Foundations Of Amateur Radio

Foundations of Amateur Radio Recently I talked about making a propagation map in your mind by listening to the various NCDXF beacons across the globe on various HF bands. You're not limited to listening to a beacon to learn what propagation is like. If I tell you that listening to a band gives you an indication on what's going on, you're likely to respond with: "Duh". But what if I suggest that instead of listening to a DX station running a pile-up, you instead listen to the stations calling? Back in January 2014, episode 133, when this series was still called "What use is an F-call?", I explained what "Listening 10-up" means and how you operate in a so-called split mode. As you might recall, working split is about dealing with the phenomenon that a weak DX station working in some desirable location is likely to be overwhelmed by stronger signals, to the point of no longer being heard. It's a good skill to learn and you should try and work both sides, being the station calling a DX, but also being the one

Foundations of Amateur Radio Technology is a moving feast. New ideas spring new inventions which in turn change our lives. Amateur Radio is at the forefront of such inventions. Radio Amateurs have been until recently the only soldering iron brigade around. We've been building things for over a hundred years and we continue as a community to think of new ideas and ways to make them happen. For example, we take technologies like AllStar Link, EchoLink, Wires and so on all in our stride. We think nothing of having our radios connected to each other using techniques other than radio spectrum. In November 1997, when iPhone still meant Internet Phone, an inquisitive 22 year old amateur called Dave Cameron VE7LTD came up with a way to link a radio to the Internet and the first three Internet Radio Linking Project stations were connected to each other and the now global network of IRLP nodes was born. Dave built a DTMF decoder which allowed remote control of a computer and the radio that was attached to it, and m

Foundations of Amateur Radio The world is your oyster, but sometimes you need to find a way to test what is going on with your station and determine what is working and what isn't. Often I turn my radio on to scanning mode and I set it to scan the Northern California DX Foundation beacons. These beacons, perhaps better known as the NCDXF beacons can be heard across five different HF frequencies, on 20m, 17m, 15m, 12m and 10m. These beacons repeat in a cycle that lasts three minutes, covering 18 different transmitters located in countries scattered around the globe. Beacons exist in New York City at the United Nations, in two other locations across the US, in Canada, New Zealand, Australia, Japan, Russia, Hong Kong, Sri Lanka, South Africa, Israel, Finland, Madeira, Argentina, Peru and Venezuela. Each beacon rotates through each frequency and then waits three minutes to transmit on the same frequency again. Each transmission contains the station callsign, sent in 22 words per minute Morse code, followed by

Foundations of Amateur Radio Recently I made a comment about melting your coax and that this was a bad thing. Today I'm going to talk about some of how this comes about and what kinds of parameters we're dealing with. Let's start with coax itself. The operating temperature of coax is somewhere around 80 to 90 Degrees Celsius, or 176 to 194 Fahrenheit. Soldering is at 230 Celsius, or 446 Fahrenheit, so for starters, soldering coax is a risky adventure. For argument's sake, let's assume that you managed to solder your coax without damaging it. What else can go wrong? Let's have a look at high voltage transmission lines. Why do we move power around the place using high voltage lines? The answer is that in a high voltage line, the current is low. Where the current is low, heating is low, so more of the energy gets from the power-station to your shack and less of it is used to heat up the power line between the power station and you. So, that means that high voltage and low current is less heat loss. The oppo

Foundations of Amateur Radio Today I'm going to talk about SWR or Standing Wave Ratio. As amateurs we use this term all the time, we expect to see it on a meter or display near our transmitter, we buy specific gadgets to measure it and often we seek to find the lowest possible SWR. As I've said in the past, the perfect antenna cannot exist, in the same way, a perfect connection, the feed-line, between an antenna and transmitter can also not exist. The perfect match is a 50 Ohm match, but a dummy load is a perfect match and its purpose is specifically not to radiate. So what's all this about then? Lets start in a swimming pool for a moment. Imagine that this pool is really long and skinny. Say 100m long and 1cm wide. Stand on one side and make a splash. The ripple of the water radiates from the source of the splash, you, to the other end of the pool. The end wall bounces the ripple back to you, and bounces back and forth until all the ripples have dissipated. Now, if you kept splashing about, and waves w

