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Bronze Member Username: HeavybHopkins, Sc Usa Post Number: 14 Registered: Jul-04 | ive been reading around and cant seem to find the much of the info i need . would someone explain gains and how to adjust them i plan on doing my own instal. someone please explain it to me |
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misterHT Unregistered guest | Gain is defined as the compressing of the vertical component of the antenna pattern, in effect causing the radiation pattern of the antenna to reach out further toward a base station or cell site. Gain is an important measure because certain gain figures are better suited to particular usage environments. For strictly urban use, a unity gain antenna is ideal. Because a unity gain antenna send the maximum signal above the horizon at a high angle, it is excellent for areas where there are tall buildings and for mountains as well. For people who live in suburban or rural areas, 3 dBd gain is recommended. The 3dBd gain antenna concentrates the maximum amount of signal at the horizon while maintaining a good high-angle signal. If you are a cellular user, there is not need to buy an antenna stronger than 3 dBd gain as the USA cellular infrastructure is designed for optimum performance using 3 dBd gain antennas. If you are using a Land Mobile Radio (LMR) system and are in a rural area, a 5dBd gain antenna is suggested as this will help to provide the maximum amount of signal at the horizon with very little high-angle signal. Gain can be expressed in many different ways. The two most common are dBd and dBi. Gain expressed as dBd is a measure referenced to a halfwave dipole. The dBi measure is referenced to a theoretical, dimensionless point source with a completely spherical radiation pattern. Since it has no directivity, any real antenna without excessive loss will provide some amount of gain when compared to the isotropic. Antenna Specialists is now providing its gain measures in both dBd and dBi so buyers can have an even basis of comparison. Cellular and PCS phones operate on radio frequency (RF) technology much the same as a car radio. The body of the car acts to block the RF signal. Just as a good car radio still needs an external antenna or the radio signal will be noisy cracked and broken, a cellular or PCS phone needs an external antenna to provide better call quality. There is no "best" mount. It all depends on your use. The important thing is to ensure the whip extends above the roof line of the vehicle. This will prevent the car from blocking, distorting or shading the signal pattern of the antenna. Either a window clip or magnet mount antenna will meet your needs. Both are portable and may be moved from vehicle to vehicle. Remember, though, a magnet mount antenna will adhere only to an iron/steel (OK through paint) surface. "On-Glass" antennas are easy to install and do not diminish a vehicle's value by drilling a hole. Care must be taken during installation to ensure that the antenna is mounted high up on the glass and not over defogger wires or on reflective window tint and this could impede performance. You can have an elevated-feed trunk-lip mount antenna installed. These antennas are designed to "elevate" the whip electrically so that it is above the car roof. Elevated-feed antennas require no ground plane so they may be used with fiber glass or plastic vehicles. The "best" choice for optimum performance considerations is a roof mount antenna. At this height the antenna is free from any vehicular obstruction. The roof also acts as a ground plane for the antenna and actually becomes part of the antenna's electrical system. Just remember, this antenna type does require drilling a hole in the vehicle. |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 4397 Registered: Dec-03 | nice, but completely out of context and in this instance of no use. gains are actually properly referred to as input sensitivity. they are a means of matching the line drive voltage from the head unit to the input stage of the amplifier(s.) more info on them and how to set them here: http://p079.ezboard.com/fcaraudiotalkfrm27.showMessage?topicID=34.topic |
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Silver Member Username: Jonathan_fGA USA Post Number: 927 Registered: May-04 | That was humorous, and very informative lol. Completely off topic, though. |