NOTE: This subject is in the early stages of development. Expect it to change substantially and often.
DARS – Digital Amateur Radio Station – is the name I have given my effort to build an all-digital amateur radio station. The station is to be a distributed computer network, with each component (radios, mics, speakers, keys, computers, etc.) connecting through a digital interface.
Amateur Radio is going digital with software defined radios and digital communication modes. A DARS station should carry that process to its logical conclusion.
There are a number of goals that I have for this project.
Let's take a closer look at these things.
I'm relatively new to Amateur Radio, having earned my license in 2016. I like technology, and get pleasure from exploring how things work and what they can do. I want to experience as much of our hobby as possible, which means building a station that will do lots of things. And that, of course, leads to technical problems the have to be overcome.
The complexity of my station seems to increase exponentially as I pursue more bands and modes. The result is a bewildering assortment of wires and adapters, CW keys and mics and computers. Making it all work together is a significant challenge. Life would be sweeter if I could simplify the station so as to eliminate some of the problems I face.
I came to radio from the world of computers, which benefits immensely from the use of standard protocols and interfaces. I was deeply disappointed to learn that no such thing applies to Amateur Radio equipment.
Incompatible equipment interfaces abound, in no small part stemming from brand lock-in promoted by the manufacturers. Icom gear won't work with Yaesu, Yaesu won't work with Kenwood, and so on. I want to get away from this.
The challenge here is setting up a station that that:
This involves development of appropriate software and interfaces needed to make it work.
There are many possibilities for things to do here.
I get great pleasure and satisfaction from working solutions to problems such as this. That's what hobbies do for us.
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 both systems 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 are boundless. Think of some of that already are being realized:
Flex, Expert, and Elecraft provide proprietary client software, with varying support for Windows, Linux, Mac, Android, and iOS devices. All but Expert offer public APIs that can be used to develop custom third-party client software. All this contributes to the radios being part of a distributed network – though the lack of API standards substantially complicates things.
The SDR dongles and online SDR receivers also illustrate 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 external speakers 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]