T2B13 Single Sideband Above 50 MHz

T2B13 from the Technician License Course Section 4.2, Bands, Band Plans, and License Privileges:  Which of the following is true of the use of SSB phone in amateur bands above 50 MHz?

A. It is permitted only by holders of a General Class or higher license
B. It is permitted only on repeaters
C. It is permitted in at least some portion of all the amateur bands above 50 MHz
D. It is permitted only on when power is limited to no more than 100 watts

Let’s first clarify what is meant by bands that are “above 50 MHz.” This language means that the frequency of the bands is higher than 50 MHz. And remember that wavelength – the approximate value we use as handy band names – will be smaller as frequency increases.

The wavelength associated with 50 MHz is computed as:  300 ÷ 50 MHz = 6 meters. The question is referring to the bands with wavelength monikers of 6 meters and smaller. This includes the set of 6-, 2-, and 1.25-meter bands, as well as the 70-, 33-, and 23-centimeter bands. (Additional, less commonly utilized bands in the microwave range are also implied with this question.) In essence, this question is referring to the amateur bands in the VHF, UHF, and higher ranges.

ARRL Band Plan Chart:  Additional detailed band plans are published at the ARRL web site.

ARRL Band Plan Chart: Additional detailed band plans are published at the ARRL web site.

By far, the most common phone mode used on the VHF and UHF frequencies is FM. Frequency modulation is used with voice repeaters in the VHF and UHF ranges. However, single sideband is also used on these bands by many amateur operators. The recommended band plans from the ARRL, and most local region band plans, identify specific portions of VHF and UHF bands for single sideband operations.

For example, on the 6-meter band SSB operations are recommended from 50.1 MHz to 50.3 MHz, with 50.125 MHz being the designated SSB calling frequency. On the 2-meter band the frequency range from 144.100 MHz to 144.275 MHz is designated for single sideband mode. The 222.1 MHz to 222.25 segment of the 1.25-meter band is for SSB, and 70-centimeter band is designated for SSB from 432.1 MHz to 432.3 MHz. In each case the upper sideband (USB) convention is used. Higher frequency bands have similar SSB recommended sub-bands in the ARRL band plans.

Single sideband operations on VHF and UHF bands provides extended communications range.

Single sideband operations on VHF and UHF bands provides extended communications range.

Learn more about single sideband operations on the 2-meter band in this Shack Talk article by Bob KØNR.

Learn more about the difference in operations with SSB in this Ham Radio 101 article, with accompanying video.

Why use SSB on the VHF and UHF bands? Several good reasons exist! First, SSB is a much more power efficient phone mode than is FM. The bandwidth of the SSB signal in about 3 kHz, where the FM bandwidth will range between 5 – 15 kHz or greater. For equivalent power of transmission, the SSB signal will have a greater average power across the transmit band and promote better propagation.

Single sideband is a special form of AM, and it is more power efficient than FM phone.

Single sideband is a special form of AM, and it is more power efficient than FM phone.

Combined with the horizontal polarization standard with SSB operations on VHF and UHF bands, the effective range of communication will usually be significantly greater than with typical FM phone operations. For these reasons, SSB is the primary phone mode used by VHF+ contesters.

VHF+ contesters use SSB as a primary phone mode.

VHF+ contesters use SSB as a primary phone mode.

Learn more about VHF+ contesting in this previous Feature article, with accompanying video.

The answer to Technician Class question T2B13, Which of the following is true of the use of SSB phone in amateur bands above 50 MHz?” is “C. It is permitted in at least some portion of all the amateur bands above 50 MHz.

 Related Questions:  T2A10, T1B10, T1B11, T1B13