Foundations of Amateur Radio One of the tick boxes we're required to deal with is the one titled "Station Security". As licensed amateurs we're required to secure our station from use by unauthorised people. What form does that take, how do you do it, what makes it secure and how much security is enough? I spent a bit of time looking around to see if there were any guidelines I could unearth to actually describe in detail what this might actually mean, but my Google Fu is clearly broken, since I was unable to find any such documentation. That's not to say that it doesn't exist, just that it's well hidden among the hits about encryption, broadcasting music and other spurious results. What form does this requirement take in your shack? Do you tick the box and move on, or have you taken specific actions to comply with this requirement? For me, I have two shacks. One in my office and one in my car. Taking the car first, the security of my mobile shack is based around the notion that my car is locked when I'm

Foundations of Amateur Radio Radio Waves travel in straight lines. They go from point to point and that's it. Except that Radio Waves also reflect off certain surfaces, like light does. So, Radio Waves travel in straight lines and they also reflect and that's it. Except that Radio Waves also change direction when they pass through some change of medium. So, then, Radio Waves travel in straight lines and they also reflect and refract and that's it. Except that Radio Waves also bend when they encounter an obstacle or a slit. So, ok that's it. Radio Waves travel in straight lines and they also reflect and refract and diffract and that's the end of it. Except that they turn slightly due to gravity when they pass by a large mass. So, this phenomenon that we use in our hobby every time we key up a transmitter or listen to an off-air signal is doing much that is invisible. It bends and wobbles, bounces and shifts, reflects and refracts and somehow we still manage to make our signal get from here to there. The

Foundations of Amateur Radio To do the same thing over and over again and expect a different outcome is the definition of insanity; so how do you avoid making the same mistakes on-air in Amateur Radio? During the week I was wading through some old photos and videos on my phone to make some space and I stumbled on some old videos taken by others and sent to me whilst I was on-air. It was a lovely look back at some previous activity, but they also made me cringe. Here's one example, the very first time, back in 2011, I did a local contest, using the club callsign VK6AHR: == One One. My number to you is uh, one zero four, uh V K Six Alpha Hotel Romeo to V K Six Alpha Romeo, my number to you is one zero four. == It's only that I know I was using the club callsign that I know who I am and who the other station is, in this case the other station was VK6AR. My exchange was 104, but clear as mud and twice as thick. These days I'd say something much less convoluted, something like: VK6AR, 59104 from VK6AHR He

Foundations of Amateur Radio There was a time when I took my computer out into the field to do my portable logging. That's still true for contests, but when I'm hunting for an elusive DX station, I no longer take with me all the bits that are required to make that level of technology work. I've come to the realisation that less is more. Especially with portable operations in parks and on summits. This move to paper will actually simplify your life whilst you're enjoying the rare stations you can hear. So, if you're using paper logs and you are wanting to make actual contacts, how do you do this without going insane? Normally you'd find a station, log their call, put down the frequency, scratch it out when the contact failed, rinse and repeat. The end result is a page full of scratched out callsigns with no structure and little chance to accurately log these into your normal station log. The best way to overcome this is to take a leaf from N1MM, a brilliant piece of logging software that deserves a whole s

Foundations of Amateur Radio Today I'm going to talk about magic. In the past I've made mention of the magic that is Amateur Radio. There are those who think that our hobby isn't magic and that everything that we do in this field is understood and documented. I think that this is both wrong and unhelpful, since there is much to learn, much to discover and much to invent. Amateur Radio isn't dead, it's full of life, full of things that are continuing to develop, evolve and grow. Let me give you an example. In radio there is a phenomenon called the "FM Capture Effect". Explaining how you experience it is simple. If you have two FM transmitters on the same frequency, and you're using an FM receiver, one of the FM transmitters will win, that is, you'll hear one and not the other. Unlike in AM and SSB transmissions, where you hear both at the same time, the FM Capture Effect causes the receiver to pick one over the other. As an aside, it's because of this effect that aviation and HF communication mostly prefe

