Our opinion piece this month is about opportunities for experimentation in the Amateur Radio service. We think personal computers will find themselves tightly integrated into a variety of future Amateur Radio technologies. But before we start with the editorial, we have some adminstrative comments we'd like to make.
First some good news - as long time visitors to our web site know, we had to move our web site to a new server on somewhat short notice this past summer. Fortunately, thanks to Mike Cheponis, K3MC, we found a home for our web site on the business server of California Wireless, Inc, at http://www.wireless.com where we run on a Sun workstation connected to dual T-1 Internet connections. Any slowness you observe in accessing our website is due to the Internet itself bogging down and is not due to the web server.
California Wireless is not an Internet Service Provider but is a consultant in RF and Infrared technology design. Mike also hosts the Infrared Data Association (IrDA) web site at http://www.irda.org. The IrDA is an industry standards group working towards interoperable short range cordless communications using low cost infrared light.
And now for the so-so news - while surfing the web, we recently came across a commercial business amateur radio web site that has copied about half a dozen of our web pages, made some minor changes and then placed their own copyright notice on our work. We work hard to research and create our free web site - we self fund this entire operation and between the two of us, average about 20 hours of work on this web site every week. We encourage you to copy our material for non-commercial uses according to our easy reprint policy. We think we are pretty generous!
So when we found that this commercial site had stolen our web pages, we thought they were rude, inconsiderate and unethical. We are not going o mention their name and give them any free publicity but if you happen to stumble upon an Amateur Radio business web site that has pages that strongly remind you of ours, you might want to run away as fast as you can - if they choose to be rude and steal from others - are you sure you'd want to be their next victim, I mean, customer? Its almost funny that they take something and then hang it out in public for all to see!
Technological advancement has produced two trends that are important to the future of ham radio experimentation. The first of these is the conversion of all signals to digital data streams. Many everyday products have converted from analog to digital - these include digital cordless phones, digital cellular phones and digital satellite TV, and soon to come, digital audio broadcasting. The second trend is the widespread availability of high performance computing. With all signals becoming "just bits", the opportunity to massage those bits with personal computer software is the next step.
There is tremendous opportunity to begin working - at the ham radio hobbyist level - with personal computers and software applications to create new experiments in radio communications. Several decades past many towns had electronics parts stores and many of us enjoyed tinkering with electronic parts. Today, electronics parts are hard to find. But software development tools are available everywhere. Many hams have developed a fear of the Internet, claiming that it will swallow up anyone who might otherwise have been interested in radio technology. Perhaps true, but keep in mind that many of these people are fundamentally technologists at heart and are fascinated with computer software, programming and communications.. The ham radio experimenter of today and tommorrow is going to be playing with software - and a lot less hardware. Software is the future and there are many exciting possibilities for amateur radio software-based experimentation.
Software experimentation is an opportunity to attract a new breed of technologist, tinkerer and experimenter to the field of ham radio - software enthusiasts. Ham radio should not attempt to compete with the Internet nor personal computers but should strive to offer new opportunities through the synergies of new technologies. As in any technology centric field, we must be forward looking and forward thinking. Communications technology is changing at extraordinary speed now. Focus on the future, not on the past.
The following list is a compendium of possibilities for software experimentation in ham radio. This list presents examples of appropriate software experimentation.
Today there is a large amount of freeware, shareware and commercial software available to the radio amateur. This software represents traditional PC applications including contest logging tools, satellite tracking software, packet radio terminal software and BBS programs, "TCP/IP" implementations and new products such as HF band propagation prediction software. Many of these applications can and are written by hobbyists ranging from neophytes to experts. Many more applications that work with ham radio will continue to appear and evolve over time. But the more exciting opportunity, lies in the processing of signals and the manipulation of data streams being sent over radio (such as the APRS packet reporting system) to create new types of applications. We've seen already PC software that emulates the oscilliscope - and provides a lot more functionality than the scopes we played with 10 or 20 years ago. Signal processing applications have a bright future in ham radio.
We hear quite a few of ham radio operators exchanging road traffic information on local repeaters during the afternoon commute. Meanwhile, the federal government is planning to spend millions of dollars creating prototype traffic alerting systems in selected metropolitan areas to determine if such systems can be used to improve traffic flow, to help designers create better user interfaces, and to test different types of infrastructure to support such information systems. Hams practically have all the pieces to this puzzle in hand right now. Systems like APRS - the automatic position reporting system - and occassional data inputs from hams on the freeways - could build such a system today, test the concepts and advance the state of the art. There are many possibilities for creating new applications using ham radio technology and software. A decade ago a few of us toyed with the idea of building a packet radio and GPS-based aircraft collision avoidance system. We had almost all the pieces to do this back in the mid-80s. Only recently has such as system been demonstrated in actual aircraft by academic, government and commercial developers.
QST has run an article or two on the concept of software radios. Basically, you need an RF stage and an IF stage or two, and then a conversion of the analog signal to bits. Once the signal is in digital form, demodulation can be performed in software. A single radio can decode AM, FM, SSB, ACSB, RTTY, FAX, SSB - you name it - all using digital signal processing software. Lots of work can be done in this area by the ham radio hobbyist. In fact, you could invent your own modulation scheme.
Additional work can be applied to new forms of weak signal operation. Digital technology can often work at extremely low power levels for a given communications path. By manipulating the bits, in software, reliable communications can be maintained under difficult path conditions. We've seen advertisements of "DSP filters" that are implemented in software and rely upon your PC hardware to perform the analog to digital conversions. This field is ripe for experimentation.
