Ads
related to: hjs hf df 1000 watt meter power analyzer parts
Search results
Results From The WOW.Com Content Network
An antenna analyzer measuring SWR and complex impedance of a dummy load. MFJ-269, MFJ Enterprises Inc. An antenna analyzer or in British aerial analyser (also known as a noise bridge, RX bridge, SWR analyzer, or RF analyzer) is a device used for measuring the input impedance of antenna systems in radio electronics applications.
High-frequency direction finding, usually known by its abbreviation HF/DF or nickname huff-duff, is a type of radio direction finder (RDF) introduced in World War II. High frequency (HF) refers to a radio band that can effectively communicate over long distances; for example, between U-boats and their land-based headquarters.
Two-channel DF, using two adjacent antennas of a circular array, is achieved by comparing the signal power of the largest signal with that of the second largest signal. The direction of an incoming signal, within the arc described by two antennas with a squint angle of Φ, may be obtained by comparing the relative powers of the signals received.
For this reason, Doppler DF systems normally mount their antennas on a small disk that is spun at a high speed using an electric motor. Performing the same calculation using an antenna mounted to a disk with a diameter of 50 centimetres (20 in) diameter spinning at 1000 Hz results in: S = .25 × 1000 × 101.8 / 48 = 530 Hz
The array consisted of a ring of 120 vertical monopoles covering 2–20 MHz. Tall wood poles supported a 1,000-foot diameter (300 m) circular screen of vertical wires located within the ring of monopoles. His research is still used today to guide the design and site selection of HF/DF arrays. Records of his research are available in the ...
A signal analyzer is an instrument that measures the magnitude and phase of the input signal at a single frequency within the IF bandwidth of the instrument. It employs digital techniques to extract useful information that is carried by an electrical signal. [1] In common usage the term is related to both spectrum analyzers and vector signal ...
An SWR meter does not measure the actual impedance of a load (the resistance and reactance), but only the mismatch ratio. To measure the actual impedance requires an antenna analyzer or other similar RF measuring device. For accurate readings, the SWR meter itself must also match the line's impedance (typically 50 or 75 Ohms).
An optical power meter (OPM) is a device used to measure the power in an optical signal. The term usually refers to a device for testing average power in fiber optic systems. Other general purpose light power measuring devices are usually called radiometers , photometers , laser power meters (can be photodiode sensors or thermopile laser ...