I was happy today doing some Amateur Radio Operating. I have a computer in my home office that in this case is also my “radio shack”. No, not the electronic stores. The name comes from the ham and ship radio equipment location and operating positions. At one time because of the whine of M/G (motor generator or dynamotor) sets and loud snaps of electrical arcs jumping gaps (rotary and other) radio operators were usually segregated to operate from their own “shacks” out under their antenna arrays.
The term “shack” has just stuck as the name for any non broadcast radio station transmitter/operator location. Commercial broadcast radio has a “studio” where the content is created and the transmitting location is usually elsewhere.
Today I have my “rig” (transceiver radio) hooked up to my Linux computer. Any computer will do but Linux has a long history with the spirit of radio experimentation and getting the job done with lowest cost possible. I can’t beat the price of “free” for the operating system and the software.
The mode I was using is called BPSK31. It is a Phase Shift Keying of a signal with a baud rate of only 31.25. The B stands for Binary, a non error correcting version. There is also QPSK31 with (Q meaning quadrature) error correction but that mode is not heavily used. Most systems can easily switch between the two. More specific details are also found from the ARRL (American Radio Relay league) website.
There can be up to twenty keyboard conversations going on in the width of a single sideband voice audio signal. That was the case about noon today but as you see here after 11 PM it is pretty quite with only a few weak signals that look like railroad tracks. The random characters on the screen are just decoded noise. That’s how it goes. Once locked onto one of the (selectable) vertical “tracks” visible on the lower blue “waterfall” screen (a simple mouse click), clean text will be decoded.
It is seldom necessary to use more than 15 to 30 watts of power for world wide communication when the signals are there.
Seen in the picture are several conversations (by keyboard typing) going on in 3KHz of bandwidth.