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Homebrew is an amateur radio slang term for home-built, noncommercial radio equipment. [1] Design and construction of equipment from first principles is valued by amateur radio hobbyists, known as "hams", for educational value, and to allow experimentation and development of techniques or levels of performance not readily available as commercial products.
Amateur television (ATV) repeaters are used by amateur radio operators to transmit full motion video. The bands used by ATV repeaters vary by country, but in the US a typical configuration is as a cross-band system with an input on the 33 or 23 cm band and output on 421.25 MHz or, sometimes, 426.25 MHz (within the 70 cm band ).
A diplexer allows two different devices to share a common communications channel. Typically, the channel is a long coaxial cable, and a diplexer is often used at both ends of the coaxial cable. The plan is feasible if the two devices operate on different frequencies. The plan is economical if the diplexers cost less than running a second cable.
These are effectively a higher-performance version of a diplexer, typically with a narrow split between the two frequencies in question (typically around 2%-5% for a commercial two-way radio system). With a duplexer the high- and low-frequency signals are traveling in opposite directions at the shared port of the duplexer.
The name magic tee is derived from the way in which power is divided among the various ports. A signal injected into the H-plane port will be divided equally between ports 1 and 2, and will be in phase. A signal injected into the E-plane port will also be divided equally between ports 1 and 2, but will be 180 degrees out of phase.
A duplexer is to provide duplex (two way) communication over a single path. A diplexer is to allow two signals to be carried over a single path - i.e. to provide two-channel multiplexing . Generally a diplexer consists of a pair of filters with non-overlapping pass-bands, so it implements frequency-division multiplexing .
This method is called symmetrical double-sided two-way ranging because: It is symmetrical in that the measurements from station A to station B are a mirror-image of the measurements from station B to station A (ABA to BAB). It is double-sided in that only two stations are used for ranging measurement – station A and station B.
The cavity was a high-Q round silver-plated copper "can", with the internal diameter of 31 ⁄ 40 in (19.7 mm) and about 11 ⁄ 16 in (17.5 mm) long, with inductance of about 10 nanohenries. [5] Its front side was closed with a very thin (3 thou , or 75 micrometers) and fragile conductive membrane.