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AUDITING - relating to cable television, it refers to physically checking to see where all the connections are, the quality of the system, etc. Systems can recover big money by catching thieves and preventing construction violations.  Top

CHANNEL BANKS - generally for T1s or E1s. Usually a simple combining/multiplexing system for the DSO (64Kb/s) lines. Generally a set and forget box. If it has the ability to change based on customer usage or other dynamic features, it is called a multiplexer.  Top

CHURN - the turnover rate of customers, particularly cable television system customers where for a variety of reasons (theft, poor service, transient client base, etc.) the same addresses are regularly dropping and adding service.  Top

COAX - a round cable with a single wire in the middle, surrounded by a plastic or plastic and air dielectric which is surrounded by either a solid metal or braided metal grounded shield.  Top

Db - a logarithmic relationship of power. Refers to radio and light sources, etc.  Top

DIELECTRIC - a non-conductive material used to separate conductive wires. Typically used to describe the material used to fill the space between the center conductor and the shield on coaxial wire.  Top

DID - Direct Inward Dialing - phone lines in a building that only ring into the building as opposed to POTS.  Top

DOD - Direct Outward Dialing - can only be used to call out and not receive calls.  Top

DSS - Digital Satellite System.  Top

DUPLEX - refers to two-way communications. Full duplex is similar to your phone in that both directions of communication occur at the same time. Half duplex is like a walkie-talkie, two-way communication is possible, however only one party may transmit at a time. Spread spectrum generallyis half duplex, however buffers make it appear as if it is full duplex.  Top

E1 - a transmission method defined at 2.048Mhz, although it can be used in its entirety for video and Ethernet, etc. It is typically subdivided into 32 channels of 64Khz each (typically only 30 channels are available for use). These are the standard requirements of most voice, fax and modem lines. The 32 channels are then multiplied together to for a single E1 and demultiplexed to the other end.  Top

ETHERNET - a data communications standard in either thick-net, thin-net, 10BaseT and now 100Mb/s standard from 2 to 100Mb/s. Note: Be wary of microwave vendors, particularly spread spectrum, that promise 10Mb/s connectivity but only can deliver 2Mb/s continuous throughout (or less).  Top

FAA - Federal Aviation Administration - involved in a discussion of communications as they can control the height and lighting of communication towers.  Top

FADE MARGIN - the difference between the receive signal level on a good day and what the radio will fail at. Must be large enough to overcome losses induced by rain and other natural occurrences. Is expressed in Db.  Top

FREQUENCY SEARCH - checking your intended frequency against the F.C.C. database to insure that your new system will not interfere with other systems.  Top

FREZNEL ZONE (sometimes freznel) - an area around the path that should be kept clear of all reflective surfaces so that out of phase/delayed phase signals are not received that have been reflected off of such surfaces. Caution must be used in determining such surfaces. Water is obvious, however tree growth or even a low lying inversion layer over farmland can cause problems if it enters the freznel zone.  Top

FULL DUPLEX - see duplex.  Top

GAIN - the effective amplification caused by an active amplifier, or by a passive antenna effecting the concentration of signal in a specific direction.  Top

GO 95 - rules pertaining to the construction of aerial communication systems such as telephone & cable television.  Top

GO 128 - rules pertaining to the construction of underground communication systems.  Top

GHZ - gigahertz - one billion complete variations in amplitude per second.  Top

HALF DUPLEX - see duplex.  Top

HELIAX - a form of coax that is corrugated on the outside. This helps with the flexibility of the cable. (Some believe it helps with low loss as well).  Top

ISDN - Integrated Services Digital Network - a way to have true 64or 128Kb/s connectivity. Also can be used for cheap, full time access - ask us.  Top

LAST MILE - an expression used for the cabling or other communication medium from the closest fiber optic point or other type of high speed/large through-put service point to the end user’s equipment. This may be actually 100 feet to the street or telephone pole, or may be a new line back to the local telephone central office (C.O.), etc.  Top

