[continued from previous message]

radio amateur friends who prodded and poked, who helped and asked, who gave
and received. My exposure over this decade was only possible because there
are others who share my interests and stopped to take a moment to express
that.


Next time you're asked about how amateur radio is relevant, how it relates
to the world, how it affects you and your life, what it's given you, or
what you can gain from it, consider, even just for a moment, just how much
is possible within this massive hobby.


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20200719.foundations-of-amateur-radio.mp3

///////////////////////////////////////////
Homebrew radio for the 21st Century

Posted: 11 Jul 2020 09:00 AM PDT


Foundations of Amateur Radio


The hobby of Amateur Radio is essentially one of experimentation. Within
our community we endlessly build things, from amplifiers to Yagis and every letter of the alphabet in between. With every experiment we grow the
amateur radio sphere of influence just a little bit.


As our hobby is evolving into Software Defined Radio, or SDR, the homebrew aspect of our community is also changing bit by bit and as a result,
homebrew today is just as likely to be based on software as it is in
hardware.


Unlike the physical world where you need to source and buy components,
design a circuit, build it, test it and then put it in a box, in the
software realm you can get started with the computer that is more than
likely within reach right now.


Recently I took delivery of a new SDR, an ADALM Pluto. It's essentially a
Linux computer, FPGA and transmit capable SDR in a small box. I bought it specifically for the purpose of experimentation.


One of the first things I did with this device was install an existing
piece of software called dump1090. The tool listens to 1090 MHz and decodes Mode S transponders, used by aviation to report aircraft information in real-time.


Originally written by Salvatore Sanfilippo in 2012 for the RTL-SDR dongle,
it was patched by several people and in 2017 it was updated by Jiang Wei to support the Pluto SDR. My contribution to the project is minor. I've
updated the on-board web-server to use Open Street Map and a few other
cosmetic changes.


For me it was a "Hello World" project, something that's the software
equivalent of warming up your soldering iron and pre-tinning the wire
you're about to use.


The tools to do this is what I want to discuss.


When you look at the software that underlies much of the SDR world, the
digital modes, logging, contesting, even the software inside tools like the Nano-VNA, much of it is open source. That means that as a curious amateur
you can have access to the underlying equivalent of the circuit diagram. As
you can with a soldering iron, a scribe and wire, you can patch or update a circuit. In the software realm you can do the same once you have access to
the source code.


The tools you're going to get in touch with are text editors, compilers, libraries and configuration files. If that's not your thing, I appreciate
that, but if it sparks your interest, you'll open the door into a brand new world of software development where you can determine how a mode works or
what it supports or how it interacts with your radio or testing gear.


When you jump in, likely feet first, you're going to make mistakes and lose hair and sleep and you'll be shaking your virtual or physical fist at the person who came before you, but then that's the world of experimentation,
so likely you'll already have that down pat.


You'll likely play with different tools that require different versions,
often installed side-by-side, much to your chagrin when you learn that it
just won't work. Not to mention that removal of the offending tool often
leaves interfering cruft behind, not unlike unsightly and short-circuiting blobs of solder.


I'm here to introduce you, albeit briefly, to a tool that will take much of that pain away. The free tool is called Docker. It has got little in the
way of visibility in the amateur radio world, but in the software
development world it's pretty much old hat.


Essentially the idea is that you can install stuff into a so called
disposable container so you can have your copy of dump1090 installed in one container and your copy of codec2 in another, a copy of rtl-sdr in a third container, all working independently from each other, without needing to complicate things with multiple computers or virtual machines. If a
developer uses Debian, another uses Ubuntu and a third uses Red Hat, you
can run these side-by-side without any issue. If they need an ancient
version of something, that too is handled without a problem. Make a
mistake, destroy the container and start again, fresh.


Docker is a tool that allows you to build an environment on Linux, MacOS
and Windows, as well as the Raspberry Pi, that acts and behaves in many
ways like a virtual machine. In all the ways that you're likely to use it,
at least initially, it's indistinguishable. What that means is that the operating system, the compiler and the libraries that you need for one tool won't affect those needed for another tool.


The best part of this is that you can build on a massive library of pre-existing Docker containers and use files that describe how to build and compile tools like dump1090.