Foundations of Amateur Radio This technology driven community of radio enthusiasts makes me laugh on occasion. Today I had to laugh when I realised that we spend an awful lot of time talking about antennas and radios and feed lines and impedance and propagation and electronics and a whole lot of subject in-between and around that. It stuck me that one conversation that we don't have, is the one about microphones. Specifically how to actually use one. I've been around hundreds of radio amateurs, seen them speak into their microphone, witnessed them standing at a lectern presenting their latest project, observed them attempting to rally the troops during a HAMfest by yelling into a microphone and heard them on-air. I came to the realisation that despite our familiarity with the technology, by enlarge, the amateurs I observed are no better than the general public when it comes to using a microphone. Actually, I think as a community we're worse, because we won't be told how to do it. So, I'm going to tell you

Foundations of Amateur Radio There is a curious phenomenon related to how we operate that is pervasive within our community. As an inexperienced ham, I would turn on my radio and tune around and hear nothing. I'd change bands and do it again. Over time I'd work my way through the bands I'm allowed on and find no activity. On rare occasions I'd venture into the wide unknown and see what other bands were doing, ones where I wasn't allowed to transmit due to my license restrictions, and find lots of people talking to each other, making noise and having fun. More often than not, this band of feverish activity was 20m. For a long time I ascribed magical properties to this 20m band. There was always propagation, people were always there and it seemed that if you wanted to make contacts, that was the place to be. Over time I participated in contests with other amateurs, operating a club station and finding myself on 20m making contacts. I began to believe that 20m was this amazing place where stuff was always ha

Foundations of Amateur Radio The thing I like about our community is that there is always something new brewing, someone is inventing something, making something or doing something. It amazes me that the level of ingenuity is boundless. During the week someone asked the question, "What's the difference between AM and FM?" and while answering that could incorporate hand waving, arrows and drawings, I came across a much simpler explanation, which simply says it all. Credit goes to redditor EmmetOT. Imagine replacing radio with light, this isn't a stretch, since it's part of the same spectrum. Replace a radio transmitter with a light bulb. AM is using a dimmer, changing the brightness, to send information. FM is changing the colour of the light to send information. I could stop right there, but there is so much more going on in our community. If you've been out of Amateur Radio for a while, and I know, this happens to the best of us, you'll be forgiven in thinking that nothing is the same as it was, while w

Foundations of Amateur Radio When you use your trusty multi-meter to measure resistance across a 50 Ohm resistor, it shows 50 Ohm, but when you use it across a piece of 50 Ohm coax, you see either infinity, or 0. Similarly, when you measure across a folded-dipole, you see 0, not 300 Ohm. Does this mean that a 50 Ohm resistor is somehow different than a 50 Ohm piece of coax and why is the feed-point impedance of a folded dipole 300 Ohm, when your multi-meter clearly says it's 0? Does this mean that there are two types of Ohm? Today I'm going to explain why this is and what's going on. Yesterday I started reading up on the subject and every single explanation I came across went into deep ju-ju with scary maths, using complex and imaginary numbers. I did a bit of that in my dark past, but none of that is needed to understand what's happening. As you know, there is such a thing as Direct Current or DC - we use it with batteries and little power supplies, in simple circuits and all manner of day-to-day activiti

Foundations of Amateur Radio Today I'm concluding my breakdown of the contest that I participated in recently as a mobile station. I planned to make my contacts on one band and I did that. Feedback indicated that there were other contacts to be had on other bands, but switching bands is a non trivial affair with my current set-up. I planned to have a common frequency that would be a local cluster of activity, except it never happened that way because others decided to do their own thing. This meant that my antenna was tuned for the top end of the band, rather than the more typical centre of activity. I expected to work several home stations and managed to do so with two, but that was much lower than I expected and planned for, so my overall score didn't reach the planned levels, even if it was triple last year's effort. I planned to drive a circuit in about 90 minutes, instead it took about three hours. Fortunately there were lots of mobile stations about which helped me much more than expected. I keep

