Ultra-high frequency (UHF) designates the ITU radio frequency range of electromagnetic waves between 300 MHz and 3 GHz (3,000 MHz), also known as the decimetre band or decimetre wave as the wavelengths range from one to ten decimetres (10 cm to 1 metre). Radio waves with frequencies above the UHF band fall into the SHF (super-high frequency) and EHF (extremely high frequency) bands, all of which fall into the microwave frequency range. Lower frequency signals fall into the VHF (very high frequency) or lower bands. See Electromagnetic spectrum and Radio spectrum for a full listing of frequency bands.

High frequency (HF) radio frequencies are between 3 and 30 MHz. Also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters (ten to one hundred metres). Frequencies immediately below HF are denoted Medium-frequency (MF), and the next higher frequencies are known as Very high frequency (VHF). The Shortwave range (2.310 - 25.820 MHz) used by international broadcasters is part of the HF frequency spectrum. In aviation virtually the entire spectrum (2 - 29.999 MHz) is used for HF communications.

The ionosphere often refracts HF radio waves quite well. This phenomenon is known as skywave propagation. Because of these characteristics this range is extensively used for medium and long range radio communication. However, suitability of this portion of the spectrum for such communication varies greatly with a complex combination of factors:

These and other factors contribute, at each point in time for a given communication path, to a

The maximum usable frequency regularly drops below 10 MHz in darkness during the winter months, while in summer during daylight it can easily surpass 30 MHz. It depends on the angle of incidence of the waves; it is lowest when the waves are directed straight upwards, and is higher with less acute angles. This means that at longer distances, where the waves graze the ionosphere at a very blunt angle, the MUF may be much higher. The lowest usable frequency depends on the absorption in the lower layer of the ionosphere (the D-layer). This absorption is stronger at low frequencies and is also stronger with increased solar activity (for example in daylight); total absorption often occurs at frequencies below 5 MHz during daytime. The result of these two factors is that the usable spectrum shifts towards the lower frequencies and into the Medium Frequency (MF) range during winter nights, while on a day in full summer the higher frequencies tend to be more usable, often into the lower VHF range.^{[citation needed]}

Tom Moulton (born November 29, 1940) is an American record producer, and originator of the remix, the breakdown section, and the 12-inch single vinyl format.

Thomas Jerome Moulton was born in Schenectady, New York, United States.

Moulton worked as a model at the Bookings and Ford agencies, before beginning his production career. Before that, he had worked in the music industry, holding a sales and promotion job at King Records (from 1959 to 1961), and similar positions at RCA and United Artists. He eventually left due to his disgust at the industry's dishonesty. His music career re-started in the late 1960s, with a self-made tape of overlapping songs created for the Fire Island bar and restaurant, The Sandpiper.

He was responsible for the first continuous-mix album side, on Gloria Gaynor's disco album, Never Can Say Goodbye, earning him the title the "father of the disco mix". Among some of his other success in mixing songs are The Three Degrees' "Dirty Ol' Man", MFSB featuring The Three Degrees "Love Is The Message", B.T. Express' "Do It ('Til You're Satisfied)", The Trammps' "Disco Inferno", The People's Choice's "Do It Any Way You Wanna", Andrea True's "More, More, More", plus First Choice's "Doctor Love" and Claudja Barry's album, The Girl Most Likely.