One question. One answer. Zero noise.
Any FCC-licensed amateur station may operate under RACES rules if it is certified by the responsible civil-defense organization for the area served.
An impedance-matching network cancels the reactive component and transforms the remaining resistance to the desired value.
Microwave systems commonly use high-gain antennas that concentrate RF energy into a narrow beam. That concentration can produce high exposure levels even when transmitter power is not unusually high.
Amateur mesh networks commonly operate on amateur frequencies that overlap spectrum used by unlicensed wireless data services.
Below 30 MHz, a spurious emission must be at least 43 dB below the mean power of the fundamental emission under the rule represented here.
Microstrip is commonly used to connect MMICs because short controlled-impedance traces can be formed directly on the circuit board.
Messages intentionally encoded to obscure their meaning cannot be transmitted over an amateur radio mesh network.
A coding rate of 3/4 means three quarters of the transmitted bits carry payload information and one quarter is forward-error-correction overhead.
A folded dipole uses a second parallel conductor connected at the ends of the half-wave element.
An isotropic radiator is a hypothetical lossless point-source reference that radiates equally in all directions.
A spectrum analyzer displays the transmitter's output as a function of frequency, making spurious signals and intermodulation products visible.
In the far field, the angular radiation pattern has stabilized and no longer changes shape as distance increases.
Amateur propagation-reporting networks commonly collect reception reports from digital modes and CW to show where signals are being heard.
Net reactance is XL - XC = 250 - 500 = -250 ohms. arctan(-250/1000) is about -14 degrees, so voltage lags current by 14 degrees.
Common-mode current can flow on a cable shield and its conductors together, causing a nominally shielded cable to radiate or receive RF.
On the channelized 60-meter band, CW must be transmitted at the center frequency of the channel.
An adaptive filter changes its response as conditions change and can reduce unwanted noise in received SSB audio.
The official E1D05 source also requires a label with the control operator's name, address, and telephone number at the station location.
Baseband is the original information-bearing frequency range before it is translated onto an RF carrier.
The official E2C10 source identifies reduced interference and improved efficiency as a reason DX stations transmit and receive on different frequencies.
A pull-up or pull-down resistor connects a signal to a supply rail so the line assumes a defined voltage when no active device is driving it.
The official E4A11 source identifies tuned-circuit resonant frequency as one quantity measurable with an antenna analyzer.
The most common optoisolator pairs an LED with a phototransistor, transferring a signal optically while maintaining electrical isolation.