Foundations of Amateur Radio Today I'm going to look at the actual on-air activity of the contest. Previously I've talked about the preparation and planning, as well as the doing, in terms of mechanics, what to bring, where to put it and how to power it all. At the most basic level, a contest is a combination of two things, making and taking calls. It's an important point, so I'll say it again. A contest is two things, sitting on a frequency and call CQ and have other stations call you, and, it's also hunting up and down the dial finding other stations who are calling CQ. These two sides, being the instigator of the contact, and being the responder, are needed to make points. Even the most advanced contest station with multiple operators and transmitters will do both these things and when you're on your own you too need to do this. One reason for this is that in a contest others are doing the exact same thing. They're also swapping between both these activities to pick up extra points and multipliers. An

Foundations of Amateur Radio Today I'm going to talk about the doing of a contest. Previously I discussed the preparation and you can go back to that and have a listen online, search iTunes for my callsign, VK6FLAB. The contest I participated in was a 24 hour contest. It started at 2pm local time on a Saturday and ran the whole 24 hours. If I was sitting in a shack, I might have and in the past actually have, operated during most of that. Seeing that this time around I was planning to be mobile, I needed to get sleep in between driving from location to location. In my car I have a suction cup stuck to the front windscreen which holds the head of my radio. It's mostly within reach, but if I operate for a little while, extending my arm gets tiring, so if that's the case, I drop the steering wheel, push it forward and modify my seat position. A better solution would be to find a better location, but I've not managed that yet. I keep looking at other set-ups, but haven't found one that works for me. I'll let

Foundations of Amateur Radio Training is a word that is steeped in tradition, it conjures up images of classrooms, teachers, chewing gum stuck to the bottom of your desk and being called upon to attend the front of the class to explain something based on the misapprehension that you did your homework. Fortunately this is a hobby and training is something you can do yourself, to yourself, by yourself at your own pace. Of course, you can choose to do it with others, but it's not required as such. We talk about being prepared for doing stuff, but what do we actually do to make that happen? I've said many times that I like to do contests. In fact, I'm preparing for one right now. This particular contest awards points for making a contact and doubles the points, a so-called multiplier, every time I work a different area. So, what does my training for this look like, what preparation have I done and what am I doing right now? My first step was to read the rules, the specifics of what is proscribed, what is pe

Foundations of Amateur Radio Today I'm going to talk about getting started. In the past I've mentioned that it's a good idea to find a community, a club or a local mentor to get you going in this hobby, and that still stands. You really need to find some like-minded, available humans to share this experience with. That being said, there are some things that you can do on your lonesome. An often asked question is: "What radio should I buy?" The answer to that question can be long and involved, but it boils down to this: "What ever you can afford." That answer in and of itself isn't that helpful. Do you get a $40 cheap hand-held or a $4000 all-singing and dancing radio? My best answer to that is: "Buy your second radio first." What I mean is that if you spend your money on a $40 radio today, how long will you enjoy it and how long will it be until you spend your next bit of money and is that $40 investment a waste of money? I'm not making a value judgement here, the answer is still: "What ever you can affo

Foundations of Amateur Radio This crazy hobby keeps sending curve balls to me. You've heard me talk in the past about missed opportunities. There are times when you look back and ask yourself: "What was I thinking?" Over the past, oh boy, I just looked it up, two years, I have been struggling with an antenna system that I could use while mobile. I took delivery of 4 single band antennas, one for 80m, one for 40m, 15m and one for 10m. I also purchased a boot-lip mount and some other things like coax switches and adapters. I've been attempting to make these antennas work with very, very limited success. They work just fine, they tune up as expected, show the SWR curve that the manufacturer has helpfully printed on a little card that comes with each antenna and generally are sturdy, compact and wonderful, but only if they're installed on something other than my car. In desperation a year ago I purchased a tuner for my radio, so at least I can trick it into transmitting. I have made very few contacts, added o