Magnavox 6TNA

Some amplifiers like the Magnavox 6TNA (trunk network amplifiers) or 6GNA (Global network amplifiers) have higher insertion losses when compared to line-extenders such as Magnavox 6LE97.

Video and data carriers suffer from the effects of cable and flat losses in a cable plant. Forward and reverse path amplification are necessary at predetermined locations, in order to compensate for these losses. The return amplifier ( 5 – 42 MHz) has typically an operational gain of approximately 18 dB. The unity gain concept is utilized in cable TV to compensate for the cable spacing and flat losses between amplifiers. This means that for a certain cable spacing (loss) at the highest frequency, when compensated by an amplifier with equal gain will produce a unity gain outcome. For example, if a length of coaxial cable at 42 MHz frequency exhibits a 6 dB loss and is in series with a flat loss from a directional coupler of 12 dB, the total losses would be 18 dB. A return amplifier with 18 dB of operational gain would be needed to compensate for these losses: -18 dB (loss) + 18 dB (gain) = 0 dB or unity gain.

June 19, 2011

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