition of signal for a
particular satellite might occur. It talks to the internet to download the latest orbital information. It also has the ability to control a rotator to point your antenna, not that I have one, and it can update the transmit and receive frequency of your radio to compensate for the Doppler effect that changes the observed frequency as a satellite passes overhead. All this
works with a graphical user-interface, that is to say, you have a screen
that you're looking at and can click on.


Whilst running gpredict, you can simultaneously launch the appropriate
decoding tool for the signal that you're trying to receive. If you have a powerful enough computer, you can run multiple decoding tools together.
You'll have separate windows for controlling the radio and antenna, for decoding APRS, SSTV, NOAA and if you're wanting to do sunrise and sunset propagation testing using WSPR, you can also run WSJT-X or any other
decoder you're interested in.


There are some implications associated with doing this, apart from needing
a big enough screen, needing considerable computing power and burning electricity for no good reason, the signal that comes in from your radio
will be fed to all the decoders at the same time and all of them will
attempt to decode the signal, even when you know that this serves no
purpose. That's fine if you don't know what you're listening to, but most
of the time you know exactly what it is, even if the software doesn't.


Manually launching and quitting decoders is one option, but what if the
next ISS pass is at 3am?


Aside from the computing requirements, so far this works fine with a
standard analogue radio like my Yaesu FT-857d. The only limitation is that
you can only receive one station at a time.


If you replace the analogue radio with an RTL-SDR dongle, you gain the
ability to record and decode simultaneous stations within about 2.4 MHz of
each other.


Another option is to use an ADALM Pluto and as long as the stations are
within 20 MHz of each other, you can record and decode their signals. If
you're not familiar with a Pluto, it's essentially a computer, receiver and transmitter, all in a little box, the size of a pack of cards.


This is where it gets interesting.


The Pluto doesn't have a screen, or a keyboard for that matter, but it's a computer. It runs Linux and you can run decoders on it. I've done this with ADS-B signals using a tool called dump1090. You'll find it on my GitHub
page.


One of the sticking points in decoding signals from space was the ability
to predict when a satellite pass occurs without requiring a computer
screen. Thanks to a command-line tool called "predict", written by John,
KD2BD and others I've now discovered a way to achieve that. My efforts are
not quite at the point of show-and-tell, but I've got a Docker container
that's building and running predict on its own and using a little bash
script it's telling me when the ISS is overhead. You'll find that on GitHub
as well.


My next challenge is to do some automated decoding of actual space signals.
I'm going to start with the ISS, predict and multimon-ng. I'll let you know
how I go.


What space signals are you interested in?


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20210207.foundations-of-amateur-radio.mp3

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Changing of the guard ...

Posted: 30 Jan 2021 08:00 AM PST


Foundations of Amateur Radio


When you begin your journey as a radio amateur you're introduced to the
concept of a mode.


A mode is a catch-all phrase that describes a way of encoding information
into radio signals.


Even if you're not familiar with amateur radio, you've come across modes, although you might not have known at the time.


When you tune to the AM band, you're picking a set of frequencies, but also
a mode, the AM mode. When you tune to the FM band, you do a similar thing,
set of frequencies, different mode, FM. The same is true when you turn on
your satellite TV receiver, you're likely using a mode called DVB-S. For digital TV, the mode is likely DVB-T and for digital radio it's something
like DAB or DAB+.


Even when you use your mobile phone it too is using a mode, be it CDMA,
GSM, LTE and plenty of others.


Each of these modes is shared within the community so that equipment can exchange information. Initially many of these modes were built around voice communication, but increasingly, even the basic mobile phone modes, are
built around data. Today, even if you're talking on your phone, the actual information being exchanged using radio is of a digital nature.


Most of these modes are pretty static. That's not to say that they don't evolve, but the speed at which that happens is pretty sedate.


In contrast, a mode like Wi-Fi has seen the explosion of different
versions. During the first 20 years there were about 19 different versions
of Wi-Fi. You'll recognise them as 802.11a, b, g, j, y, n, p, ad, ac and
plenty more.


I mention Wi-Fi to illustrate just how frustrating changing a mode is for
the end-user. You buy a gadget, but it's not compatible with the particular Wi-Fi mode that the rest of your gear is using.


It's pretty much the only end-user facing mode that changes so often as to
make it hard to keep up. As bad as that might be, there is coordination happening with standards bodies involved making it possible to purchase the latest Wi-Fi equipment from a multitude of manufacturers.


In amateur radio there are amateur specific modes, like RTTY, PSK31, even
CW is a mode. And just like with Wi-Fi, they evolve. There's RTTY-45,
RTTY-50 and RTTY-75 Wide and Narrow, when you might have thought that there
was only one RTTY. The FLDIGI software supports 18 different Olivia modes
out of the box which haven't changed for a decade or so.


The speed of the evolution of Olivia is slow. The speed of the evolution of RTTY is slower still, CW is not moving at all. At the other end new amateur modes are being developed daily.


The JT modes for example are by comparison evolving at breakneck speed, to
the point where they aren't even available in the latest versions of the software, for example FSK441, introduced in 2001 vanished at some point, superseded by a different mode, MSK144. It's hard to say exactly when this happened, I searched through 15 different releases and couldn't come up
with anything more definitive than the first mention of MSK144 in v1.7.0, apparently released in 2015.


My point is that in amateur radio terms there are modes that are not
changing at all and modes that are changing so fast that research is being published after the mode has been depreciated. Mike, WB2FKO published his research "Meteor scatter communication with very short pings" comparing the
two modes FSK441 and MSK144 in September 2020, it makes for interesting reading.


There are parallels between the introduction of computing and the process
of archiving. The early 1980's saw a proliferation of hardware, software,
books and processes that exploded into the community. With that came a phenomenon that lasted at least a decade, if not longer, where archives of these items don't exist because nobody thought to keep them. Floppy discs thrown out, books shredded, magazines discarded, knowledge lost.


It didn't just happen in the 1980's. Much of the information that landed
man on the moon is lost. We cannot today build a Saturn V rocket with all
the support systems needed to land on the moon from scratch, even if we
wanted to. We have lost manufacturing processes, the ability to decode
magnetic tapes and lost the people who did the work through retirement and death, not to mention company collapses and mergers.


Today we're in the middle of a golden age of radio modes. Each new mode

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