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techniques can result in greater versatility and smaller size compared to the equivalent analog circuitry. The KX2
uses a very advanced, power-efficient DSP.
ESD (electrostatic discharge): An event during which high voltages or currents appear within a radio or other
electronic device, potentially causing damage. Antennas, control cables, or the operator’s body are all potential
ESD sources. Damage can be avoided through proper handling and grounding techniques.
HF (high-frequency): Signals in the range of 3 to 30 MHz. In amateur radio, HF is usually shorthand for 160-10
meters (1.8 to 29.7 MHz), or the “HF bands.” 160 meters actually falls in the MF range (0.3 to 3 MHz).
IMD (intermodulation distortion): Unwanted signal products that are created in the various stages of a receiver or
transmitter. If all stages were entirely “clean,” there would be no IMD. In reality, every stage contributes some
distortion, with the amount of distortion being proportional to signal level. Radio designers go to great lengths to
minimize distortion, trading off circuit cost and complexity against the benefit of reduced interference.
Keyer: A device that partially automates the sending of Morse code, allowing for faster code speeds. The KX2 has
a built-in keyer function, as well as an optional attached keyer paddle (KXPD2 or KXPD3, pg. 33).
MCU (microcontroller unit): A computer or controller usually integrated onto a single integrated circuit. A
modern amateur transceiver usually has one main MCU that controls most radio functions. It may have other
smaller MCUs or co-processors that perform specific functions. The DSP in the KX2 is a specialized co-processor
(see DSP, above).
MDS (minimum discernable signal): A measure of a radio’s sensitivity, expressed in dB (decibels) relative to 1
milliwatt (0 dBm). For example, the user of a KX2 with the 20 dB preamp turned on, can typically copy a CW
signal at about -137 dBm, or 137 dB below 1 milliwatt. MDS is dependent on the receiver bandwidth, with 500 Hz
normally used for standardized measurements.
Preamp: A pre-amplifier that increases RF signals to a higher level for use by subsequent stages in a receiver. A
preamp is generally designed to contribute little noise of its own, so that it improves the noise figure of the radio
(also see MDS).
SDR (software-defined radio): A radio that performs signal modulation, demodulation, filtering, and other
functions in software. Such software can execute internally (in a dedicated DSP IC, as in the Elecraft K3S, KX3, or
KX2) or externally (in a general-purpose computer, as required with “black box” SDRs).
VFO (variable frequency oscillator): A signal source used to select a radio’s operating frequency. The KX2’s
large knob controls VFO A, while a smaller knob controls VFO B (see Using VFOs A and B, pg. 16).
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