From Amateur-radio-wiki
Jump to: navigation, search
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0 - 9


NB: Narrow band. Also noise blanker.

NBFM : Narrow band FM

Negative : no, incorrect

Negative copy : unsuccessful transmission

Negative Feedback A process in which a portion of the amplifier output is returned to the input, 180 degrees out of phase with the input signal.

Negative Offset : Used in repeater systems where the repeater input frequency is lower than the output frequency.

Net : a scheduled and structured on-air meeting of amateurs - often run and controlled by clubs. A directed net designates one station to act as net controller; that station is responsible for inviting other stations to check in (by sending their call signs) and then sequentially assigns each station a window of time in which to send traffic to other stations on the net. Intent is to avoid message collisions which otherwise may be caused by multiple stations attempting to send simultaneously.

NiCad : Nickel Cadmium, generally refers to a type of rechargeable battery with 1.2 volts per cell.

NiMH : Nickel Metal Hydride, generally refers to a newer type of rechargeable battery with the same voltage as NiCad cells but increased capacity. NiMH cells do not exhibit the memory effects associated with partial discharge of NiCads, but do still need to be recharged before use if they have been stored for a month or more.

Noise : Unwanted elecromagnetic energy that can interfere with signal transmission or reception.

NPN : A type of bipolar transistor that has a layer of P-type semiconductor material sandwiched between layers of N-type semiconductor material.

Null : A position in the radiation pattern of an Antenna where the radiation is zero or approaches zero

NVIS : near-vertical-incidence-skywave, a propagation mode where signals are reflected back down from directly overhead. Useful for relatively short-distances, overcoming the limitations of the usual "skip-zone" distance"