NOTE: This subject is in the early stages of development. Expect it to change substantially and often.
DARS is my effort to build an all-digital amateur radio station. The station is to have a computer network as its core, and all components of the station (radios, mics, speakers, keys, computers, etc.) will have a network interface with which to connect to it. Amateur Radio is going digital with Software Defined Radio and digital communication modes. A DARS station will carry that process to its logical conclusion.
There are several reasons one might have for taking on a project such as this:
Let's take a closer look at how these apply to what I'm doing.
Problems I want to overcome:
Things that are new to me, but I haven't implemented.
There are many possibilities for things to do here.
I get great pleasure and satisfaction from working on things such as this. That's what hobbies do.
The object here is to build a Distributed Amateur Radio Station (DARS). In a conventional analog station, the components that make up the station are connected together by electricity flowing through physical conductors. In a distributed station, the components are connected together by data sent over a computer network. A telegraph key, for example, would have a network interface in place of wires that plug into a rig. So would a microphone, a headset, a computer – and a radio.
DARS is an extrapolation of Software Defined Radio (SDR) to produce a software defined station. Until recently, computers have effectively been peripherals of the radio, processing signals for digital modes and rig control, which are fed to the rig. With SDR, that relationship is reversed: the computer performs all the radio signal-processing functions, while the rig is effectively a transducer that sends and receives RF radiation on one side and digital data on the other. In short, the computer becomes the radio, with the rig as one of its peripheral devices.
The reasoning behind DARS is:
One way to think about this is that it is the architecture of a distributed computing system applied to an Amateur radio station. The system could be fully self-contained, open to the Internet, or some combination of the two.
Of course, a distributed station still must have hardware: RF components (transmitters, receivers, antennas), and user interfaces (keys, mics, computers, speakers). But its heart is composed of software running on computers.
The big idea here is that the pieces of a distributed station are connected together not by electrical voltages, but rather by digital data. The essential requirement of systems connected by digital data is that they both understand the form and format of the data being conveyed between them. That means some form of data standards that both systems can apply independently in order to communicate.
Think of cell phones. They are, at base, radio transceivers that convey digital data. The cellular network works because phones and towers are programmed to use standard protocols. That lets you buy a new phone and immediately start using the network. The Internet works the same way, with an unlimited number of unique systems bound together by standard protocols.
No such standards exist for Amateur Radio equipment – as anyone who has tried to connect a rig to a computer can testify. That means a system of standards would have to be developed. The object would be to enable station components to communicate with each other regardless of make and model.
To my mind, the possibilities of such a system seem boundless. Think of some of that already are being realized:
The first two, although partially distributed, suffer from being closed systems, using proprietary hardware and software.
The SDR dongles and online SDR receivers better inllustrate the potential of a distributed station, in that they can be combined with any external system that can handle the data they produce (a computer, in this case).
The loudspeakers with DSP are somewhat less clear-cut. Viewing the DSP section as three blocks – analog-to digital coverter, digital processor, digital-to-analog converter – reveals its distributed nature. Those blocks could be implemented independently and be physically separated, connected via data transfer over a network. Here is an example.
The essential aspect of DARS is that it separates station operator functions from the hardware that makes up a station. That is, station hardware is controlled not by manipulating direct physical controls (knobs, buttons) that are part of the electrical circuit, but indirectly, through computer software. A second aspect is that some of the analog hardware functions can be performed by software instead – not just its controls.
The station operator has these primary functions:
[NOTE: Partial entry; still under development]