Welcome to the getting started guide. The world of digital amateur radio contains a lot of content, modes, protocols, and software. It can be overwhelming. This page and the website is an attempt at tackling the massive undertaking of making a one stop shop for amateur radio digital modes.
Key Concepts
These are concepts you should get familiar with before moving forward in your journey.
Data
This description for data will be in the context of amateur radio. Data is just information. This information, when transmitted over radio can come in various speeds (baud) and bandwidth. Baud is a unit of transmission speed equal to the number of times a signal changes state per second. Bandwidth is the amount of spectrum taken up by a data transmission. If Baud is the speed of water flowing through a pipe, bandwidth is the size of the pipe in circumstance. Most of the data in amateur radio related activities is transmitted and encoded in much the same way audio is, and so often audio cables and sound cards are used as pipes and interfaces.
CAT
CAT (Computer Aided Transceiver) is an Interface. It is the interface that allows you to control settings on your radio via computer connection. Most often times, you will hear this described as “CAT Control”. This is handy because most work on digital ham radio is done via PC. With CAT, you no longer have to control the radio physically to adjust frequencies and other various settings. CAT can also be used to toggle PTT(Push to Talk), which toggles transmit on your radio. A CAT most often is a serial connection to your radio. Sometimes this interface is bundled with a Digital interface we will talk about next.
Digital Interface
A Digital interface is a term used to describe how your radio is connected to your computer. Digital interfaces can come in many shapes and sizes, and some of them are even built into radios already! The digital interfaces job is to relay data received by your radio to your computer, and to relay data generated by your computer to your radio. Often times, this interface also contains a CAT interface alongside it. These interfaces are often times very different in terms of setup and functionality, so that’s why we have the radio database to look for what works best for each. These often connect to a dedicated data jack on your radio, or sometimes use your radios hand mic port. Besides getting data in and out of your radio, a digital interface also comes with a method to toggle transmit so that it can go out on the air. Your digital interface can have either PTT (Push To Talk) or VOX (Voice Operated Exchanged).
PTT and VOX
In order to actually send data, your radio must toggle transmission as data is being fed from your computer. This comes in 2 flavors, PTT(Press to Transmit), and VOX (Voice Operated Exchanged).
PTT is a method of toggling your radio transmit programmatically. With PTT, methods employed by your CAT interface are used to turn your transmitter on and off as needed instantly as data is being sent to your radio. This can some in a variety of flavors, but most often involves sending a command over your serial port via your CAT interface.
VOX on the other hand activates your radios transmit at the presence of a signal on your data interface. This is because VOX is normally used to transmit without pressing a button when using voice communications. With Digital operation, VOX is hand, because we can activate the radios transmitter when data is fed from the computer, without the need for any other interface or connection. On the flip side, it’s not as timely or accurate. The beginning of a transmission can be clipped off if the transmitter is “slow to open” as they say. Often times, the transmitter can also stay keyed to long to compensate for the variability of present audio signal. This can cause you to lose information if another station starts transmitting before your VOX “closes”
Digital Modulation Vs Protocol Vs Mode
In the context of amateur radio, a modulation is a method used to modulate and demodulate information into data that can be transferred via radio wave. For example, 8-GFSK is a modulation that the FT8 Protocol is built on and constructed with. A Digital Protocol ( in amateur radio context) is an outline and standard for how a piece of data should be constructed and deconstructed (encoded and decoded) into a frame that can be sent over and received by a Digital Interface. If a digital protocol is the language we speak, modulation is the vocal cords that create the sound. Now a digital mode lives on top of these concepts as the “wrapper”, and gives us a “doing” verb that we use to refer to these concepts. Once we have a software that preforms the modulation, outlines the protocol, we now have a “mode” that we “do” and a protocol that we “use”