If you look for my callsign vk6flab on github.com, you'll find my version
of dump1090 and you'll find a Dockerfile that describes how I built it. The project contains all the bits you'll need to get started with your own
version of dump1090, or some other project that tickles your fancy.


Every time you build something, the amateur radio sphere of influence grows just that little bit.


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20200712.foundations-of-amateur-radio.mp3

///////////////////////////////////////////
What is a repeater offset and how does it work?

Posted: 04 Jul 2020 09:00 AM PDT


Foundations of Amateur Radio


Every week I run a net for new and returning amateurs. A variety of people
join in with varying degrees of skill, knowledge and number of birthdays.


One of the regular things I say during that net is that if I'm not acknowledging you, it's because I cannot hear you. I then start a spiel
about repeater offsets and give some examples, but what is it really and
how does it work?


As you might recall, a repeater is a radio, generally located somewhere
useful, like on a hill or tall building, that offers the ability to talk to other amateurs who are not within range of your radio.


For bands like 2m, 70cm and 23cm, generally speaking, contacts are line-of-sight. If you're standing on a hill, you can talk to more people because your line of sight is further away.


This is also why you can talk to the International Space Station with a hand-held, since it's in your line-of-sight, at least some of the time.


A repeater acts as a line-of-sight extender. If it can see both you and
another station, it can act as a bridge between you.


How it does this is pretty simple. A repeater listens to your signal and transmits that to the other station. It uses two separate frequencies to
make this happen. A receive and a transmit frequency, or more precisely an input and an output frequency. To remember which is which, you can think of
a repeater as a giant megaphone, you talk into it and sound comes out. Said differently, think of a repeater as a device that takes an input from one station and makes an output for everyone to listen to.


To actually use a repeater, your radio needs to be setup to transmit on the repeater input and it needs to receive on the repeater output. This means
that when you transmit, the repeater can hear you and when you're
listening, you can hear the repeater.


To achieve this, you can set your radio up using repeater mode. It uses a
thing called an offset to set the difference between the input and output frequencies.


To find out what the offset is, you take the repeater input frequency and subtract the repeater output. If you've set-up your radio correctly you're tuned and listening to the repeater output. When you hit the Push to Talk
or PTT, you'll transmit on the input frequency and when you let go, you're
back to receiving on the output frequency.


One final roadblock might be that your local repeater has a tone lock. If
it does, the repeater will ignore you even if you have all the frequencies correct. This tone is generally published by the repeater owner or your
local regulator. You can also check a website called repeaterbook.com to
see many of the world's repeaters and their specific settings.


Now, I should point out that while repeater offsets are standardised,
they're not the same across bands, across the world, or even within a
country or city. Depending on where you are, what the density of repeaters
is and what band you're on, the offset number and direction will change.


It's even possible that you have a variety of offsets on the same band in
the same city. This means that you cannot just pick a standard offset for
your radio but most modern radios will have a method to deal with this.


It's easy to get this wrong.


Setting up your radio for using a repeater is deciptively simple. Three
things to look out for when it's not working. You have the input and output reversed, the offset is wrong, or there's a tone blocking your transmission.


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20200705.foundations-of-amateur-radio.mp3

///////////////////////////////////////////
Your antenna is a filter (of sorts).

Posted: 27 Jun 2020 09:00 AM PDT


Foundations of Amateur Radio


The single most discussed topic in amateur radio is that of antenna design, that and medical procedures on 80m, but I kid. Previously I've discussed
the notion that all frequencies are on-air all the time and that your traditional radio uses much of its electronic circuitry to filter out all
the things you don't want to hear.


Parallel to that is the concept that you tune your antenna to be resonant
on a particular band or frequency. As amateurs we might look for a
wide-band antenna that makes it possible to use our radio across several
bands. We often construct our antennas to be multiple harmonics of a band
so we can have access to more spectrum without needing more physical
antennas.


None of this is new and as an amateur you'll likely spend the rest of your
days improving your antenna situation, or at least talking about it, if not outright bemoaning the lack of antenna space, family approval, budget or
some other excuse.


As I started my journey into Software Defined Radio a new idea occurred to
me. If an antenna is a resonant circuit, could you think of your antenna as
a filter, as-in, something that leaves out the things you don't care about?


