Foundations of Amateur Radio

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What does MARS have to do with Amateur Radio?

Posted: 04 Feb 2017 09:00 AM PST


Foundations of Amateur Radio In my travels along the highways and byways
of the Internet I came across several references to MARS in relation to
Amateur Radio. Being the curious soul that I am, my interest was sparked. I
must warn you, today there is a lot to cover. First up before I tell you
anything, let me start by pointing out that what I'm talking about has
different levels of application depending on where you are on the planet. I
also need to inform you that in some parts of the globe this is considered
illegal, where in other parts of the same globe, it's perfectly fine. So,
MARS, or MARS/CAP if you want to get more precise. What is it, how does it
work and what do you need to know about it? MARS is an acronym for
Military Auxiliary Radio System and CAP is an acronym for Civil Air
Patrol. Given that we don't have such things in Australia, this phenomenon
relates to the United States of America where MARS/CAP is used to
coordinate search activities and relay messages on HF and VHF frequencies
near Amateur Bands. As an interested party you can join up, do training and
participate. That aside, the term MARS/CAP is more widely referred to as a
way of modifying your radio to allow it to access to frequencies outside
the Amateur Bands. Now at this point if you're a licensed Amateur your ears
should have pricked up when you heard the words "modifying your radio"
and "outside the Amateur Bands". This is as I already said, legal in some
parts of the globe and not in other parts. So, a MARS/CAP modification
extends the frequency coverage of your radio. Some modifications involve
extending what frequencies you can receive, others extend the transmit
frequencies. Often these changes are separate, but not always, so make
yourself aware of what you're doing before you do anything. Now why am I
telling you about something that some might consider shady or illegal?
First of all, I've not actually told you what to do or how to do it.
Second, if you're trawling through the Internet and you come across such a
thing, how would you know what it means in your situation, other than a
list of instructions shown on some random website? There are several
different aspects to this. As I mentioned, the legal aspect which I'll
discuss a little more later. There's also the technical, performance and
warranty aspects to consider. Not to mention, emergencies and other
exceptions. From a technical perspective, there are generally two types of
MARS/CAP modifications. There are hardware ones where you pull out your
soldering iron and modify the circuit on your radio by adding or removing
something. There are also software modifications where updating the version
of the software on your radio, or changing a flag, or setting a memory will
make the modification. The hardware changes are generally pretty permanent,
the software ones are often able to be reverted back to normal, but not
always. While I'm warning you, some radios when opened up reset their
memories, so you may need to reprogram all those channels when you put it
back together again. Now, your Amateur Radio is a finely tuned animal.
It's specifically configured to work within the specifications of the
Amateur Bands and regulations and as you should know, there isn't a single
piece of hardware that exists that isn't subject to the variation of its
components. This means that if you compare two identical radios, the same
batch, the same builder, they still are not identical. If you put them on a
testing bench, you'll notice subtle differences. They'll be close, but not
the same. Each one is specifically set with preferences, variable
capacitors, inductors and resistors to respond just so, and meddling with
the hardware or software can - and likely will - change this finely
balanced piece of gear. If you're fiddling to fiddle, be aware that you
might never get your radio back to the way it was before you changed it.
If you let the magic black smoke out of your radio and return it...
This posting includes a media file:
http://podcasts.itmaze.com.au/founda...teur-radio.mp3