Foundations of Amateur Radio

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It broke and now what?

Posted: 10 Aug 2019 09:00 AM PDT


Foundations of Amateur Radio


It broke and now what?


Imagine you're a new amateur. You've woken up in the middle of the night
because insomnia seems like a good way to use amateur radio as an excuse to
get on air and make some noise. You turn on the radio, key up the
transmitter and the next thing you know it's dark. The breaker that powers
your radio popped and there's no more glow coming from the hardware that's
warming up your shack.


You get up, reset the breaker, tighten up your dressing gown and switch on
your gear. You sit down and key up. Pop, darkness.


What do you do next?


The first thing to realise is that there is something wrong. That might
sound obvious, the radio just tripped the breaker and it went off, but
sometimes it's not that obvious, sometimes there's something wrong, but
it's not nearly as clear as light and dark. For example, you might key up
and the SWR goes high. You might not even notice if your radio is set to
monitor the power output, or the automatic gain control that indicates how
well your audio is going out.


The point is that noticing that something is wrong is a matter of paying
attention. Just sitting there all dumb and happy, mashing the microphone is
going to cost money or cost something else one day when you stop paying
attention.


So, finding out what's wrong starts with noticing that something is amiss.


If you've been clued in that something is broken, and you're not standing
next to your radio with a fire extinguisher, or tears running down your
cheeks because you just blew up your new radio, you can move onto the next
part of this little adventure.


One thing to note is that it's really easy to make it worse at this point.
Making it worse arrives in all manner of different ways, pain, either
physical, RF burns, smoke, sparks, or mental like the emptying of your
wallet when it goes pear-shape.


The art of troubleshooting is the process of attempting to learn what's
going on. Some people know instinctively how to do this, others just wiggle
stuff, unplug stuff and hope for the best. Hoping for the best is not the
best plan.


One of the most basic aspects of troubleshooting, of trying to figure out
what's happened, is to document what you find. Write it down. I know you're
going to skip this, but it's going to bite you and then you'll be sorry and
I'll be here telling you that I told you so. So write it down. Be
meticulous. In case you're wondering, you're doing this for your own
benefit, not my sense of curiosity. If you measure a value now and it's 7
Ohm and you change something and then you measure again and it's 23 Ohm, if
you didn't write it down, you'll never know. Especially if the two
measurements are a week apart.


Next basic concept is to change as little as possible, preferably one thing
at a time. That's easy for me to say while your reptilian hind-brain is
currently attempting to decide between whom to murder first and how fast to
run. There is a tendency during panic to wildly wave your hands about and
fiddle with lots of stuff. The urge to do that is strong. Resist that urge
with all that you have. Again, you're going to ignore that and I'm going to
stifle my I told you so chant, but less is more. This is important. If you
change two things, you've just doubled the possible causes. If you change
three, there are now six different causes and if you change four things,
we're up to 24 different versions of the problem. Keep it simple.


Third concept is to test things. The smaller the test, the better. For
example, you're connected to the right antenna, right? The power supply is
giving out the right voltage, right? The squelch is open, right? The
microphone is plugged in, right? Test each of those, one at a time. The
more you troubleshoot, the more this list will come naturally. Right now
you're probably cursing me for not supplying you with a ready-made list.
That's because my shack is nothing like yours, not even a little bit. Also,
your shack keeps changing. Besides we're learning the skill of
troubleshooting and I already know how to do that. Mind you, truth be told,
I've been known to make mistakes too, so there's that.


Forth concept is about testing gear. There is a tendency within our
community to buy gadgets. The more the better, a volt meter, an ohm meter,
an ammeter, an SWR meter, an oscilloscope, a VNA, a what-ever. The more
toys the better. While toys, uh tools, help, they're not the answer to
every question. You have a more fundamental issue to deal with. Garbage in
equals garbage out. If you measure ohms, but needed volts, there's no
helping you. So, instead of focussing on what new tool to acquire, focus on
what measurement you need to make to prove that something works, or doesn't.


The process of troubleshooting doesn't come naturally to everyone. I know,
I've seen some very panicked people break some very expensive hardware,
seen full-bright scholars make bonehead mistakes and heard stories of
physicists narrowly avoiding electrocution, so don't be shy when you say
that you're not sure how to really do troubleshooting.


You can learn. We all did, me included.


I'm Onno VK6FLAB
This posting includes a media file:
http://podcasts.itmaze.com.au/founda...teur-radio.mp3