In and of itself I'm sure I'm not the first to consider this notion, but
the idea means that you essentially turn your idea of an antenna on its
head, from something that receives to something that rejects.


Consider for example the small transmitting loop antenna, often also called
a magnetic loop antenna. It's got one characteristic that isn't often considered a benefit, it has something called a High-Q, or a high Quality Factor. The higher the Q, the narrower the bandwidth.


I should digress here for a moment. Q is a number. Big number means narrow bandwidth, little number means wide bandwidth. It's easy to calculate. If
you look at an SWR plot of an antenna you'll see a curve where the bottom
of the curve is the lowest SWR of your antenna, that's the centre
frequency. You'll also see two points on the same curve where the SWR hits
2:1. If you take the centre frequency and divide that by the difference
between the two edge frequencies, you'll have the Q of that antenna.


Using numbers, consider an antenna that's got an SWR below 2 between say 7
MHz and 7.2 MHz, a bandwidth of 200 kHz, you'd have a centre frequency of
7.1 MHz. The Q of that antenna would be 7100 divided by 200 or a Q of 35.5


If you had an antenna that had a bandwidth of 5 kHz at 7.1 MHz, it would
have a Q of 1420.


And just to wrap that up. This is helpful because just comparing bandwidth
on different antennas doesn't tell you enough. Is an antenna that has 400
kHz bandwidth on 20m more or less selective than an antenna with 200 kHz bandwidth on 40m, what about 100 kHz on 80m?


Back to the small transmitting loop antenna or mag-loop. If you're using
such an antenna on an amateur band like say the 40m band, you'll likely
have to re-tune your antenna every time you even think about changing frequency. I've had the frustration of using a manual version of such an antenna and it can wear thin very quickly.


I'm bringing this up because it can also be a benefit.


Imagine that you need to make a contact on a busy band during a contest.
Often you'll find yourself setting up the filters on your radio, trying
hard to remove all the extraneous noise that comes from strong signals
nearby.


What if your antenna could help with that?


What if you thought of your antenna as a pre-filter, something that makes
the job of extracting just that signal from the bit of spectrum you're interested in?


My point is this.


We're talking about an antenna that from one perspective can be a pain to
use, requiring constant retuning, constant adjustment, just to get on the
air and make noise.


From another perspective, that very same antenna is a way to filter out the things you don't want to hear and extract the signal you care about.


How you approach this depends on your perspective and just considering your antenna as a filter might help you see another side of your antenna system
that you hadn't considered before.


How you use this is entirely up to you. For my money, I'll be doing more experiments.


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20200628.foundations-of-amateur-radio.mp3

///////////////////////////////////////////
If you WSPR and nobody hears you ...

Posted: 20 Jun 2020 09:00 AM PDT


Foundations of Amateur Radio


The day came to pass when all my set-up and configuration was going to culminate in the moment of truth when I enabled TX on my WSPR mode station. Before I tell you of my experience, I should give you a little bit of background.


A few weeks ago I managed to erect a HF vertical at my home or QTH. That in
and of itself was news worthy, well at least to me it was, since it was the first time since I became licensed in 2010 that I had actual real all-band
HF capability at home. Last weekend I ran some RG6, yes, 72 Ohm Quad
Shield, low-loss coaxial cable, from my antenna, through the roof, into my shack.


I was thrilled.


Immediately set about getting my HF station up and running. This involved installing WSJT-X, a tool that allows you to do weak signal work, perfect
for when you're a low power or QRP station like me. I've previously
reported using WSPR, Weak Signal Propagation Reporter on a Raspberry Pi and
a dongle, but this time I was using my Yaesu FT-857d.


Reports were coming in thick and fast. Managed to hear stations on all the bands I'm allowed on, 80m, 40m, 15m, 10m, 2m and 70cm. Managed to make it report online and update the various maps around the place.


Brilliant!


Now I wanted to do the next thing. Transmit and see who could hear me and
how far my beautiful callsign might travel on 5 Watts.


So, after some abortive attempts, I configured the levels correctly, made
sure that my antenna coupler, an SG-237, was tuned and hit "Enable TX" on
the screen of my computer.


Dutifully my computer did what was expected, turned on the transmitter and happily made the fan run on my radio for two minutes at a time. I tried
80m, 40m and 15m. All worked swimmingly.


Then I looked on the map to see who had heard me.