Hams have been operating low speed packet radio networks since the early 1980s. Back then, a 1200 baud telephone modem was exciting - 1200 bps packet radio was pretty cool. But with 28,800 bps telephone modems now common place and inexpensive, that old 1200 bps packet radio looks pretty dated. This leads to two ideas:
1. Obviously, packet radio communications needs to move to 9,600 bps or faster speeds (such as the 56 kbps GRAPES modem). X.25-based networks are dead or dying in the real world and the same is true for AX.25 - its time to move onto TCP/IP-based networks that interface to the Internet. Amateur data communications that does not interface to the Internet is a thing of the past and unlikely to be a significant part of our future.
2. 1200 bps packet radio technology might better be deployed as Amateur 2-way messaging systems. The technology exists to create simple, low cost, 2-way messaging units based on AX25 for the delivery of personal, paging-like messages. Units could be built with integral 2 meter receivers or designed merely to connect to the audio output of your HT. Why not?
In a world where everything goes to bits, most radio designers are trying to achieve more bits per hertz - that is to say, to pack more data per radio channel and to build ever faster radio data links. But what if we turn the problem on its head and pose a different problem - what if the goal were to build a radio as cheaply as possible and not care about the speed? For example, we'll bet that a super slow speed radio - maybe 10 to 30 bps - could be built for dirt cheap - CW proves this! To receive a slow bit stream like this requires only that the incoming data pulses be fed to a suitable inexpensive microcontroller (or heck, your PC's audio input port) and counted by the CPU for a simple demodulation scheme. A crystal controlled super slow speed digital link (SSSDL) could be built for almost nothing - and used to deliver ham radio bulletin information, paging alerts and who knows what else?
Data transfer speed is not always important. If you look at your PC screen (or handheld computer - on store shelves now in the form of an HP200LX or Apple Newton and coming this Christmas in other forms from other manufacturrers) and a message has arrived, its not terribly important if the message took 30 seconds or 3 minutes to transmit. All you care is that the message is there now, when you look at it. Cheap, slow speed data links provide interesting possibilities for new kinds of applications. The entire area of inexpensive radio technology continues to be a fertile field for ham radio experimentation.
Linked repeater systems are common in North America. In a linked system, one VHF repeater is typically linked to another VHF repeater on a common UHF frequency. Some systems link many repeaters together full time or at the command of a control operator. Repeater links over long distance can be implemented using digital audio over the Internet. Common software is available today to implement "Internet telephony". The technology could be easily adapted to establish a link between a repeater in say, London, U.K., and San Francisco, California, USA.
Not much seems to happening in digital wireless imaging in the Amateur community. Hams have long used analog technologies like SSTV, FAX and ATV. Packet radio makes possible digital imaging, albeit very slowly at 1200 bps. With the common use of notebook computers and camcorders, you already have the ingredients for a low cost digital imaging system. A product called Snappy from Play, Inc., retails for less than U.S. $200. The Snappy plugs into a Wintel computer's parallel port and is used to grab still images from a camcorder. Many newer Macintosh computers have digital imaging built-in. So, for the cost of $200, a great many hams could be experimenting with ditigal imaging applications. You can even buy a $99 QuickCam to generate B&W digital images; a color model is also available.
The opportunity is to turn wireless imaging into a tool for public service and government directed emergency operations communications. Ericsson, the Swedish telecommunications giant has announced that they will soon be offering 64 kbps data links over the GSM-based digital cellular telephone network. On the wireless side, we can presume that this technology operates by using and combining 4 of the time slots in the GSM time division multiple access (TDMA) technology. On the landline side, the data is probably sent down conventional ISDN data connections. Based on Ericsson's advertising, we can presume that in the near future, you will be able to buy a digital still picture camera with builtin high speed GSM digital cellular technology - instantly transfer pictures to a recipient. Imagine the possibilities of this technology for public safety, traffic control, or journalism.
Using a PC on each end of the link also opens up possibilities in digital voice communications. Hams are incredibly far behind in the experimentation and deployment of digital voice technology. By comparison, Specialized Mobile Radio Service (SMRS) frequencies near 900 Mhz have converted to digital technology (see Nextel or OneComm services available throughout much of the U.S.) to provide digital phone, two-way point to point and two-way group radio functions, plus alpha paging, in a single handheld phone. At least three kinds of digital technology are being deployed in cellular telephony systems. These technologies are being deployed because digital technology enables anywhere from roughly a 2 to 10 times capacity improvement in frequency usage. That means serving 10 times more users in the same space as an existing analog system.
The FCC is pushing all radio services to develop more frequency efficient technologies. Hams are likely going to have to do the same. But so far, ham radio and digital voice technology do not appear in the same sentence.
While the world or commercial communications is jumping to digital, we wonder if there are perhaps some neat things left to do in analog communications? Analog systems are functional and low in cost. We suspect there are many interesting things yet to be done in analog communications yet commercial interests have now left analog technology to push digital technology.
And lastly, combining computers and radios makes possible the automated search for extraterrestrial radio communications signals. If you find some extraterrestrial radio signals, we are not quite sure how you will get your QSL card but we will leave that problem for someone else to solve! The idea that ham radio operators will be the first to intercept signals from extraterrestrial sources is quite reasonable - who else could have so many ears listening skyward simultaneously? Amateur astronomers have made many important discoveries and continue to make many discoveries. Amateur radio astronomy opens up still more possibilities appropriate for the technologically inclined radio amateur. And of interest, both of these areas require digital signal processing made possible with modern personal computers.
So what are you waiting for? Get out that compiler and get to
work, have fun and invent the future!
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