- Date: Tuesday, November 3, 2015, 7:30 PM
- Location: Danbury Hospital Creasy Auditorium
- Presenter: Michael Walters
by Andy Woodruff
Spend an evening learning how computers are used in amateur radio! Mike Walters will tell us about amateur radio, how radio operators use computers, and how he provides emergency services based on computers and radios.
Mike is a licensed amateur radio operator and the District Emergency Coordinator for the regional Amateur Radio Emergency Service (ARES) that serves our part of Connecticut. He coordinates with the Federal Emergency Management Agency (FEMA) to provide emergency communications services for agencies such as the American Red Cross. Mike will explain the various terms and nomenclature used in this field, and no background in radio will be needed to understand his presentation.
Amateur radio, colloquially-known as ham radio, has changed dramatically as computers have become available. A few decades ago, ham operators used Morse code and sent postcards to confirm overseas contacts. They can still use telegraph keys with Morse code, but now they are more often using advanced radios that may be digital, computer-controlled, or even “software-defined” as explained below. The “radios” here are “transceivers” that both transmit and receive.
Amateur radio operators must still pass technical tests to obtain Federal Communications Commission (FCC) licenses. The general public is allowed to use radio receivers to listen on public radio channels, but only licensed amateurs are allowed to broadcast in two-way communication.
Mike plans to explain several ways in which computers are used in amateur radio. First, you will not be surprised to learn that computers are used for storing information that was once handled by hand-written records. Specifically, radio operators have long kept records about each completed radio contact and even sent postcards to the street address of that contact. Now this confirmation is handled via an international database; each operator inputs the details about a particular completed radio contact, and the database matches the inputs from the two operators to confirm the contact.
Second, Mike will explain how computers can be used to control radios. For background, radios from two decades ago often had small displays and many buttons. In order to control a particular function, it was typically necessary to tap a button several times to scroll through menu options … while also squinting to see a small display. This is now easier with computer-controlled radios, because those detailed functions have been moved out of the radio and onto a computer, where it is easier to navigate with a mouse and a large screen.
Third, he will explain computer-assisted communications, in which he sends data from one computer to another, via amateur radio transceivers. Specifically, he connects a computer’s serial output port to the input of a radio transmitter … and broadcasts packets of information to a distant radio receiver … at the distant end, this receiver provides these data packets to a computer to complete the data transfer. In the past, radio amateurs used the old radio teletype (RTTY) to send data; now they can do computer-to-computer data transfers.
Fourth, Mike will explain software-defined radios. In this structure, much of the complicated signal handling and signal processing is moved from the radio hardware to computer software. This greatly simplifies the hardware, makes software upgrades possible, and enables much more complicated digital algorithms.
Fifth, Mike will explain how radio amateurs use computers to model the operation of devices, such as the radiation patterns of new antennae.
Based on the technical background described above, Mike will explain the role of computers in emergency communications. He is personally very involved in this field, and he coordinates a group of volunteers. Mike will explain how he and his colleagues send emails without use of the internet; how they use “repeater stations” on low earth orbit satellites; and how they use “gateway stations” to connect radios to the internet.
Mike will bring equipment to show. When you arrive at the auditorium, walk to the front to see equipment on the stage.