Nobody. Nothing. Nada. Niets en niemand.


I could hear N8VIM using 5 Watts, 18649 km away, but nobody could hear me,
not even the station VK6CQ who is 9 km from me.


So, what's going on?


Turns out that I'm not using a "standard" callsign. That's right, my
VK6FLAB, authorised by the World Radiocommunication Conference 2003, implemented by the Australian regulator, the ACMA in 2005 and issued to me
in 2010 isn't a standard callsign.


Seems that the deal-breaker is the four letter suffix, FLAB, that's killing
my attempts at making contact.


Now I know that there are moves under way, not quite sure what stage
they're at, to allow Australian amateurs to apply for any three-letter
suffix and keep that regardless of their license level, but that to me
doesn't really solve the underlying issue, where a perfectly legal callsign isn't allowed to be used by one of the most popular modes today.


I've lodged a bug report on the WSJT-X mailing list, but to accommodate
this callsign will probably require a fundamental change in the way the
WSPR mode and likely several other JT modes will work, not to mention the databases, the maps, API calls and other fun things like logging.


Technically I could have figured this out back in September 2019 when I was first allowed to use digital modes with my license, but I didn't have an antenna then.


In case you're wondering. I also investigated using a so-called extended,
or type-2 message, but that allows for an add-on prefix that can be up to
three alphanumeric characters or an add-on suffix that can be a single
letter or one or two digits.


I could use something like VK6FLA/B, but I'm sure that the owner of VK6FLA would be upset and using VK6/F0LAB might have a French amateur yell Merde!
at me when they spot their callsign being transmitted from VK6.


One suggestion was to upgrade my license.


What's the fun in that?


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20200621.foundations-of-amateur-radio.mp3

///////////////////////////////////////////
Using something for an unexpected purpose can give you many great rewards.

Posted: 13 Jun 2020 09:00 AM PDT


Foundations of Amateur Radio


The other day I was getting ready to go out when rain started pelting down.
Not unexpected in this part of the world at this time of year but
inconvenient for my plans.


I didn't particularly want to carry an umbrella and the thought of wearing
a rain hood brought back memories of water trickling down my back.


For reasons I'm not quite sure of, my eye fell on my hat on its hook at the door. The hat I wear in the heat of summer to keep my brain from frying,
the hat I use whilst camping with my amateur radio friends, the hat I've
worn whilst loading massive hay bales with a tractor and the hat I've worn swimming in the Ord River - well, a descendent, third generation if I
remember correctly. I shook my head in disbelief, after donning my
raincoat, put my trusty Akubra Territory on my head and stepped out into
the rain. Perfect. Kept me dry, kept my glasses clear and no drips down my back.


You may well wonder what this has to do with radio and that's a fair
question. I will preface this with a disclaimer that you might not have
this set-up in your shack just now, but perhaps it will inspire you to get started.


I've been talking a lot about Software Defined Radio, and I do believe that
it represents the future for our hobby, but that doesn't mean that my traditional radio, in my case a Yaesu FT-857d, is headed for the scrap heap just yet.


As you might know, with some preparation you can connect your radio to a computer and control it. You can also connect both the send and receive
audio to a computer using a variety of techniques which I probably should
get into at some point.


Assuming that you have, and I realise you might not yet have done this, but assuming for a moment that you have made this all work, you can use this to
do things like JT65, FT8, PSK31, SSTV and hundreds of other modes.


One thing I did during the week was use this set-up to listen to noise. Seriously, that's what I did. I picked a spot on the band with nothing but noise. No discernible signal and fired up the application WSJT-X, it's the
tool you use for many weak signal modes. As an aside, as a tool, it is also helpful in getting your digital mode levels set correctly.


One of the windows in WSJT-X is the waterfall and spectrum display. On it
you can see the signal as it is right now and how it's been in the past.


If you turn on one of the filters on your radio, you can see the display change. You can literally see what gets filtered out. On my radio I've got
the standard filter, as well as a 2 kHz and a 300 Hz Collins filter. Using
this technique, you can specifically see what each filter does. If I turn
on the built-in Digital Signal Processor, the DSP, I can see what the adjustments do, as well as the impact of the mode on the filter. And how
the various settings interact.