LICENSING - a process of securing you own license with the F.C.C. (Federal Communications Commission), which should (and generally does) insure that no one else will interfere with your licensed signals. (There can have serious penalties for interfering with a F.C.C. licensed system).  Top

Mb/s - Megabits/second - one million bits of information per second.  Top

MHZ - megahertz - one million complete variations in amplitude per second.  Top

MODULATION - a pulsing of a signal changing the tone, frequency, phase, amplitude or any other feature of a system to convey a message. This is where the "mod" in modem comes from (the "dem" stands for demodulate, the reverse that happens at the far end to put the desired signal back in its original format).  Top

MOUNT - a structure, usually 3-4’ in height that attaches to a building roof, parapet or tower and has the proper size pipe or hardware to secure a microwave or satellite dish or any other antenna not suitable for direct attachment.  Top

MULTIPLEXER - used for combining (and separating) T1s/DS1s into DS3s, or DSOs into DS1/T1. Either a high capacity unit or a smart unit (as compared to a channel bank) that can dynamically change as user demand warrants.  Top

OMNI DIRECTIONAL - refers to an antenna similar to most radio antennas on cars. A vertical rod, sometimes with a few wires ticking out horizontally at the base to act as a ground plane. Omni directional antennas typically transmit and receive equally in all directions and have low gain.  Top

OPTICAL SYSTEM - any system that uses modulated light as a transmission medium. Can be transmitted over fiber optics or, as referenced here, can use a high power beam in open space up to 1,000 feet. Fog and rain are limiting factors, as a systems can work much further on clear days.  Top

PATH ANALYSIS - this is often a computer generated (although it can be done by hand) profile taking all the information gathered in the site survey and combining it with the specifications of the radio that is expected to be used. It takes into account the basic line of sight, curvature of the earth (this starts to be important in approximately 6 miles), the frequency and the freznel zone required for the radio, as well as rain fade for the area being considered.  Top

POTS - Plain Old Telephone System - describes the old standard phone wire and connection as opposed to DID, DOD, ISDN, T1, etc.   Top

PRIOR NOTIFICATION - notices sent to all persons occupying the same frequency band within 2-300 miles (depending on your output power, frequency, etc). This gives other license holders the right to petition against your receiving a license to operate and notifies them of who may be causing any problems in the future. (I personally have never seen a petition filed for a new microwave system that has had a proper frequency search completed).  Top

SIMPLEX - one-way transmission; television and commercial radio, etc. See duplex.  Top

SITE SURVEY - looks at the proposed mounting structures (buildings, towers, etc.) and determines their suitability for the antennas being proposed and considers the prospect of getting the cables/power from the antenna to the indoor equipment as well as the mounting of the indoor equipment. It also encompasses looking at the entire path both physically for trees, buildings, water towers, mountains, etc., and on a topographicmap (either paper or electronic) and looking for obvious obstructions and anything that might be in the path or in the nearby path that will affect the beam.  Top

SPREAD SPECTRUM - a type of high bandwidth, low power transmission system originally developed by the U.S. government that cannot be easily detected or intercepted. Current versions also use dynamic frequency hopping to change frequency if anything jams the signal. F.C.C. regulations do not require these radios to be licensed. Available commercially in 900Mhz, 2.4Ghz or 5.8Ghz versions. Top

T1 - a transmission method defined at 1.544Mhz. Although it can be used in its entirety for video and Ethernet, etc., it is typically subdivided into 24 channels of 64Khz each. These are the standard requirements of most voice, fax and modem lines. The 24 channels are then multiplexed together to for a single T1 and demultiplexed to the other end.  Top

TOWER - any structure designed to support communications equipment. It can be a tall building or wooden pole but is primarily used to describe a 3 or 4 legged steel structure built expressly for the purpose. Note that towers are generally designed and built to support the original dishes/antennas only and should be checked by a qualified structural or civil engineer before adding additional equipment.  Top

VOICE MAIL - a way of directing and recording messages on a phone system.  Top

VSAT - Very Small Aperture Terminal used to describe duplex, fixed satellite stations typically 18" to 8’ in diameter.  Top