So, the SSB signal is just under one-half the bandwidth of the double sideband conventional AM signal. While this redundant double band AM signal provides robust and high quality audio, it consumes a relatively wide band of spectrum.Īs the name implies, single sideband mode utilizes only one of the two AM sidebands and also omits the carrier frequency in transmission. ![]() Additionally, the AM signal includes transmission of the carrier frequency itself. The AM signal is about 6 kHz wide, and if we examine it in more detail we will find that it is actually comprised of two bands, one on each side of the carrier frequency, and they are ‘mirror imaged’ redundant bands or “sidebands.” That is, a complete voice signal is carried by each of the two sidebands comprising the AM signal. The upper sideband SSB signal is illustrated here. ![]() SSB utilizes only one of the double sidebands of AM and also omits the carrier frequency transmission. ![]() The extent of this little transmitted band of signals will vary with different types of modulation, or modes, and we refer to the extent or total range of frequencies emitted as the signal’s bandwidth, in units of hertz. So, a transmitter does not emit only that singular tuned carrier frequency, but rather it emits an entire little band of frequencies near the carrier value that is used to encode the information of all the various audio frequencies of a voice. The carrier may be thought of as a reference position for a small, contiguous band of frequencies that will all be transmitted simultaneously when the push-to-talk button is depressed and some voice audio is provided to the microphone. When an operator tunes up a specific frequency on a transceiver, that displayed frequency value is the carrier frequency. Let’s unfold that last statement for the uninitiated new hams.įirst, some bandwidth basics: A radio signal is comprised of a range of transmitted frequencies. What’s so ‘special’ about it? Besides just encoding voice information with variations in signal amplitude, or power, SSB consumes a little less than half the bandwidth of a full “double band” AM signal. What is SSB? Single sideband is a special form of amplitude modulation (AM). This video lesson will help you to visualize some of the practical considerations of SSB operations. Read on to take a closer look at the basics of SSB phone mode and to better understand its complexities and operating nuances relative to FM channelized ops. Single sideband is the predominant phone mode used for over-the-horizon skip propagation via the ionosphere. Single sideband phone may be used on the VHF and UHF bands available to the Technician Class licensee, on the 10-meter band phone segment available to Technicians (28.3 to 28.5 MHz), and on all HF phone sub-bands available to higher license classes. Generally, SSB signals tend to propagate greater distances and exhibit more graceful degradation over distance than FM signals. ![]() Single sideband phone ops offer a broader range of radio contact opportunities, including long distance and international communications. However, after mastering repeaters and gaining comfort with on-air FM phone QSOs, the next step for many hams is the more challenging domain of single sideband (SSB) phone operations. The channelized world of VHF/UHF FM offers relatively simplicity of operations and is a great way to get on the air immediately upon earning the Technician Class license. A new Technician Class operator is likely to get started in ham radio with VHF and UHF phone operations using FM simplex channels and repeaters.
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