For example, until I saw this display, I didn't know what the "DSP HPF
CUTOFF" and "DSP LPF CUTOFF" specifically did and how they interacted with
the other filters. Similarly what "DSP BPF WIDTH" did and how.


I also didn't know that even if you set both the high and low pass filter frequencies to the same value, you still have a usable filter, even if you might think that nothing could get through.


Now I do realise that your radio may not have those specific settings, but
I am confident that if you pick a spot on the band, set up a frequency
display and waterfall, you'll discover things about your radio that you
hadn't before. I also realise that you can hear some of this by just
playing with filters, but seeing it on the scope adds a whole other
dimension to the experience. Just one example is to see how a narrow filter interacts with the in-built DSP, something that's difficult to hear, but
easy to see.


If you have a Morse beacon to hand, you can also see how various frequency shifts work and the impact of selecting filters in relation to that signal.
No need to just listen to the beacon with just CW mode either. Have a look
at it using SSB.


Using something for an unexpected purpose can give you many great rewards.
As for the hat, really, I hadn't used my hat to ward off the rain until
then; you live and learn.


What have you discovered recently?


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20200614.foundations-of-amateur-radio.mp3

///////////////////////////////////////////
How to pick a field operating position?

Posted: 06 Jun 2020 09:00 AM PDT


Foundations of Amateur Radio


Much of the operation that I've done as a radio amateur is conducted in the field. That is, I tend to either drive my car to a location, or go out with friends and set-up camp to play. After you do this for a while you start to notice the things that you look for in an operating position.


The very first one is accessibility. That is, how easy is it to get there?
It's fine coming up with the ultimate location, but if it's an hour's drive away and you've only got an hour to play, you'll spend all your time
getting there and you'll be home late.


By contrast, for field days lasting several nights, I've regularly driven
more than a hundred kilometres to find the spot, sometime much more than
that. The point is that the accessibility changes depending on your
available time. The journey to the location can be just as much fun as the destination itself.


How long you plan to be there will determine what antennas you might want
to set-up. If you're there for an hour, you'll likely use a vertical on
your car. If you're there for the weekend, your antenna farm will be
determined by how much wire you brought and what you can hang it off.


Hanging antennas is the next thing. You can bring your own poles, but for height, nothing beats a solid tree. The taller the better. More taller,
more better. If you have several to choose from, you get to play with all manner of fun stuff. For one antenna contraption we had three trees that we
ran a wire between. They were roughly spaced in a triangle about 200 meters apart from each other. As I recall, the antenna we built, a massive V-beam managed to talk to Europe for most of the weekend.


For another adventure a simple G5RV dipole was hoisted high into the trees. Another was accomplished by strapping a pole to a fence and setting up an inverted-V antenna. Recently we set-up an antenna that was nothing more
than a wire running over the ground.


So, generally speaking height is good. You can cheat by having a low tree
and a hill. Or a fence and a pole, or a gazebo and tent-pegs. What ever you
can do to attach an antenna to will work to some degree. Which reminds me,
if your hill is tall enough, it's likely to have a communications tower on
it for someone, if not everyone. They're not the end of the world, but they
can cause havoc with noise. Depends entirely on what the communication structure is used for. Bear in mind, some of these sites have noisy solar
panel inverters or generators, so that too needs to be taken into consideration.


Another factor in picking a location involves water. Setting up a vertical
on a jetty is gold. I've made many long-distance contacts using a vertical
with a ground wire running into the ocean. Note that you don't have to
actually get wet. Being near the ocean is often enough. I've had plenty of success from a beach car-park from a vertical on my car.


In general, man-made objects such as houses, factories, other cars, power lines, generators, boats, camping grounds with solar panels and plenty more
are often bad news for HF communications. The biggest disappointment
happens when you take the time to go to a site, set up camp, build your antennas, turn on the radio and all you hear is the noise from a nearby
source of interference.


That said, you don't need to travel to the ends of the earth either. 15
minutes from my house is a lake with a park. There's a car park which on occasion attracts a motor home with a solar panel, but by enlarge it's a
local park with people going for a walk. From a radio perspective, despite homes, businesses, schools and cars nearby, the place is heaven. It's
quiet, it has shade, running water, fence posts and I regularly make
contacts from there, right in the middle of the city.


That brings me to another aspect. Creature comforts.


