| Amateur radio is a series of narrow regulatory carve-outs of the radio spectrum for the public good, somewhat like a national park. It has existed since the discovery of radio itself. RF is now a mature formal engineering discipline, but the underlying knowledge and practice has also been passed down through amateur channels for generations in an almost guild-like fashion. It is now one of the very few sanctioned ways in which a person interested in radio may put their own electrical components together and see how it works on a workbench. In the US there are two major distinctions between licenses. The basic Technician class license mainly lets you access VHF and up - these radio waves propagate based on line of sight. The general focus in this area of the spectrum comes from the sheer utility of radio. Then, the General and Extra class licenses let you operate more fully on shortwave. These are lower frequencies that interact with the ionosphere, giving them the curious property of reaching around the planet. (Extra opens up a little more spectrum, and is recognized by some international treaties allowing you to operate while abroad). The basic starter equipment for a technician is a handheld or mobile radio. The line-of-sight limitation on VHF is overcome by the use of repeaters. A no-stakes way to sample the activity in your vicinity is to get an RTL-SDR dongle and tune in to the 2 meter and 70 cm amateur bands. The classic starter kit for a general is an HF radio and homemade dipole. The radio will realistically cost a couple hundred dollars, but the antenna can be just scrap wire and modest coax cable. The size of the antenna is determined by the wavelength at which it operates. The two most common beginner bands are 20M and 40M. A dipole for those wavelengths is about 33' and 66' of wire respectively, but the wire does not have to run in a straight line. You can use a WebSDR to peek in on the activity for free. My personal interest in all of this is SOTA -- Summits On The Air. It is a radio sport that involves taking portable shortwave transmitters up to mountain peaks. It is equal parts exploration, since many of the peaks in my region lack even trail access; and invention, as the physical realities of mountain climbing necessitate radios and antennas made for the purpose. The actual radio exchange from the peak is simple - who is calling, how well they can hear you, and where they are located, and maybe a pleasantry or two. There is a great deal of camaraderie from the other operators, and you never know whether your next contact will come from San Francisco or coastal France. |