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あらすじ・解説
Foundations of Amateur Radio Thirteen years ago I opened my mouth to express my thoughts on what to do with an amateur license after hearing an operator complain they needed more power to talk to a station across 600 kilometres, whilst I used the same 10 Watts to communicate with a station nearly 15,000 kilometres away. In all, I've shared my thoughts some 700 times, documenting my journey though this majestic hobby, describing what I've been up to, reporting my successes and failures, sharing my observations and making recommendations. I've built projects and attempted to start new processes, I've encouraged, cajoled, on occasion berated or applauded as I found it. Throughout the experience I've attempted to build this wonderful community, to inspire and to grow it. Sometimes I might even have succeeded. I could not have done this without you. So, thank you. If I haven't mentioned your name or responded to your email, it's not because I didn't see your contribution. You have delighted me and lifted me up and I thank you for sharing your thoughts. At this point you might wonder if I'm hanging up my microphone and to that I say: No, not even close. Instead I'm continuing with this experiment, rough and ready though it is. It occurs to me that over the years I've started a great many projects and documented them as they happened, either here, or on my vk6flab.com website, or on GitHub. These projects take time and effort that go beyond what you encounter here. Sometimes it's hours, sometimes it's weeks. Recently a lot of my musings have been about things I've wanted to do, rather than describing things that I've done. Mind you, not for lack of desire. I want to try something different. I'm going to, at least for the next little while, bring you along with a project as I'm building it. No doubt I'll get distracted by squirrels along the way, but I'm going to attempt to build something for us as a community, for amateur radio, because I want to actually do something, rather than talk about it and I need to manage my limited resources and this way I get to build something and you get to have me sharing my thoughts. From my perspective, win-win. So, let's dive in. Amateur radio is a hobby that takes all kinds. A lot of activity is curtailed by money, or rather, lack of money. That doesn't have to be the case and I think I can show you how. That's not to say that this is going to cost nothing, but you can likely start with what you already have and work your way up as your budget allows, rather than require a significant outlay just to get your toes wet. Over the past few weeks I've been talking about a toolkit called GNU Radio. It can be used to build systems that can process data, like say radio signals which come in all shapes and sizes. You can start by connecting an antenna to a sound card and use that as a radio tuner. You can also use a sound card as a way to listen to signals coming in via the Internet, or a radio you might already own. Sound cards exist in most computers but can be purchased for around $10. If you want to handle more data, you can spend $50 and use an RTL-SDR dongle. This incremental path continues. You can build a digital radio, or buy a learning kit, or something else, all the while still being part of the same ecosystem. I want to build a system where you can experiment with radio without needing to buy new hardware every time you want to try something new. I want it to work with a sound card as well as with the latest $7,000 radio you can get shipped to your door. I want to do this in such a way that we can start to embrace all that is possible within the realm of software. Ultimately I want to be able to use any signal source anywhere and GNU Radio seems ideally suited as the tool for the job. I envisage that we'll build a distributed system, where signal processing and the signal itself don't have to be in the same spot, which is useful for a whole host of reasons, even though it increases the level of complexity by at least an order of magnitude. This isn't going to be easy. It's not going to be working tomorrow, perhaps not even a year from now and as long as new radios are invented, it will never stop, but we'll see how it goes. For example, I spent a week attempting to install GNU Radio on my Macintosh, asked two expert groups and got nowhere. In stark contrast, I installed it on my Linux Debian workstation and the example I tried worked out of the box. In other words, plenty of obstacles to overcome. Before I go, I'll make this explicit. I want this to be open source, so anyone can play. I haven't yet decided on which specific license to use, but I'm cognisant that there are many large companies making obscene amounts of money from the volunteer efforts of the open source community and as one of the volunteers, I'd like to be able to pay for food and a roof over my head. I expect and appreciate your feedback, so don't be shy. I'm Onno VK6FLAB