Setting up near a busy road isn't fun. Neither is sitting in your car
without shade. Having amenities within reasonable distance helps. For
example, recently for a field day we set-up within 10 minutes drive from a regional centre. Didn't even notice it was there, happily dropped in for shopping and a meal. Some beers might have been consumed.


That same site also had high voltage power lines near our location. The
only difference was that our site was above the power lines at the top of a hill, so we never even noticed them.


Finally, some of this is all about picking a camp-site that's suitable for radio, rather than a radio site that will handle camping. You get better at
it the more you do it. If you check back after the adventure, you'll learn
some stuff as well, so don't be shy to discuss your experience with your friends.


What ever you do, practice makes perfect.


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20200607.foundations-of-amateur-radio.mp3

///////////////////////////////////////////
The humble coaxial cable

Posted: 30 May 2020 09:00 AM PDT


Foundations of Amateur Radio


If you've ever used a spray can of WD-40, you might have wondered what the
name means. It stands for "Water Displacement, 40th formula". In my time as
a radio amateur I'd never stopped to think what the RG in RG-58 stood for. Turns out that it too has a meaning, "Radio Guide", though I have found
some interesting alternative descriptions where the G stood for Government.


This radio guide, really a transmission line, gets a signal from point A to point B. Depending on how you construct that transmission line determines
what you'll get at the other end.


Coaxial cable or coax is a length of cable made from several components. There's the outer layer or jacket, that protects the cable from electrical shorting, U/V deterioration and water ingress which causes all manner of problems. Inside that is an electrically conductive shield that forms one
half of the transmission line, inside that is a dielectric, essentially a separator or insulator between the shield and the inner most, or central conductor, the core.


Each of these components can change. On the outside the first thing you
might notice is the thickness of the cable. The next thing you might
observe is how flexible it is. Below the outer surface other things can
also be altered. For example, the core could be a solid copper wire, or it could be strands of copper. It could be aluminium, silver or even steel. It might not even be wire. Some coax like Heliax, used in broadcasting, uses a central conductive tube as the core with air as the insulator between the
core and the shield.


The dielectric that separates the core from the shield can be made from different materials such as plastics, air and even inert gas such as
nitrogen and it comes in varying thickness. Similarly the shield can vary
in thickness, material and construction. There are also variations that
have multiple levels of shielding, such as for example Quad Shield RG-6,
common in satellite television and internet connections that has four
layers of shielding.


Other aspects might not be nearly as obvious. If you're running coax down a power line it will need physical strength. If you're burying it in the
ground it will need to be protected from water ingress. Temperature and
heat dissipation are also considerations and if you're using the coax in a nuclear reactor, its ability to deal with radiation. More commonly if you
need to run the coax around a corner, how tight it can be bent is another consideration.


As the materials and dimensions are changed, the characteristics of the
coax changes. Each of these are documented and standardised.


The standardisation is both a blessing and a curse. So many options and so
much to choose from.


For example, if you compare RG-58 to RG-59 they look pretty similar. If you
cut into them you'll notice that they're made from similar materials. If
you put them side-by-side, you'll notice that RG-59 is thicker, by about
20%, conversely the core for RG-59 is thinner by about 20%, this also means that the dielectric is about 30% different in thickness. As a consequence, connectors for one might fit on the other, but rarely work well.


These variations mean that while both types of coax are common and priced similarly, they're not interchangeable. RG-59 used to be common in
satellite TV installations and is still used in CCTV, whilst RG-58 is
common in radio communications.


If you made the decision to actually go out and buy RG-58, you'll come
across many variations indicated by extra letters. For example, BC means
Bare Copper and TC means Tinned Copper.


The final piece of the puzzle in this tangled offering of transmission line
is that each manufacturer has their own way of doing and naming things in pursuit of market share. For example, the coax I installed recently is
known as LMR-400, CNT-400, WBC-400 and several others.


If the performance of your coax actually matters that much, I'd recommend
that you spend some time looking at your options before handing over any
money.


All that behind the name of a piece of coax that runs between your radio
and antenna.


I'm Onno VK6FLAB
This posting includes a media file: http://podcasts.itmaze.com.au/foundations/20200531.foundations-of-amateur-radio.mp3

///////////////////////////////////////////

[continued in next message]

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)